Publications

Review papers

Benjamin S. Williams, “Terahertz quantum cascade lasers.” Nature Photonics, vol. 1, September 2007, pp. 517-525. http://dx.doi.org/10.1038/nphoton.2007.166

Miriam S. Vitiello, Giacomo Scalari, Benjamin S. Williams, and Paolo DeNatale, “Quantum cascade lasers: 20 years of challenges,” Optics Express, vol. 23, 5167-5182 (2015) http://dx.doi.org/10.1364/OE.23.005167

Book Chapters

Benjamin S. Williams and Christopher A. Curwen, “Metasurface-based THz Quantum Cascade Lasers,” In Mid-Infrared and Terahertz Quantum Cascade Lasers, Cambridge University Press ISBN: 9781108552066 (June 2023).

Benjamin S. Williams and Luyao Xu, “Terahertz metasurface quantum-cascade VECSELs,” In Vertical External Cavity Surface Emitting Laser. VECSEL Technology and Applications, Wiley-VCH (September 2021) ISBN: 978-3-527-80797-0. https://doi.org/10.1002/9783527807956.ch5

Benjamin S. Williams and Qing Hu, “Terahertz Lasers,” In Encyclopedia of Modern Optics (2nd Edition), Elsevier, vol. 1, pp. 379-386, 2018.         https://doi.org/10.1016/B978-0-12-803581-8.09639-9

Q. Hu, B. S. Williams, S. Kumar, A. W. M. Lee, Q. Qin, J. L. Reno, H. C. Liu, and Z. R. Wasilewski, “Terahertz Quantum Cascade Lasers and Real-Time T-Ray Imaging,” In Future Trends in Microelectronics: Up the Nano Creek, Wiley-Interscience, pp. 347-358, 2007.

Q. Hu, B. S. Williams, M. R. Melloch, and J. L. Reno, “Terahertz emitters based on intersubband transitions.” In Future Trends in Microelectronics: The Nano Millenium, Wiley, New York, pp. 242-52, 2002.

