Society of Optics Student Chapter Seminar

Title: Novel Techniques of External Cavity Control for Quantum Cascade Lasers

Abstract: Quantum Cascade Lasers (QCLs) are a useful source of mid-infrared laser radiation for spectroscopic applications. Since the invention of QCLs 30 years ago and the invention of QCL frequency combs approximately 10 years ago, the implementation of new technologies to
better leverage QCL performance and improve the their control is an active area of research. One powerful technique to control QCLs is by external cavity (EC) optical feedback injection. In this method, photons emitted from a laser are subject to selection by an external cavity and are subsequently fed back to the laser to seed the generation of new photons. This talk will discuss two EC-QCL technologies: one which enables an ultra-broadband laser spectrometer for planetary science applications, and another which has allowed controlled harmonic comb generation in QCL frequency combs. To complement this technical talk, Nick will also provide remarks on his experiences in graduate school as an undergraduate alumni of CREOL.

About the speaker: Nick Kosan received his Bachelor’s degree at CREOL in 2019 (summa cum
laude). Currently, he is a Ph.D candidate at Princeton University’s Department of Electrical and Computer Engineering under the supervision of Professor Gerard Wysocki. Nick’s doctoral studies are supported by the NASA Space Technology Graduate Research Opportunities fellowship. His research focuses on laser spectroscopy systems with both single mode and frequency comb QCLs. As a visiting scholar, Nick continued these research efforts at Southwest Research Institute and
ETH Zürich. In addition to his research responsibilities, Nick serves as the Vice President of Internal Affairs of Princeton’s Graduate Student Government.