Coherent sensing

Frequency combs and other coherent light sources can be used to perform unique types of sensing, and one theme of our work is to use these devices for this purpose. For example, the dual comb spectroscopy technique allows for the creation of high-speed spectrometers with no moving parts, allowing for the creation of sensors that are ultra-compact. They also have applications in remote sensing, astronomy, and quantum sensing.

Terahertz dual comb spectroscopy with quantum cascade laser frequency combs. Two combs are shined onto a detector, and optical frequencies are converted into radio frequencies. This allows for electrical measurements to replace optical measurements. [2]

Hyperspectral imaging with our terahertz combs, performed by the Wysocki group at Princeton [1]. Because spectra can be acquired extremely with a dual comb technique, one can use these combs to determine the different components of a pill that is completely white.


  1. L.A. Sterczewski, J. Westberg, Y. Yang, D. Burghoff, J. Reno, Q. Hu, and G. Wysocki, “Terahertz Spectroscopy of Gas Mixtures with Dual Quantum Cascade Laser Frequency Combs,” ACS Photonics, vol. 7, no. 5, pp. 1082–1087, May 2020. (link)
  2. L. A. Sterczewski, J. Westberg, Y. Yang, D. Burghoff, J. Reno, Q. Hu, and G. Wysocki, “Terahertz hyperspectral imaging with dual chip-scale combs,” Optica, vol. 6, no. 6, pp. 766–771, Jun. 2019. (link)
  3. Yang Yang, David Burghoff, Darren J. Hayton, Jian-Rong Gao, John L. Reno, and Qing Hu, “Terahertz multiheterodyne spectroscopy using laser frequency combs,” Optica, 3, 499 (2016). (pdf, supplementary, Special Collection on Frequency Combs)
  4. A. Wei Min Lee, T.-Y. Kao, D. Burghoff, Q. Hu, and J. L. Reno, “Terahertz tomography using quantum-cascade lasers,” Opt. Lett., vol. 37, no. 2, pp. 217–219, Jan. 2012. (link)