Preprints

Journal Publications

*Undergraduate Author

  1. Anthony D. Kim, Daniel McGovern*, and Benjamin S. Williams, “Multi-bounce self-mixing in terahertz metasurface external-cavity lasers,” Optics Express, vol. 32, 18880-18895 (2024). https://doi.org/10.1364/OE.523012
  2. Mohammad Shahili, Sadhvikas J. Addamane, Anthony D. Kim, Christopher A. Curwen, Jonathan H. Kawamura, and Benjamin S. Williams, “Continuous-wave GaAs/AlGaAs quantum cascade laser at 5.7 THz,” Nanophotonics, January 16, 2024. https://doi.org/10.1515/nanoph-2023-0726
  3. Sidharth Thomas, Sam Razavian, Wei Sun, Benyamin Fallahi Motlagh, Anthony D. Kim, Yu Wu, Benjamin S. Williams, Aydin Babakhani, “A 0.4-4 THz PIN Diode Frequency Multiplier in 90nm SiGe BiCMOS,” IEEE J. Solid. State Circuits, vol. 58, pp 2407-2420,  July 4, 2023. https://doi.org/10.1109/JSSC.2023.3289129 
  4. Christopher A. Curwen, Jonathan H. Kawamura, Darren J. Hayton, Sadhvikas J. Addamane, John L. Reno, Benjamin S. Williams, and Boris S. Karasik, “Optical injection locking of a THz quantum-cascade VECSEL with an electronic source,” Optics Letters, vol. 48, pp. 3809-3812, June 12, 2023. https://doi.org/10.1364/OL.492182
  5. Christopher A. Curwen, Jonathan H. Kawamura, Darren J. Hayton, Sadhvikas J. Addamane, John L. Reno, Benjamin S. Williams, and Boris S. Karasik, “Phase locking of THz QC-VECSELs to a microwave reference,” IEEE Transactions of Terahertz Science and Technology, vol. 13, pp. 448-453, May 29, 2023. https://doi.org/10.1109/TTHZ.2023.3280451
  6. Yu Wu, Christopher A. Curwen, John L. Reno, Benjamin S. Williams, “RF injection locking of THz metasurface quantum-cascade VECSEL,” Laser and Photonics Reviews, vol 2023, 230007, March 25, 2023. https://doi.org/10.1002/lpor.202300007 
  7. Anthony D. Kim, Christopher A. Curwen, Yu Wu, John L. Reno, Sadhvikas J. Addamane, and Benjamin S. Williams, “Wavelength scaling of widely-tunable terahertz quantum-cascade metasurface lasers,” IEEE Journal of Microwaves, vol. 3, pp 305-318, January 2023. https://doi.org/10.1109/jmw.2022.3224640
  8. Christopher A. Curwen, Sadhvikas J. Addamane, John L. Reno, Mohammad Shahili, Boris S. Karasik, Benjamin S. Williams, and Jonathan H. Kawamura, “Measurement of gain and absorption of a THz quantum-cascade metasurface free-space amplifier,” AIP Advances, vol. 12, 115205 Nov 2, 2022. https://doi.org/10.1063/5.0122154
  9. Yu Wu, Christopher A. Curwen, Darren J. Hayton, John L. Reno, Benjamin S. Williams, “Continuous wave operation of terahertz metasurface quantum-cascade VECSEL with a long intra-cryostat cavity,” Applied Physics Letters, vol. 121, 191106, Nov 11, 2022. https://doi.org/10.1063/5.0107667
  10. Christopher A. Curwen, Sadhvikas J. Addamane, John L. Reno, Mohammad Shahili, Jonathan H. Kawamura, Ryan M. Briggs, Boris S. Karasik, and Benjamin S. Williams, “Thin THz QCL active regions for improved continuous-wave operating temperature,” AIP Advances, 11, 125018, 2021. (Editor’s pick) https://doi.org/10.1063/5.0071953
  11. Yue Shen, A. D. Kim, M. Shahili, C. A. Curwen, S. Addamane, J. L. Reno, and B. S. Williams, “THz time-domain characterization of amplifying quantum-cascade metasurface,” Applied Physics Letters, vol. 119, 181108 2021. https://doi.org/10.1063/5.0067690
  12. Y. Wu, Y. Shen, S. Addamane, J. L. Reno, and B. S. Williams, “Tunable quantum-cascade VECSEL operating at 1.9 THz,” Optics Express, 29, 34695-34706 2021. https://doi.org/10.1364/OE.438636
  13. Y. Wu, S. Addamane, J. L. Reno, and B. S. Williams, “Multi-mode lasing in terahertz metasurface quantum-cascade VECSELs,” Applied Physics Letters, 119, 111103, 2021. https://doi.org/10.1063/5.0061391
  14. C. A. Curwen, J. L. Reno, and B. S. Williams, “Broadband metasurface design for terahertz quantum-cascade –VECSEL,” Electronics Letters, vol. 56, 1264-1267, 2020. https://doi.org/10.1049/el.2020.1963
  15. C. A. Curwen, J. L. Reno, and B. S. Williams, “Terahertz quantum-cascade patch-antenna VECSEL with low power dissipation,” Applied Physics Letters, vol. 116, 241103, June 16, 2020. https://doi.org/10.1063/5.0008867
  16. C. A. Curwen, J. L. Reno, and B. S. Williams, “Broadband continuous single-mode tuning of a short-cavity quantum-cascade VECSEL,” Nature Photonics, vol. 13, 855–859, September 23, 2019. https://doi.org/10.1038/s41566-019-0518-z
  17. D. Ren, K. M. Azizur-Rahman, Z. Rong, B.-C. Juang, S. Somasundaram, M. Shahili*, A. C. Farrell, B. S. Williams, and D. L. Huffaker, “Room-Temperature Midwavelength Infrared InAsSb Nanowire Photodetector Arrays with Al2O3 Passivation,” Nano Letters, vol. 19, 2793-2802, January 24, 2019. http://dx.doi.org/10.1021/acs.nanolett.8b04420
  18. D. Ren, X. Meng, Z. Rong, M. Cao, A. C. Farrell, S. Somasundaram, K. M. Azizur-Rahman, B. S. Williams, and D. L. Huffaker, “Uncooled Photodetector at Short-Wavelength Infrared Using InAs Nanowire Photoabsorbers on InP with p-n Heterojunctions,” Nano Letters, vol. 18, 7901-7908, November 16 2018. http://dx.doi.org/10.1021/acs.nanolett.8b04420
  19. B. A. Burnett, A. Pan, C.-O. Chui, B. S. Williams, “Robust Simulation of Terahertz Quantum Cascade Laser Active Regions,” IEEE Trans. Terahertz Science and Technology, vol. 8, 492-501, September 2018. http://dx.doi.org/10.1109/TTHZ.2018.2851396
  20. C. A. Curwen, J. L. Reno, and B. S. Williams, “Terahertz Quantum Cascade VECSEL with Watt-Level Output Power,” Applied Physics Letters, vol. 113, 011104, July 2 2018. https://doi.org/10.1063/1.5033910
  21. L. Xu, C. A. Curwen, J. L. Reno, and B. S. Williams, “High performance terahertz metasurface quantum-cascade VECSEL with an intra-cryostat cavity,” Applied Physics Letters, vol. 111, 101101, Sept. 5 2017. http://dx.doi.org/10.1063/1.4993600 (APL Editor’s Pick)
  22. A. Pan, B. A. Burnett, C.-O. Chui, and B. S. Williams, “Density Matrix Modeling of Quantum Cascade Lasers without an Artificially Localized Basis: A Generalized Scattering Approach,” Physical Review B, vol. 96, 085308, August 15, 2017. https://doi.org/10.1103/PhysRevB.96.085308
  23. D. Ren, A. Farrell, B. S. Williams, D. Huffaker, “Seeding Layer Assisted Selective-area Growth of As-rich InAsP Nanowires on InP Substrates,” Nanoscale, vol. 9, 8220-8228, June 28, 2017. https://dx.doi.org/10.1039/C7NR00948H
  24. L. Xu, C. A. Curwen, D. Chen, J. L. Reno, T. Itoh, and B. S. Williams, “Terahertz metasurface quantum-cascade VECSELs: theory and performance,” IEEE Journal of Selected Topics in Quantum Electronics, (Invited paper) vol. 23, 1200512, Nov.-Dec. 2017. https://doi.org/10.1109/JSTQE.2017.2693024 (featured on cover)
  25. L. Xu, D. Chen*, C. A. Curwen, M. Memarian, J. L. Reno, T. Itoh, and B. S. Williams, “Metasurface quantum-cascade laser with electrically switchable polarization,” Optica, vol. 4, 468-475 (2017). https://doi.org/10.1364/OPTICA.4.000468
  26. B. A. Burnett and B. S. Williams, “Design strategy for terahertz quantum dot cascade lasers,” Optics Express vol. 24, 25471-25481, October 31 2016   https://doi.org/10.1364/OE.24.025471
  27. L. Xu, D. Chen*, T. Itoh, J. L. Reno, and B. S. Williams, “Focusing metasurface quantum-cascade laser with a near diffraction-limited beam,” Optics Express, vol. 24, 24117-24128 October 17 2016. https://doi.org/10.1364/OE.24.024117
