Benjamin S. Williams - UCLA Engineering

Benjamin S. WilliamsUniversity of California at Los Angeles (UCLA)bwilliam@ee.ucla.eduDepartment of Electrical Engineeringwww.ee.ucla.edu/faculty/bios/williams.htmCalifornia NanoSystems Institute (CNSI) Phone: (310) 825-696168-117 Engineering IV Bldg420 Westwood PlazaBox 951594Los Angeles, CA 90095-1594ResearchInterestsQuantum cascade lasers for the terahertz and mid-infraredDevelopment of terahertz QCLs for higher temperature operation, lower frequencies, higher efficiencies,improved beam pattern and spectral purity. Development of mid-IR QCLs for high-power and high wallplugefficiencies. Terahertz science, imaging, chemical and biological sensing, and detection.Sub-wavelength terahertz plasmonics and metamaterials: active metamaterials, sub-wavelength metalterahertz waveguides, distributed feedback structures, structured metallic surfaces, photonic/ plasmoniccrystals, surface plasmon enhanced sensing, transmission through and emission from sub-wavelengthaperturesLow-dimensional nanostructures for optoelectronic applications: quantum wells, semiconductorintersubband (intraband) transport and physics, semiconductor heterostructure nanowires, quantum wiresand dots, nano-lasers, inter-sublevel physicsEducation Massachusetts Institute of Technology Cambridge, MAPh.D. in Electrical Engineering and Computer Science, September 2003.Thesis: Terahertz quantum cascade lasers.Massachusetts Institute of TechnologyM. S. in Electrical Engineering and Computer Science, May 1998.Thesis: GaAs/AlGaAs Mid-Infrared Quantum Cascade Lasers.Haverford CollegeB. S. with high honors in Physics, May 1996.Thesis: Mixing of a passive scalar in two-dimensional turbulence.Cambridge, MAHaverford, PACareer Assistant Professor, UCLA, Department of Electrical Engineering January 2007-presentHistoryPostdoctoral Associate, MIT, Research Laboratory of Electronics October 2003-October 2006Technical Achievements: Demonstrated record maximum operating temperatures of 169 K (pulsed) and117 K (continuous-wave) of THz QC-lasers, and extended operating frequencies from 1.7–5.0 THz (60–180 m) through novel quantum-cascade designs and improvements in waveguide fabrication technology.Demonstrated single-mode laterally-corrugated distributed feedback lasers. Developed high power THzlaser with up to 248 mW output power used for real-time video-rate terahertz imaging.Research Assistant (Ph.D.), MIT, Dept. EECS August 1998-August 2003Technical Achievements: Developed terahertz semiconductor quantum cascade laser (QCL) based onnovel resonant-phonon depopulation scheme for use in underutilized terahertz spectral regime.Demonstrated metal-metal waveguide for first time in terahertz QCLs, which has proven critical in hightemperaturelaser operation. THz lasers based upon these achievements hold current records for highpoweroperation and high-temperature operation.Awards DARPA Young Faculty Award (2008)

Professor Benjamin S. Williams, UCLACVS. Kumar, B. S. Williams, Qi Qin, A. W. M. Lee, Q. Hu and J. L. Reno, “Surface-emitting distributedfeedback terahertz quantum-cascade lasers in metal-metal waveguides.” Optics Express, vol. 15, 8January 2007, pp. 113. http://www.opticsinfobase.org/abstract.cfm?URI=oe-15-1-113A. W. M. Lee, Qi Qin, S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “Real-time terahertz imagingover a standoff distance (>25 meters).” Applied Physics Letters, vol. 89, 2 October 2006, pp. 141125.http://link.aip.org/link/?APPLAB/89/141125/1A. 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 quantumcascade 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)B. S. Williams, S. Kumar, Q. Qin, Q. Hu and J. L. Reno, “Terahertz quantum-cascade lasers with doubleresonant-phonon depopulation.” Applied Physics Letters, vol. 88, 26 June 2006, pp. 261101.http://link.aip.org/link/?APPLAB/88/261101/1A. W. M. Lee, B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Real-time imaging using a 4.3-THzquantum 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.2006.877220E. 