Terahertz and mid-infrared quantum cascade lasers and photonic devices, low-dimensional semiconductor materials and intersubband physics, metamaterial waveguides, antennas, and metasurfaces in the terahertz and infrared

• 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
• B. A. Burnett and B. S. Williams, “Density matrix model for polarons in a terahertz quantum dot cascade laser,” Phys. Rev. B, vol 90, 155309, 2014.
• 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.
• 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.  Winner of 2013 IEEE Transactions on THz Science and Technology Best Paper Award.
• Benjamin S. Williams, “Terahertz quantum cascade lasers.” Nature Photonics, vol. 1, September 2007, pp. 517-525. (review article)
• 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.
• 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)

• 2016, Presidential Early Career Award for Scientists and Engineers (PECASE)
• 2012, National Science Foundation CAREER Award
• 2008, DARPA Young Faculty Award (YFA)