  28. D. A. Chu*, P. W. C. Hon, T. Itoh, and B. S. Williams, “Feasibility of graphene CRLH metamaterial waveguides and leaky wave antennas,” Journal of Applied Physics, vol. 120, 013103, July 2016. http://dx.doi.org/10.1063/1.4955138
  29. B. A. Burnett and B. S. Williams, “Origins of terahertz difference frequency susceptibility in mid-infrared quantum cascade lasers,” Physical Review Applied, vol. 5, 034013, March 2016. http://dx.doi.org/10.1103/PhysRevApplied.5.034013
  30. L. Xu, P. W. C. Hon, C. Curwen, Q.-S. Chen, T. Itoh, and B. S. Williams, “Metasurface external cavity laser,” Applied Physics Letters, vol. 107, 221105 (2015) http://dx.doi.org/10.1063/1.4936887 .
  31. M. S. Vitiello, G. Scalari, B. S. Williams, and P. DeNatale, “Quantum cascade lasers: 20 years of challenges,” Optics Express, vol. 23, 5167-5182 (2015) http://dx.doi.org/10.1364/OE.23.005167 .
  32. B. A. Burnett and B. S. Williams, “Density matrix model for polarons in a terahertz quantum dot cascade laser,” Physical Review B, vol. 90, 155309, 2014. http://dx.doi.org/10.1103/PhysRevB.90.155309
  33. P. W. C. Hon, Z. Liu, T. Itoh, and B. S. Williams, “Leaky and bound modes in terahertz metasurfaces made of transmission-line metamaterials,” Journal of Applied Physics vol. 113, 033105, January 18 2013. http://dx.doi.org/10.1063/1.4776761
  34. A. A. Tavallaee, P. W. C. Hon, Q.-S. Chen, T. Itoh, and B. S. Williams, “Active terahertz quantum-cascade composite right/left-handed metamaterial,” Applied Physics Letters vol. 102, 021103, January 14 2013. http://dx.doi.org/10.1063/1.4775666
  35. P. Senanayake, C.-H. Hung, J. Shapiro, A. Scofield, A. Lin, B. S. Williams, D. L. Huffaker, “3D Nanopillar optical antenna photodetectors,” Optics Express vol. 20, pp. 25489-25496, November 5 2012. http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-23-25489
  36. P. W. C. Hon, A. A. Tavallaee, Q.-S. Chen, B. S. Williams, and T. Itoh, “Radiation Model for Terahertz Transmission-Line Metamaterial Quantum-Cascade Lasers,” IEEE Trans. Terahertz Science and Technology vol. 2, no 3, pp. 323-332, May 2012. http://dx.doi.org/10.1109/TTHZ.2012.2191023 Winner of 2012 IEEE Transactions on THz Science and Technology Best Paper Award.
  37. Z. Liu, P. W. C. Hon, A. A. Tavallaee, T. Itoh, and B. S. Williams, “Terahertz composite right/left handed transmission line metamaterial waveguides,” Applied Physics Letters vol. 100, 071101 Feb 13, 2012. http://dx.doi.org/10.1063/1.3684250
  38. P. Senanayake, C.-H. Hung, J. Shapiro, A. Lin, B. Liang, B. S. Williams, D. Huffaker, “Surface plasmon enhanced nanopillar photodetectors,” Nano Letters vol 11, pp. 5279-5283, 2011. http://dx.doi.org/10.1021/nl202732r
  39. A. A. Tavallaee, B. S. Williams, P. W. C. Hon, T. Itoh, and Qi-Sheng Chen, “Terahertz quantum-cascade laser with active leaky-wave antenna,” Applied Physics Letters vol. 99, 141115 October 7, 2011.
    http://link.aip.org/link/doi/10.1063/1.3648104
  40. D. Ren, J. N. Hovenier, R. Higgins, J. R. Gao, T. M. Klapwijk, S. C. Shi, A. Bell, B. Klein, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Terahertz heterodyne spectrometer using a quantum cascade laser,” Applied Physics Letters, vol. 97, 161105 October 18, 2010.
    http://link.aip.org/link/APPLAB/v97/i16/p161105/s1
  41. J. Gambari, A. I. Fernandez-Dominguez, S. A. Maier, B. S. Williams, S. Kumar, J. L. Reno, Q. Hu, and C. C. Phillips, “Thresholdless coherent light scattering from subband polaritons in a strongly coupled microcavity,” Physical Review B, vol 82, 121303(R) 2010.
    http://link.aps.org/doi/10.1103/PhysRevB.82.121303
  42. A. A. Tavallaee, P. W. C. Hon, K. Mehta, T. Itoh, and B. S. Williams, “Zero-Index Terahertz Quantum-Cascade Metamaterial Lasers,” IEEE J. Quantum Electronics, vol. 46, no 7, July 2010, pp 1091-1098.
    http://dx.doi.org/10.1109/JQE.2010.2043642. (covered in Nature Photonics, Research Highlights, July 2010 vol 4, pp. 408-409).
  43. A. W. M. Lee, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Tunable Terahertz Quantum Cascade Lasers with External Gratings,” Optics Letters, vol 35, April 1 2010, pp. 910-912.
    http://dx.doi.org/10.1364/OL.35.000910
  44. C. A. Wang, A. Goyal, R. Huang, J. Donnelly, D. Calawa, G. Turner, A. Sanchez-Rubio, A. Hsu, Q. Hu, B. Williams, “Strain-compensated GaInAs/AlInAs/InP quantum cascade laser materials,”, J. Crystal Growth, vol. 312, pp.1157-1164 (2009). http://dx.doi.org/10.1016/j.jcrysgro.2009.11.005
  45. Q. Qin, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Tuning a terahertz wire laser,” Nature Photonics, vol 3, pp. 732-737 (2009). http://dx.doi.org/10.1038/nphoton.2009.218
  46. Khosropanah, A. Baryshev, W. Zhang, W. Jellem, J.N. Hovenier, J.R. Gao, T.M. Klapwijk, D.G. Paveliev, B. S. Williams, S.Kumar, Q. Hu , J. L. Reno, B. Klein, J.L. Hesler , “Phase-locking of a 2.7-THz quantum cascade laser to a microwave reference,” Optics Letters, vol 34, no 19, Oct 1 2009, pp. 2958-2960.
    http://www.opticsinfobase.org/ol/abstract.cfm?URI=ol-34-19-2958
  47. A. Wade, G. Fedorov, D. Smirnov, S. Kumar, B. S. Williams, Q. Hu & J. L. Reno, “Magnetic-field-assisted terahertz quantum cascade laser operating up to 225 K.” Nature Photonics, vol 3, Jan 2009, pp. 41-45.
  48. G. Scamarcio, M. S. Vitiello, V. Spagnolo, S. Kumar, B. Williams, Q. Hu, “Nanoscale heat transfer in quantum cascade lasers.” Physica E, vol. 40, April 2008, pp. 1780-1784.
    http://dx.doi.org/10.1016/j.physe.2007.09.168
  49. A. W. M. Lee, Qi Qin, S. Kumar, B. S. Williams, Q. Hu, and J. L. Reno, “High-power and high-temperature THz quantum-cascade lasers based on lens-coupled metal-metal waveguides.” Optics Letters, vol. 32, 1 October 2007, pp. 2840-2842. http://dx.doi.org/10.1364/OL.32.002840
  50. Benjamin S. Williams, “Terahertz quantum cascade lasers.” Nature Photonics, vol. 1, September 2007, pp. 517-525. (review article, > 800 citations) http://dx.doi.org/10.1038/nphoton.2007.166
  51. S. Kumar, B. S. Williams, Qi Qin, A. W. M. Lee, Q. Hu and J. L. Reno, “Surface-emitting distributed feedback terahertz quantum-cascade lasers in metal-metal waveguides.” Optics Express, vol. 15, 8 January 2007, pp. 113. http://www.opticsinfobase.org/abstract.cfm?URI=oe-15-1-113
  52. A. W. M. Lee, Qi Qin, S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “Real-time terahertz imaging over a standoff distance (>25 meters).” Applied Physics Letters, vol. 89, 2 October 2006, pp. 141125.
    http://link.aip.org/link/?APPLAB/89/141125/1
  53. A. Baryshev, J. N. Hovenier, A. J. L. Adam, I. Kašalynas, J. R. Gao, T. O. Klaassen, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Phase-locking and spectral linewidth of a two-mode terahertz quantum cascade laser.” Applied Physics Letters, vol. 89, 17 July 2006, pp. 031115.
    http://link.aip.org/link/?APPLAB/89/031115/1 (Reprinted in Virtual Journal of Nanoscale Science and Technology)
  54. B. S. Williams, S. Kumar, Q. Qin, Q. Hu and J. L. Reno, “Terahertz quantum-cascade lasers with double resonant-phonon depopulation.” Applied Physics Letters, vol. 88, 26 June 2006, pp. 261101.