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)A. 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 subwavelengthcavity dimensions.” Applied Physics Letters. 88, no. 15, 10 April 2006, pp. 151105.http://link.aip.org/link/?APPLAB/88/151105/1(Reprinted in Virtual Journal of Nanoscale Science and Technology)S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “1.9-THz quantum-cascade lasers with one-wellinjector.” Applied Physics Letters, vol. 88, no. 12, 20 March 2006, pp. 121123.http://link.aip.org/link/?APPLAB/88/121123/1B. 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:20063921B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Distributed-feedback terahertz quantum-cascade laserswith laterally corrugated metal waveguides.” Optics Letters, vol. 30, no. 21, November 2005, pp. 2909.http://www.opticsinfobase.org/abstract.cfm?URI=ol-30-21-2909H. 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-cascadelasers.” Applied Physics Letters, vol. 87, 3 October 2005, pp. 141102.http://link.aip.org/link/?APPLAB/87/141102/1Q. Hu, B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, and J. L. Reno, “Resonant-phonon-assistedTHz 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- 3 -

Professor Benjamin S. Williams, UCLACVA. L. Betz, R. T. Boreiko, B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Frequency and phase-lockcontrol 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-30-14-1837J. 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 heterodynereceiver 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(Reprinted in Virtual Journal of Nanoscale Science and Technology)B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Operation of terahertz quantum-cascade lasers at 164 Kin pulsed mode and 117 K in continuous-wave mode.” Optics Express, vol. 13, no. 9, 3 May 2005, pp.3331. (Reprinted in Virtual Journal of Nanoscale Science and Technology)http://www.opticsinfobase.org/abstract.cfm?URI=oe-13-9-3331M. 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-cascadelasers.” Applied Physics Letters, vol. 86, no. 11, 14 Mar. 2005, pp. 111115.http://link.aip.org/link/?APPLAB/86/111115/1S. Kohen, B. S. Williams, and Q. Hu, “Electromagnetic modeling of terahertz quantum cascade laserwaveguides and resonators.” Journal of Applied Physics, vol. 97, no. 5, 1 Mar. 2005, pp. 053106.http://link.aip.org/link/?JAPIAU/97/053106/1B. S. Williams, S. Kumar, Q. Hu and J. L. Reno, “Resonant-phonon terahertz quantum-cascade laseroperating at 2.1 THz ( 141 m).” Electronics Letters, vol. 40, no. 7, 1 Apr. 2004, pp. 431-2.S. Kumar, B. S. Williams, S. Kohen, Q. Hu, and J. L. Reno, “Continuous-wave operation of terahertzquantum-cascade lasers above liquid-nitrogen temperature.” Applied Physics Letters, vol. 84, no. 14, 5Apr. 2004, pp. 2494-6. http://link.aip.org/link/?APPLAB/84/2494/1Q. Hu, B. S. Williams, S. Kumar, H. Callebaut, and J. L. Reno, “Terahertz quantum-cascade lasers basedon resonant phonon scattering for depopulation.” Philosophical Transactions of the Royal Society ofLondon A, vol. 362, 2004, pp. 233-49.H. Callebaut, S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “Importance of electron-impurityscattering for electron transport in terahertz quantum cascade lasers.” Applied Physics Letters, vol. 84,no. 5, 2 Feb. 2004, pp. 645-7. http://link.aip.org/link/?APPLAB/84/645/1B. S. Williams, S. Kumar, H. Callebaut, Q. Hu and J. L. Reno, “Terahertz quantum-cascade laseroperating up to 137 K.” Applied Physics Letters, vol. 83, no. 25, 22 Dec. 2003, pp. 5142-4.B. S. Williams, S. Kumar, H. Callebaut, Q. Hu and J. L. Reno, “Terahertz quantum-cascade laser at 100 m using metal waveguide for mode confinement.” Applied Physics Letters, vol. 83, no. 11, 15 Sept.2003, pp. 2124-6. http://link.aip.org/link/?APPLAB/83/2124/1H. Callebaut, S. Kumar, B. S. Williams, Q. Hu