Terahertz physics

The terahertz frequency range falls between 0.3-10 THz and represents an underutilized part of the electromagnetic spectrum. In particular, light in the 2-10 THz range is difficult to generate, as parasitics negatively impact high-frequency electronics and conventional laser sources do not operate in this range. Our research in this area uses a combination of terahertz quantum cascade lasers and terahertz time-domain spectroscopy to study the physics of various systems, including quantum cascade lasers and topological insulators.

Example of a time-domain terahertz pulse. When it is transmitted through a sample, its amplitude and phase are modified.

Schematic of an integrated photoconductive antenna integrated into a quantum cascade laser, used to measure the QCL’s dispersion and gain.

One of our current directions: optical-pump-terahertz-probe studies of topological insulator heterostructures


  1. D. Burghoff, Y. Yang, J. L. Reno, and Q. Hu, “Dispersion dynamics of quantum cascade lasers,” Optica, vol. 3, no. 12, p. 1362, Dec. 2016. (pdf, supplementary)
  2. D. Burghoff, C. Wang Ivan Chan, Q. Hu, and J. L. Reno, “Gain measurements of scattering-assisted terahertz quantum cascade lasers,” Appl. Phys. Lett., vol. 100, no. 26, p. 261111, Jun. 2012. (pdf)
  3. D. Burghoff, T.-Y. Kao, D. Ban, A. W. M. Lee, Q. Hu, and J. Reno, “A terahertz pulse emitter monolithically integrated with a quantum cascade laser,” Appl. Phys. Lett., vol. 98, no. 6, p. 061112, Feb. 2011. (pdf)