    http://link.aip.org/link/?APPLAB/88/261101/1
  55. A. W. M. Lee, B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Real-time imaging using a 4.3-THz quantum cascade laser and a 320×240 microbolometer focal-plane array.” Photonics Technology Letters, vol. 18, no. 13, 1 July 2006, pp. 1415-1417. http://dx.doi.org/10.1109/LPT.2006.877220 (featured on cover)
  56. E. E. Orlova, J. N. Hovenier, T. O. Klaassen, I. Kasalynas, A. J. L. Adam, J. R. Gao, T. M. Klapwijk, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Antenna model for wire lasers.” Physical Review Letters, vol. 96, 5 May 2006, pp. 173904. http://link.aps.org/doi/10.1103/PhysRevLett.96.173904 (Reprinted in Virtual Journal of Nanoscale Science and Technology)
  57. J. L. Adam, I. Kašalynas, J. N. Hovenier, T. O. Klaassen, J. R. Gao, E. E. Orlova, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Beam pattern of terahertz quantum cascade lasers with subwavelength cavity dimensions.” Applied Physics Letters. 88, no. 15, 10 April 2006, pp. 151105.
    http://link.aip.org/link/?APPLAB/88/151105/1
  58. S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “1.9-THz quantum-cascade lasers with one-well injector.” Applied Physics Letters, vol. 88, no. 12, 20 March 2006, pp. 121123. http://link.aip.org/link/?APPLAB/88/121123/1
  59. B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “High-power terahertz quantum-cascade lasers.” Electronics Letters, vol. 42, no. 2, 19 January 2006, pp. 89-90. http://dx.doi.og/10.1049/el:20063921
  60. B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Distributed-feedback terahertz quantum-cascade lasers with laterally corrugated metal waveguides.” Optics Letters, vol. 30, no. 21, November 2005, pp. 2909. http://dx.doi.org/10.1364/OL.30.002909
  61. H. C. Liu, M. Wächter, D. Ban, Z. R. Wasilewski, M. Buchanan, G. C. Aers, J. C. Cao, S. L. Feng, B. S. Williams, and Q. Hu, “Effect of doping concentration on the performance of terahertz quantum-cascade lasers.” Applied Physics Letters, vol. 87, 3 October 2005, pp. 141102.
    http://link.aip.org/link/?APPLAB/87/141102/1
  62. Q. Hu, B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, and J. L. Reno, “Resonant-phonon-assisted THz quantum-cascade lasers with metal-metal waveguides.” Semiconductor Science and Technology, vol. 20, no. 7, July 2005, pp. S228-36. http://dx.doi.org/10.1088/0268-1242/20/7/013
  63. A. L. Betz, R. T. Boreiko, B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Frequency and phase-lock control of a 3 THz quantum cascade laser.” Optics Letters, vol. 30, no. 14, July 2005, pp. 1837-9. http://www.opticsinfobase.org/abstract.cfm?URI=ol-30-14-1837
  64. J. R. Gao, J. N. Hovenier, Z. Q. Yang, and J. J. A. Baselmans, A. Baryshev, M. Hajenius, T. M. Klapwijk, A. J. L. Adam, T. O. Klaassen, B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Terahertz heterodyne receiver based on a quantum cascade laser and a superconducting bolometer.” Applied Physics Letters, vol. 86, 13 June 2005, pp. 244104.        http://link.aip.org/link/?APPLAB/86/244104/1
  65. B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Operation of terahertz quantum-cascade lasers at 164 K in pulsed mode and 117 K in continuous-wave mode.” Optics Express, vol. 13, no. 9, 3 May 2005, pp. 3331.       
    http://dx.doi.org/10.1364/OPEX.13.003331
  66. M. S. Vitiello, G. Scamarcio, V. Spagnolo, and B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Measurement of subband electronic temperatures and population inversion in THz quantum-cascade lasers.” Applied Physics Letters, vol. 86, no. 11, 14 Mar. 2005, pp. 111115.
    http://dx.doi.org/10.1063/1.1886266
  67. S. Kohen, B. S. Williams, and Q. Hu, “Electromagnetic modeling of terahertz quantum cascade laser waveguides and resonators.” Journal of Applied Physics, vol. 97, no. 5, 1 Mar. 2005, pp. 053106.
    http://dx.doi.org/10.1063/1.1855394
  68. B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Resonant-phonon terahertz quantum-cascade laser operating at 2.1 THz (l » 141 mm).” Electronics Letters, vol. 40, no. 7, 1 Apr. 2004, pp. 431-2.
    http://dx.doi.org/10.1049/el:20040300
  69. S. Kumar, B. S. Williams, S. Kohen, Q. Hu, and J. L. Reno, “Continuous-wave operation of terahertz quantum-cascade lasers above liquid-nitrogen temperature.” Applied Physics Letters, vol. 84, no. 14, 5 Apr. 2004, pp. 2494-6. http://dx.doi.org/10.1063/1.1695099
  70. Q. Hu, B. S. Williams, S. Kumar, H. Callebaut, and J. L. Reno, “Terahertz quantum-cascade lasers based on resonant phonon scattering for depopulation.” Philosophical Transactions of the Royal Society of London A, vol. 362, 2004, pp. 233-49. http://www.jstor.org/stable/4142447
  71. H. Callebaut, S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “Importance of electron-impurity scattering for electron transport in terahertz quantum cascade lasers.” Applied Physics Letters, vol. 84, no. 5, 2 Feb. 2004, pp. 645-7. http://dx.doi.org/10.1063/1.1644337
  72. B. S. Williams, S. Kumar, H. Callebaut, Q. Hu and J. L. Reno, “Terahertz quantum-cascade laser operating up to 137 K.” Applied Physics Letters, vol. 83, no. 25, 22 Dec. 2003, pp. 5142-4.
    http://dx.doi.org/10.1063/1.1635657
  73. B. S. Williams, S. Kumar, H. Callebaut, Q. Hu and J. L. Reno, “Terahertz quantum-cascade laser at l ~ 100 mm using metal waveguide for mode confinement.” Applied Physics Letters, vol. 83, no. 11, 15 Sept. 2003, pp. 2124-6. http://dx.doi.org/10.1063/1.1611642
  74. H. Callebaut, S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “Analysis of transport properties of terahertz quantum cascade lasers.” Applied Physics Letters, vol. 83, no. 2, 14 Jul. 2003, pp. 207-9.
    http://dx.doi.org/10.1063/1.1590749
  75. B. S. Williams, S. Kumar, H. Callebaut, Q. Hu and J. L. Reno, “3.4 THz quantum cascade laser operating above liquid nitrogen temperature.” Electronics Letters, vol. 39, no. 12, 12 Jun. 2003, pp. 915-6.
    http://dx.doi.org/10.1049/el:20030587
  76. B. S. Williams, H. Callebaut, S. Kumar, Q. Hu and J. L. Reno, “3.4-THz quantum cascade laser based on longitudinal-optical-phonon scattering for depopulation.” Applied Physics Letters, vol. 82, no. 7, 17 Feb. 2003, pp. 1015-7. http://dx.doi.org/10.1063/1.1554479
  77. B. S. Williams, H. Callebaut, Q. Hu, and J. L. Reno, “Magnetotunneling spectroscopy of resonant anticrossing in terahertz intersubband emitters.” Applied Physics Letters, vol.79, no.26, 24 Dec. 2001, pp. 4444-6.
    http://dx.doi.org/10.1063/1.1426694
  78. B. S. Williams, Q. Hu, “Optimized energy separation for phonon scattering in three-level terahertz intersubband lasers.” Journal of Applied Physics, vol.90, no.11, 1 Dec. 2001, pp.5504-11.
    http://dx.doi.org/10.1063/1.1413951
  79. B. S. Williams, B. Xu, Q. Hu, M. R. Melloch, “Narrow linewidth terahertz intersubband emission from three-level systems.” Applied Physics Letters, vol. 75, no 19, 8 Nov. 1999, pp. 2927-9.
    http://dx.doi.org/10.1063/1.125192
  80. B. S. Williams, D. Marteau, J. P. Gollub, “Mixing of a passive scalar in magnetically forced two-dimensional turbulence.” Physics of Fluids, vol.9, no.7, July 1997, pp.2061-80.
    http://dx.doi.org/10.1063/1.869326