and J. L. Reno, “Analysis of transport properties ofterahertz quantum cascade lasers.” Applied Physics Letters, vol. 83, no. 2, 14 Jul. 2003, pp. 207-9.http://link.aip.org/link/?APPLAB/83/207/1B. S. Williams, S. Kumar, H. Callebaut, Q. Hu and J. L. Reno, “3.4 THz quantum cascade laser operatingabove liquid nitrogen temperature.” Electronics Letters, vol. 39, no. 12, 12 Jun. 2003, pp. 915-6.B. S. Williams, H. Callebaut, S. Kumar, Q. Hu and J. L. Reno, “3.4-THz quantum cascade laser based onlongitudinal-optical-phonon scattering for depopulation.” Applied Physics Letters, vol. 82, no. 7, 17 Feb.2003, pp. 1015-7. http://link.aip.org/link/?APPLAB/82/1015/1- 4 -

Professor Benjamin S. Williams, UCLACVQ. Hu, B. S. Williams, M. R. Melloch, and J. L. Reno, “Terahertz emitters based on intersubbandtransitions.” In Future Trends in Microelectronics, Wiley, New York, pp. 242-52B. S. Williams, H. Callebaut, Q. Hu, and J. L. Reno, "Magnetotunneling spectroscopy of resonantanticrossing in terahertz intersubband emitters." Applied Physics Letters, vol.79, no.26, 24 Dec. 2001, pp.4444-6. (Reprinted in Virtual Journal of Nanoscale Science and Technology)http://link.aip.org/link/?APPLAB/79/4444/1B. S. Williams, Q. Hu, "Optimized energy separation for phonon scattering in three-level terahertzintersubband lasers." Journal of Applied Physics, vol.90, no.11, 1 Dec. 2001, pp.5504-11.B. S. Williams, B. Xu, Q. Hu, M. R. Melloch, "Narrow linewidth terahertz intersubband emission fromthree-level systems." Applied Physics Letters, vol. 75, no 19, 8 Nov. 1999, pp. 2927-9.http://link.aip.org/link/?APPLAB/75/2927/1B. S. Williams, D. Marteau, J. P. Gollub, "Mixing of a passive scalar in magnetically forced twodimensionalturbulence." Physics of Fluids, vol.9, no.7, July 1997, pp.2061-80.Invited TalksB. S. Williams, “Terahertz quantum cascade lasers,” Asia Optical Fiber Communications &Optoelectronic Exposition & Conference (AOE 2008), Shanghai, China, October 2008.B. S. Williams, invited tutorial presentation on “Terahertz quantum cascade lasers”, GDR-E 2008Terahertz Workshop, Paris, France, September 2008.B. S. Williams, “Terahertz quantum cascade lasers for local oscillators”, NASA SOFIA SSSC meeting,NASA Ames, Mountain View, CA August 28 2008.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).B. S. Williams, S. Kumar, Qi Qin, A. W. M. Lee, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Hightemperatureand high-power terahertz quantum cascade lasers,” SPIE’s Photonics West, San Jose, CA(January 2007).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).B. S. Williams, S. Kumar, Q. Qin, A. W. M. Lee, Q. Hu, and J. L. Reno, “Terahertz quantum cascadelasers,” 2 nd International Workshop on Quantum Cascase Lasers, Maria di Ostuni, Brindisi, Italy(September 6-9, 2006).B. S. Williams, S. Kumar, A. W. M. Lee, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertzquantum cascade lasers,” IEEE LEOS 2005 Terahertz Systems Workshop, Lexington, MA (November 9,2005).B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascadelasers,” MIT Center for Integrated Photonic Systems (CIPS) Annual Meeting, Cambridge, MA (May 19-20, 2005).B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascadelasers,” SPIE’s Photonics West, San Jose, CA (January 2005).- 5 -

Professor Benjamin S. Williams, UCLACVB. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Resonant-phonon terahertzquantum-cascade lasers using metal-metal waveguides,” 2004 Joint 29 th International Conference onInfrared and Millimeter Waves (IRMMW) and 12 th International Conference on Terahertz Electronics(THZ), Karlsruhe, Germany (September 2004).B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Terahertz quantum cascadelasers using resonant-phonon depopulation and metal-metal waveguides,” SPIE’s Photonics West, SanJose, CA (January 2004).