Invited Talks at Conferences and Workshops

  1. Yu Wu, Anthony D. Kim, John L. Reno, Sadhvikas J. Addamane, Benjamin Williams, “Harmonic and sub-harmonic RF injection locking of multimode THz quantum-cascade VECSEL,” Optical Terahertz Science and Technology (OTST), April 8-12 2024, Marburg, Germany.
  2. Yu Wu, Christopher Curwen, John L. Reno, and Benjamin S. Williams, “Multi-mode lasing in metasurface QC-VECSELs under RF current modulation ,” (Invited Speaker), SPIE Photonics West 2024, February 1 2024, San Francisco, CA.
  3. Benjamin S. Williams, “Towards active mode locking in terahertz metasurface quantum-cascade lasers,” (Invited Speaker), SPIE Photonics West 2023, San Francisco, CA.
  4. Benjamin S. Williams, “Broadband terahertz metasurface quantum-cascade lasers for heterodyne and mode-locking applications,” Jet Propulsion Laboratory, Office of the Chief Scientist and Chief Technologist seminar series, October 27, 2022.
  5. Yu Wu, Christopher Curwen, John L. Reno, Sadhvikas Addamane, Benjamin S. Williams, “RF-injection induced multimoding in THz QC-VECSELs,” International Quantum Cascade Laser School and Workshop (Invited Speaker), International Quantum Cascade Laser School and Workshop (IQCLSW 2022), Monte Verita, Switzerland.
  6. Christopher Curwen, Anthony D. Kim, Yu Wu, Yue Shen, Darren J. Hayton, Jonathan H. Kawamura, Boris S. Karasik, S. Addamane, John L. Reno, Benjamin S. Williams, “Towards quantum-cascade VECSELs for terahertz heterodyne local oscillators,” (Invited Speaker), SPIE Photonics West 2022, San Francisco, CA.
  7. Benjamin S. Williams, “Metasurface external cavity THz QCLs – a flexible platform for tunable and broadband lasers,” (Invited Tutorial Speaker), International Quantum Cascade Laser School and Workshop (IQCLSW 2020), September 7-10 2020, Monte Verita, Switzerland.
  8. Christopher A. Curwen, John L. Reno, and Benjamin S. Williams, “Frequency-agile metasurface quantum-cascade VECSELs,” SPIE Photonics West 2020, February 1-7 2020, San Francisco, CA.
  9. Benjamin S. Williams, “Widely tunable terahertz metasurface quantum-cascade lasers” IEEE Photonics Conference (2019), September 29-October 3 2019, San Antonio, CA.
  10. Christopher A. Curwen, John L. Reno, and Benjamin S. Williams, “High-power terahertz metasurface external cavity quantum-cascade lasers,” IEEE Research and Applications of Photonics in Defense (RAPID 2019), May 19-21 2019, Miramar Beach, FL.
  11. Benjamin S. Williams, “Terahertz metasurface quantum-cascade lasers: broadband and high-power operation,” Conference on Lasers and Electro-Optics (CLEO 2019), May 5-10 2019, San Jose, CA.
  12. Benjamin S Williams, Christopher A. Curwen, John L. Reno, “High-power terahertz metasurface quantum-cascade VECSELs,” SPIE Photonics West 2019, February 2-7 2019, San Francisco, CA.
  13. Benjamin S. Williams, “High-power and tunable terahertz quantum-cascade VECSELs”, Mid-IR Optoelectronics: Materials and Devices (MIOMD 2018), Oct 7-10 2018, Flagstaff, AZ.
  14. Olivier Spitz, Jiagui Wu, Sudeep Khanal, Mathieu Carras, Chee Wei Wong, Benjamin S. Williams, Frederic Grillot, “Temperature dependence of a mid-infrared quantum cascade laser with external optical feedback,” SPIE Photonics West 2018, January 27-February 1 2018, San Francisco, CA.
  15. Benjamin S Williams, Luyao Xu, Christopher A. Curwen, Daguan Chen, John L. Reno, Tatsuo Itoh, “Quantum-cascade lasers based upon metasurfaces,” SPIE Photonics West 2018, January 27-February 1 2018, San Francisco, CA.
  16. Benjamin S. Williams, “Terahertz metasurface QC-lasers,” Intersubband Transitions in Quantum Wells (ITQW 2017), September 2017, Singapore.
  17. Luyao Xu, Christopher A. Curwen, John L. Reno, and Tatsuo Itoh, Benjamin S. Williams , “Terahertz lasers based upon amplifying reflectarray antennas,” URSI GASS 2017, August 2017, Montreal, CA.
  18. Luyao Xu, C. A. Curwen, D. Chen, J. L. Reno, T. Itoh, and B. S. Williams, “Terahertz Metasurface Quantum-Cascade VECSEL,” SPIE Optics + Photonics, August 6-10 2017, San Diego, CA.
  19. Benjamin S. Williams, “Beam engineering in terahertz quantum cascade lasers,” (Invited Tutorial Lecture), Optical Terahertz Science and Technology (OTST 2017), April 2-6 2017, London, UK.
  20. Benjamin S. Williams, Luyao Xu, Christopher A. Curwen, John L. Reno, Tatsuo Itoh “Terahertz quantum-cascade metasurface VECSELs,” SPIE Photonics West 2017, San Francisco, Feb 1, 2017. Video here: http://dx.doi.org/10.1117/12.2251447
  21. Benjamin S. Williams, “Terahertz Lasers Based Upon Metamaterial Concepts,” CLASTECH Symposium and Exhibition, Los Angeles, CA, Oct 28, 2016.
  22. Luyao Xu, Christopher Curwen, John Reno, Tatsuo Itoh, and Benjamin S. Williams, “Terahertz metasurface quantum cascade lasers,” 2016 International Conference on Optical MEMS and Nanophotonics (OMN), Singapore, June 30-Aug 4 2016.
  23. Luyao Xu, Philip Hon,  Tatsuo Itoh, and Benjamin S. Williams, “Terahertz quantum cascade metasurface external cavity laser” Intersubband Transitions in Quantum Wells (ITQW) 2015, Vienna Austria, September  6-11
  24. B. S. Williams, A. A. Tavallaee, P. W. C. Hon, T. Itoh, Qisheng Chen, “Terahertz quantum-cascade lasers with composite right/left handed metamaterial waveguides and antennas,” SPIE Optics+Photonics 2013, August 25-29 2013, San Diego, CA.
  25. B. S. Williams, “Terahertz composite right/left handed metamaterial waveguides,” (Invited Tutorial Lecture), School of Photonics 2013: Where photonics meets electronics, Cortona, Italy, May 20-23 2013.
  26. B. S. Williams, A. A. Tavallaee, P. W. C. Hon, Z. Liu, T. Itoh, “Terahertz quantum-cascade lasers based on transmission-line metamaterial waveguides,” WOCSEMMAD 2013 (Workshop on Compound Semiconductor Materials and Devices), February 18-20, New Orleans 2013.
  27. B. S. Williams, A. A. Tavallaee, P. W. C. Hon, Z. Liu, T. Itoh, Q. Chen, “Terahertz quantum-cascade lasers based on transmission-line metamaterial waveguides,” MIOMD-XI (Mid-Infrared Optoelectronics: Materials and Devices), Sept 4-8 2012, Chicago, IL.
  28. B. S. Williams, A. A. Tavallaee, P. W. C. Hon, Z. Liu, Q. Chen, T. Itoh, “Transmission-line metamaterial antennas for THz quantum-cascade lasers,” International Microwave Symposium (IMS) 2012, WE3A-4, Montreal Canada, (June 2012). (Microwave Symposium Digest (MTT), 2012 IEEE MTT-S International  http://dx.doi.org/10.1109/MWSYM.2012.6259609)
  29. B. S. Williams, A. A. Tavallaee, P. W. C. Hon, Z. Liu, Q. Chen, T. Itoh, “Terahertz quantum cascade lasers and active metamaterial inspired waveguides,” International Microwave Symposium (IMS) 2012, WME workshop, Montreal Canada, (June 2012).
  30. B. S. Williams, A. A. Tavallaee, P. W. C. Hon, Zhijun Liu, Q. Chen, T. Itoh, “Terahertz active transmission-line metamaterial antennas,” 3rd International Conference on Metamaterials, Photonic Crystals and Plasmonics (META 2012), Paris, France, April 2012.
  31. B. S. Williams, Zhijun Liu, Philip W. C. Hon, Amir Ali Tavallaee, QiSheng Chen, Tatsuo Itoh “Terahertz composite right/left handed metamaterials,” Physics of Quantum Electronics 2012, Snowbird, Utah (January 2012).
  32. B. Benjamin S. Williams, Philip Hon, Amir Ali Tavallaee, Tatsuo Itoh, QiSheng Chen, “Terahertz QC-lasers and active metamaterial antennas,” 2011 SPIE Defense and Security Sensing (DSS), 25-29 April 2011, Orlando, FL.
  33. Benjamin S. Williams, Amir Ali Tavallaee, Karan Mehta, Philip Hon, Tatsuo Itoh, QiSheng Chen “Active Metamaterial Concepts for Terahertz Quantum-Cascade Lasers,” 2010 Workshop on Innovative Devices and Systems (WINDS), 5-10 December 2010, Kohala Coast, HI.
  34. Benjamin S. Williams, Amir Ali Tavallaee, Karan Mehta, Philip Hon, Tatsuo Itoh, “Terahertz quantum-cascade lasers and active terahertz metamaterials” Electrochemical Society (ECS) Meeting, October 2010, Las Vegas, NV.
  35. B. S. Williams, Zero-Index Terahertz Quantum-Cascade Metamaterial Lasers, International Quantum Cascade Lasers School & Workshop August 30-Sept. 3 2010, Florence Italy.
  36. S. Williams, “Terahertz quantum cascade lasers,” Asia Optical Fiber Communications & Optoelectronic Exposition & Conference (AOE 2008), Shanghai, China, October 2008.
  37. B. S. Williams, invited tutorial presentation on “Terahertz quantum cascade lasers”, GDR-E 2008 Terahertz Workshop, Paris, France, September 2008.
  38. B. S. Williams, “Terahertz quantum cascade lasers for local oscillators”, NASA SOFIA SSSC meeting, NASA Ames, Mountain View, CA August 28 2008.
  39. B. S. Williams, S. Kumar, Qi Qin, A. W. M. Lee, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers,” 2007 Conference on Lasers and Electro-optics (CLEO), Baltimore, MD (May 2007).
  40. B. S. Williams, S. Kumar, Qi Qin, A. W. M. Lee, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “High-temperature and high-power terahertz quantum cascade lasers,” SPIE’s Photonics West, San Jose, CA (January 2007).
  41. B. S. Williams, S. Kumar, Qi Qin, A. W. M. Lee, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers,” LEOS Annual Meeting 2006, Montreal, Canada (October 29-Nov 2, 2006).
  42. B. S. Williams, S. Kumar, Q. Qin, A. W. M. Lee, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers,” 2nd International Workshop on Quantum Cascade Lasers, Maria di Ostuni, Brindisi, Italy (September 6-9, 2006).
  43. B. S. Williams, S. Kumar, A. W. M. Lee, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers,” IEEE LEOS 2005 Terahertz Systems Workshop, Lexington, MA (November 9, 2005).
  44. B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers,” MIT Center for Integrated Photonic Systems (CIPS) Annual Meeting, Cambridge, MA (May 19-20, 2005).
  45. B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers,” SPIE’s Photonics West, San Jose, CA (January 2005).
  46. B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Resonant-phonon terahertz quantum-cascade lasers using metal-metal waveguides,” 2004 Joint 29th International Conference on Infrared and Millimeter Waves (IRMMW) and 12th International Conference on Terahertz Electronics (THZ), Karlsruhe, Germany (September 2004).
  47. B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascade lasers using resonant-phonon depopulation and metal-metal waveguides,” SPIE’s Photonics West, San Jose, CA (January 2004).
  48. B. S. Williams, H. Callebaut, Q. Hu, and J. L. Reno, “Development of THz quantum-cascade lasers,” Physics of Quantum Electronics 2003, Snowbird, Utah (January 2003).
  49. B. S. Williams, “Mixing of a passive scalar in two-dimensional turbulence,” 1997 APS/AAPT Joint Meeting, Washington, D.C. (April 1997).

Conference talks (contributed, speaker underlined)

*Undergraduate author

  1. Michael A. Schreiber, Yu Wu, Lukas Seitner, Johannes Stowasser, Michael Haider, Benjamin S. Williams, and Christian Jirauschek, “Modeling of RF-Modulated Metasurface Quantum Cascade External Cavity Lasers,” International Quantum Cascade Laser School and Workshop (IQCLSW) 2024, August 25-30 2024, Ischia, Italy.
  2. Anthony D. Kim, Daniel McGovern*, Benjamin S. Williams, “Self-Mixing Phenomena in THz metasurface QC-VECSELs,” International Quantum Cascade Laser School and Workshop (IQCLSW) 2024, August 25-30 2024, Ischia, Italy.
  3. Anthony Kim, M. Shahili, S. Addamane, C. A. Curwen, J. H. Kawamura, and B. S. Williams, “Metasurface-based terahertz quantum-cascade lasers operating beyond 5 THz,” 33nd IEEE International Symposium on Space THz Technology (ISSTT 2024), Charlottesville, Virginia, USA, April 7-11, 2024.
  4. Mohammad Shahili, Sadhvikas J. Addamane, Christopher Curwen, Jon Kawamura, and Benjamin S. Williams, “GaAs-based quantum cascade lasers for the 5-6 THz range,” Photonics West 2024, Feb 1 2024, San Francisco, CA.
  5. Anthony Kim, Daniel McGovern*, Sadhvikas J. Addamane, and Benjamin S. Williams, “Investigation of self-mixing in a THz quantum-cascade VECSEL under optical feedback,” Photonics West 2024, Feb 1 2024, San Francisco, CA.
  6. Yu Wu, Christopher A. Curwen, John L. Reno, Benjamin S. Williams, “RF injection locking of THz metasurface quantum-cascade-VECSEL: effect of cavity length variation,” Mid-Infrared Optoelectronics: Materials and Devices (MIOMD) 2023, Norman, OK, August 6-10, 2023. Received Best Student Presentation Award
  7. Christopher A. Curwen, Jonathan H. Kawamura, Darren J. Hayton, Sadhvikas J. Addamane, John L. Reno, Boris S. Karasik, and Benjamin S. Williams, “Stabilization of terahertz quantum-cascade VECSELs,” Mid-Infrared Optoelectronics: Materials and Devices (MIOMD) 2023, Norman, OK, August 6-10, 2023.
  8. Eilam Morag, Sandra Li*, Anthony D. Kim, Sadhvikas J. Addamane, Benjamin S. Williams, “Disordered metasurface quantum-cascade VECSELs,” Infrared Terahertz Quantum Workshop (ITQW), June 25-30, 2023, Erice, Italy.
  9. Mohammad Shahili, Sadhvikas J. Addamane, Benjamin S. Williams, “GaAs-based Quantum Cascade Laser Emitting above 5 THz,” Infrared Terahertz Quantum Workshop (ITQW), June 25-30, 2023, Erice, Italy. Received Best Paper Award.
  10. Boris Karasik, Chris Curwen, Daniel Cunnane, Jonathan Kawamura, Ke Chen, Xiaoxing Xi, Anthony Kim, Benjamin S. Williams, “Novel front-end for THz heterodyne system,” 2023 USNC-URSI National Radio Science Meeting (NRSM), January 10-14 2023, Boulder, CO.
  11. Eilam Morag, Sandra Li*, Anthony Kim, Sadhvikas J. Addamane, Benjamin S. Williams, “THz quantum-cascade VECSELs based upon disordered metasurfaces,” SPIE Photonics West 2023, January 28-February 2, 2023, San Francisco, CA.
  12. Yu Wu, Christopher A. Curwen, John L. Reno, Benjamin S. Williams, “RF injection locking of THz metasurface quantum-cascade-VECSEL,” SPIE Photonics West 2023, January 28-February 2, 2023, San Francisco, CA.
  13. Mohammad Shahili, Benjamin S. Williams, “Design strategies for GaAs-based THz quantum-cascade lasers in the 5-6 THz range,” SPIE Photonics West 2023, January 28-February 2, 2023, San Francisco, CA (poster).
  14. Anthony D. Kim, Yu Wu, Sadhvikas J. Addamane, Benjamin S. Williams, “Effects of output coupler on THz quantum-cascade VECSELs tunable between 2.5-3.0 THz,” SPIE Photonics West 2023, January 28-February 2, 2023, San Francisco, CA.
  15. Sidharth Thomas, Sam Razavian, Wei Sun, Anthony Kim, Yu Wu, Benjamin Williams, Aydin Babakhani, “Broadband 0.4-4 THz Generation in 90nm SiGe BiCMOS,” 2022 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), Phoenix, AZ, October 16-19, 2022.
  16. Christopher A. Curwen, Alain Maestrini, Anthony Kim, Sadhvikas J. Addamane, John L. Reno, Boris S. Karasik, Benjamin S. Williams, Jonathan H. Kawamura, “Phase-locking THz QC-VECSEL local oscillators using diode mixers and sources,” 31th IEEE International Symposium on Space Terahertz Technology (ISSTT 2022), Baeza, Andalusia (Spain), October 16-20 2022.
  17. Christopher A. Curwen, Daniel P. Cunnane, Jonathan H. Kawamura, Darren J. Hayton, Weibing Yang, Ke Chen, Xiaoxing Xi, Anthony D. Kim, Benjamin S. Williams, Boris S. Karasik, “Towards the THz heterodyne receiver for balloons and SmallSats above 2 THz,” 31th IEEE International Symposium on Space Terahertz Technology (ISSTT 2022), Baeza, Andalusia (Spain), October 16-20 2022.
  18. Christopher A. Curwen, Daniel P. Cunnane, Jonathan H. Kawamura, Darren J. Hayton, Weibing Yang, Ke Chen, Xiaoxing Xi, Anthony D. Kim, Benjamin S. Williams, Boris S. Karasik, “THz heterodyne system using novel mixer and local oscillator devices,” 47th International Conference on Infrared, Terahertz, and Millimeter Waves (IRMMW-THZ 2022).
  19. Christopher A. Curwen, Jonathan H. Kawamura, Darren J. Hayton, Yu Wu, Sadhvikas J. Addamane, John L. Reno, Benjamin S. Williams, Boris S. Karasik, “Terahertz quantum-cascade VECSELs local oscillators for heterodyne receivers,” SPIE Astronomical Telescopes + Instrumentation 2022 (ASTRO 2022), Montreal, CA, July 17-22, 2022.
  20. Yu Wu, Christopher Curwen, John L. Reno, and Benjamin S. Williams, “Continuous wave operation of terahertz metasurface quantum-cascade VECSEL with a long intra-cryostat cavity,” Conference on Lasers and Electro-Optics (CLEO 2022), San Jose, CA, May 16-20, 2022.
  21. Yue Shen, Anthony D. Kim, Mohammad Shahili, Christopher A. Curwen, Sadhvikas Addamane, John L. Reno, and Benjamin S. Williams, “Observation of Intersubband Polaritonic Coupling in a Quantum-Cascade Metasurface,” Conference on Lasers and Electro-Optics (CLEO 2022), San Jose, CA, May 16-20, 2022.