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).B. S. Williams, "Mixing of a passive scalar in two-dimensional turbulence," 1997 APS/AAPT JointMeeting, Washington, D.C. (April 1997).Conference talks (contributed)Amir Ali Tavallaee, Karan Mehta, Benjamin S. Williams, Philip Hon, and Tatsuo Itoh, “Feasibility of aTerahertz Quantum Cascade Active Metamaterial Based on Composite Right/Left-Handed Transmission-Lines,” Intersubband Transitions in Quantum Wells (ITQW) 2009, Montreal Canada, September 7-11.Aaron Wade 1 , Georgy Fedorov 1 , Dmitry Smirnov 1 , Benjamin S. Williams 2 , Sushil Kumar 3 , Qing Hu 3 , John L.Reno, High Temperature, Magnetic Field Assisted (sub)THz Quantum Cascade Laser Thursday, Jun04, 2009, CThT6, CLEO 2009Allen L. Hsu, Qing Hu, Benjamin Williams Four-Well Highly Strained Quantum Cascade Lasers Grownby Metal-Organic Chemical Vapor Deposition Thursday, Jun 04, 2009, CLEO 2009B. S. Williams, S. Kumar, Q. Qin, Q. Hu, and J. L. Reno, “High-power terahertz quantum cascadelasers,” 2006 Conference on Lasers and Electro-optics (CLEO), Long Beach, CA (May 2006).B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “High-temperature performance of terahertz quantumcascadelasers,” 8 th International Conference on Intersubband Transitions in Quantum Wells (ITQW),Cape Cod, MA (Sept. 2005).B. S. Williams, S. Kumar, H. Callebaut, S. Kohen, Q. Hu, and J. L. Reno, “Advances in terahertzquantum-cascade lasers using metal-metal waveguides,” 2005 Optical Terahertz Science and Technology(OTST), Orlando, FL (March 2005).B. S. Williams, S. Kumar, Q. Hu, and J. L. Reno, “Resonant-phonon terahertz quantum cascade lasers atlong wavelengths,” 2003 Conference on Lasers and Electro-optics (CLEO), Baltimore, MD (June 2003).B. S. Williams, S. Kumar, H. Callebaut, Q. Hu, and J. L. Reno, “Terahertz quantum cascade laser basedon resonant-phonon depopulation and using metal-metal waveguides,” 7 th International Conference onIntersubband Transitions in Quantum Wells (ITQW), Evolène, Switzerland (Sept. 2003).B. S. Williams, H. Callebaut, S. Kumar, Q. Hu, and J. L. Reno, “Terahertz quantum cascade laser basedon LO-phonon-scattering assisted depopulation,” 2003 Conference on Lasers and Electro-optics (CLEO),Baltimore, MD (June 2003).B. S. Williams, H. Callebaut, S. Kumar, Q. Hu, and J. L. Reno, “Terahertz quantum cascade laser basedon direct LO-phonon-scattering depopulation,” 2003 APS March Meeting, Austin, TX (March 2003).B. S. Williams, Hans Callebaut, Q. Hu, M. R. Melloch, and J. L. Reno, "Terahertz intersubband emissionin structures with and without LO-phonon assisted depopulation," 6th International Conference onIntersubband Transitions in Quantum Wells (ITQW), Asilomar, California (Sept 2001).- 6 -

Professor Benjamin S. Williams, UCLACVB. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, "Narrow-linewidth interwell THz intersubbandemission," 8 th International Conference on Terahertz Electronics, Darmstadt, Germany (September 2000).B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, "Narrow linewidth terahertz intersubband emissionfrom three-level multiple quantum well structures," 5th International Conference on IntersubbandTransitions in Quantum Wells (ITQW), Bad Ischl, Austria (Sept 1999).B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, "Terahertz intersubband emission from cascadedmultiple quantum well structures," SPIE's International Symposium on Optical Science, Engineering, andInstrumentation, Denver, CO (July 1999).B. S. Williams, B. Xu, Q. Hu, and M. R. Melloch, "Narrow linewidth terahertz intersubband emission,"1999 APS March Meeting, Atlanta, GA (March 1999).B. S. Williams, B. Riely, Q. Hu, and M. R. Melloch, "Mid-infrared GaAs/AlGaAs based quantum cascadeemitters," TMS 40th Electronic Materials Conference, Charlottesville, VA (June 1998).B. S. Williams, B. Riely, Q. Hu, and M. R. Melloch, "Mid-infrared quantum cascade lasers," 1998 APSMarch Meeting, Los Angeles, CA (March 1998).- 7 -