  22. Yu Wu, Sadhvikas Addamane, John L. Reno, and Benjamin S. Williams, “Multi-mode lasing in terahertz metasurface quantum-cascade VECSELs,” SPIE Photonics West 2022, January 22-29, 2022, San Francisco, CA.
  23. Yue Shen, Anthony D. Kim, Christopher A. Curwen, John L. Reno, and Benjamin S. Williams, “THz time-domain characterization of amplifying quantum cascade metasurface,” 45th International Conference on Infrared, Terahertz, and Millimeter Waves (IRMMW-THz 2020), Buffalo, NY, November 8-13, 2020.
  24. Christopher A. Curwen, Darren J. Hayton, Jonathan H. Kawamura, Boris S. Karasik, John L. Reno, and Benjamin S. Williams, “Phase locking of a THz QC-VECSEL,” International Quantum Cascade Laser School and Workshop (IQCLSW 2020), September 7-10 2020, Monte Verita, Switzerland. (Poster)
  25. Anthony D. Kim, Luyao Xu, Christopher A. Curwen, Daguan Chen*, John L. Reno, and Benjamin S. Williams, “Cavity length dependence of a metasurface quantum-cascade laser with electrically switchable polarization,” OSA Optical Sensors and Sensing Congress, Vancouver, Canada, June 22-26, 2020.
  26. Jonathan Kawamura, Daniel Cunnane, Boris Karasik, Bruce Bumble, Darren Hayton, Jacob Kooi, Imran Mehdi, Goutam Chattopadhyay, Maria Alonso, Jose Siles, Christopher Curwen, and Benjamin Williams, “Development of THz Superconducting HEB Receiver Systems for Balloons, Aircraft, SmallSats, and Future Large Missions,” 31th IEEE International Symposium on Space Terahertz Technology (ISSTT 2020), Tempe, AZ, March 8-11 2020. (Poster)
  27. Christopher A. Curwen, John L. Reno, and Benjamin S. Williams, “Low-power consumption THz quantum-cascade VECSEL using patch-based metasurface,” 31th IEEE International Symposium on Space Terahertz Technology (ISSTT 2020), Tempe, AZ, March 8-11 2020.
  28. Yue Shen, Christopher Curwen, Luyao Xu, and Benjamin S. Williams, “THz time-domain characterization of amplifying quantum cascade metasurface,” Infrared Terahertz Quantum Workshop (ITQW 2019), Ojai, CA Sept 15-20 2019.
  29. Anthony Kim, Christopher Curwen, Luyao Xu, John Reno, and Benjamin Williams, “Terahertz polarization imaging using quantum cascade laser,” Infrared Terahertz Quantum Workshop (ITQW 2019), Ojai, CA Sept 15-20 2019. (poster presentation)
  30. Christopher A. Curwen, Luyao Xu, John L. Reno, and Benjamin S. Williams, “Resonant patch metasurface for continuous wave operation of terahertz quantum-cascade VECSEL,” Optical Terahertz Science and Technology (OTST), March 10-15 2019, Santa Fe, NM. (poster presentation)
  31. Christopher A. Curwen, John L. Reno, and Benjamin S. Williams, “Short-cavity THz QC-VECSEL with 20% fractional tuning,” SPIE Photonics West 2019, February 2-7 2019, San Francisco, CA.
  32. Christopher A. Curwen, John L. Reno, Benjamin S. Williams, “High power terahertz quantum-cascade VECSEL,” International Quantum Cascade Laser School and Workshop, Cassis France, September 2-7, 2018.
  33. Christopher A. Curwen, John L. Reno, Tatsuo Itoh, Benjamin S. Williams, “Broadband metasurface external-cavity QC-lasers,” 29th IEEE International Symposium on Space Terahertz Technology (ISSTT 2018), Pasadena, CA, March 26-28 2018.
  34. Benjamin A. Burnett, Andrew Pan, and Benjamin S. Williams, “Reliable density matrix modeling of THz QCL active regions from the energy eigenbasis,” Intersubband Transitions in Quantum Wells (ITQW), September 2017, Singapore. (poster presentation)
  35. R. Al Hadi, Y. Zhao, Y. Li, Y. Du, C. Curwen, M. K. Lo, B. S. Williams, and M.-C. F. Chang, “Multi-Spectral Terahertz Interferometric Imaging Based on a Monolithic Retroactive Silicon Chip,” 2017 IEEE International Conference on Microwaves, Antennas, Communications and Electronic Systems (COMCAS). 13-15 Nov. 2017. Tel Aviv, Israel. (https://doi.org/10.1109/COMCAS.2017.8244849 )
  36. C. A. Curwen, L. Xu, J. L. Reno, T. Itoh, and B. S. Williams, “Broadband continuous tuning of a THz quantum-cascade VECSEL,” Conference on Lasers and Electro-Optics (CLEO 2017), San Jose, CA. STh4O.2
  37. D. Chen*, L. Xu, C. A. Curwen, M. Memarian, J. L. Reno, T. Itoh, and B. S. Williams, “Metasurface terahertz laser with electronically controlled polarization,” Conference on Lasers and Electro-Optics (CLEO 2017), San Jose, CA. FTu4G.5
  38. L. Xu, C. A. Curwen, D. Chen*, T. Itoh, J. Reno, and B. S. Williams, “Focusing Metasurface Quantum-Cascade VECSEL,” Conference on Lasers and Electro-Optics (CLEO 2017), San Jose, CA. SW1C.1
  39. Dingkun Ren, Alan C. Farrell, Xiao Meng, Benjamin S. Williams, and Diana L. Huffaker, “Selective-area InAs-based Nanowires on InP Substrates Towards SWIR/Mid-IR Optical Devices,” Materials Research Society Fall Meeting (MRS 2016), Nov 27-Dec 2, 2016, Boston, MA.
  40. L. Xu, C. Curwen, Q.-S. Chen, J. Reno, T. Itoh, B. S. Williams, “Metasurface quantum-cascade VECSELs from 2.5-3.5 THz,” International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW/THz 2016), September 25-30 2016, Copenhagen, Denmark.
  41. Andrew Pan, Benjamin A. Burnett, and Benjamin S. Williams, “Modeling coherent transport in QCLs without an artificially localized basis,” International Quantum Cascade Laser School and Workshop (IQCLSW 2016), September 4-9 2016, Cambridge, UK (poster presentation).
  42. R. Al Hadi, Y. Zhao, Y. Li, Y. Du, C. Curwen, B. S. Williams, and M.-C. F. Chang, “A Spectral Profiling Method of mm-Wave and Terahertz Radiation Sources,” International Microwave Symposium (IMS 2016) San Francisco, CA, May 22-27 2016. https://doi.org/10.1109/MWSYM.2016.7540264
  43. Luyao Xu, Christopher A. Curwen, Philip W. C. Hon, Tatsuo Itoh, and Benjamin S. Williams, “Terahertz quantum cascade VECSEL” SPIE Photonics West 2016, San Francisco, February 13-18 2016. (Received Best Student Presentation Award) (Proc SPIE 9734   http://dx.doi.org/10.1117/12.2213230  )
  44. Benjamin Burnett and Benjamin Williams, “Polaron effects in terahertz quantum dot cascade lasers” Intersubband Transitions in Quantum Wells (ITQW) 2015, Vienna Austria, September 6-11 2015.
  45. Benjamin Burnett and Benjamin Williams, “Density matrix modeling of terahertz difference frequency generation in dual active-region quantum cascade lasers,” Intersubband Transitions in Quantum Wells (ITQW) 2015, Vienna Austria, September 6-11 2015 (poster presentation).
  46. Benjamin Burnett, Andrew Lin, Diana Huffaker, and Benjamin Williams, “Towards Intersubband nanowire photonics,” Intersubband Transitions in Quantum Wells (ITQW) 2013, Bolton Landing, NY, September 16-20 2013 (poster presentation).
  47. Amir Ali Tavallaee, Philip Hon, Qi-Sheng Chen, Tatsuo Itoh, and Benjamin Williams, “Terahertz Quantum-Cascade Lasers based on Composite Right/Left-Handed Metamaterials,” 2013 2012 Conference on Lasers and Electro-optics (CLEO), CTu1J.2, San Jose, CA June 10-14 2013.
  48. Philip Hon, Amir Tavallaee, Zhijun Liu, Benjamin Williams, Tatsuo Itoh, “Radiation Modeling of Terahertz Transmission-Line Metamaterial,” 2012 Conference on Lasers and Electro-optics (CLEO), QTu3F.8, San Jose, CA (May 6-11 2012).
  49. Zhijun Liu, Philip Hon, Amir Tavallaee, Tatsuo Itoh, and Benjamin Williams, “Terahertz composite right/left-handed transmission-line metamaterial surfaces,” American Physical Society March Meeting, Boston, MA (Feb 27-Mar 2 2012).
  50. Amir Tavallaee, Benjamin Williams, Philip Hon, Tatsuo Itoh, Qi-Sheng Chen, “An active terahertz quantum-cascade metamaterial antenna,” Intersubband Transitions in Quantum Wells (ITQW) 2011, Sardinia, Italy, September 11-17 2011.
  51. Amir Tavallaee, Matthew Puckett*, Benjamin Williams, Philip Hon, Tatsuo Itoh, Qi-Sheng Chen, “A Terahertz Quantum-Cascade Laser with an Active Leaky-Wave Metamaterial Antenna,” 2011 Conference on Lasers and Electro-optics (CLEO), CThE1, Baltimore, MD (May 1-6 2011).
  52. Amir Ali Tavallaee, Karan Mehta*, Benjamin S. Williams, Philip Hon, and Tatsuo Itoh, “Feasibility of a Terahertz Quantum Cascade Active Metamaterial Based on Composite Right/Left-Handed Transmission-Lines,” Intersubband Transitions in Quantum Wells (ITQW) 2009, Montreal Canada, September 7-11.
  53. Aaron Wade, Georgy Fedorov, Dmitry Smirnov, Benjamin S. Williams, Sushil Kumar, Qing Hu, John L. Reno, “High Temperature, Magnetic Field Assisted (sub)THz Quantum Cascade Laser,” Thursday, Jun 04, 2009, CThT6, CLEO 2009
  54. Allen L. Hsu, Qing Hu, Benjamin WilliamsFour-Well Highly Strained Quantum Cascade Lasers Grown by Metal-Organic Chemical Vapor Deposition,” Thursday, Jun 04, 2009, CLEO 2009
  55. B. S. Williams, S. Kumar, Q. Qin, Q. Hu, and J. L. Reno, “High-power terahertz quantum cascade lasers,” 2006 Conference on Lasers and Electro-optics (CLEO), Long Beach, CA (May 2006).
  56. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “High-temperature performance of terahertz quantum-cascade lasers,” 8th International Conference on Intersubband Transitions in Quantum Wells (ITQW), Cape Cod, MA (Sept. 2005).
  57. B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Advances in terahertz quantum-cascade lasers using metal-metal waveguides,” 2005 Optical Terahertz Science and Technology (OTST), Orlando, FL (March 2005).
  58. B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Resonant-phonon terahertz quantum cascade lasers at long wavelengths,” 2003 Conference on Lasers and Electro-optics (CLEO), Baltimore, MD (June 2003).
  59. B. S. Williams, S. Kumar, H. Callebaut, Q. Hu, and J. L. Reno, “Terahertz quantum cascade laser based on resonant-phonon depopulation and using metal-metal waveguides,” 7th International Conference on Intersubband Transitions in Quantum Wells (ITQW), Evolène, Switzerland (Sept. 2003).
  60. B. S. Williams, H. Callebaut, S. Kumar, Q. Hu, and J. L. Reno, “Terahertz quantum cascade laser based on LO-phonon-scattering assisted depopulation,” 2003 Conference on Lasers and Electro-optics (CLEO), Baltimore, MD (June 2003).
  61. B. S. Williams, H. Callebaut, S. Kumar, Q. Hu, and J. L. Reno, “Terahertz quantum cascade laser based on direct LO-phonon-scattering depopulation,” 2003 APS March Meeting, Austin, TX (March 2003).
  62. B. S. Williams, Hans Callebaut, Q. Hu, M. R. Melloch, and J. L. Reno, “Terahertz intersubband emission in structures with and without LO-phonon assisted depopulation,” 6th International Conference on Intersubband Transitions in Quantum Wells (ITQW), Asilomar, California (Sept 2001).
  63. B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, “Narrow-linewidth interwell THz intersubband emission,” 8th International Conference on Terahertz Electronics, Darmstadt, Germany (September 2000).
  64. B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, “Narrow linewidth terahertz intersubband emission from three-level multiple quantum well structures,” 5th International Conference on Intersubband Transitions in Quantum Wells (ITQW), Bad Ischl, Austria (Sept 1999).
  65. B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, “Terahertz intersubband emission from cascaded multiple quantum well structures,” SPIE’s International Symposium on Optical Science, Engineering, and Instrumentation, Denver, CO (July 1999).
  66. B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, “Narrow linewidth terahertz intersubband emission,” 1999 APS March Meeting, Atlanta, GA (March 1999).
  67. B. S. Williams, B. Riely, Q. Hu, and M. R. Melloch, “Mid-infrared GaAs/AlGaAs based quantum cascade emitters,” TMS 40th Electronic Materials Conference, Charlottesville, VA (June 1998).
  68. B. S. Williams, B. Riely, Q. Hu, and M. R. Melloch, “Mid-infrared quantum cascade lasers,” 1998 APS March Meeting, Los Angeles, CA (March 1998).