Room Temperature, High Power, Monolithic Optical THz Source Based on Photonic Crystal Distributed Feedback Quantum Cascade Lasers

Northwestern University, Evanston IL

Investigators

Abstract

Objective The aim is to create a revolutionary monolithic, narrow linewidth, THz technology which is compact, mass-producible, and has mW-scale power output at room temperature. This will be achieved by optimizing intrinsic nonlinearities in quantum cascade lasers, reducing absorption and phase-matching losses, improving pump power and spectral purity, and improving the device geometry for better THz outcoupling. Intellectual Merit The proposed effort combines basic science with advanced technology in order to produce a multi-component, yet highly integrated and functional, device. The building blocks of the high power THz source represent many active areas of investigation including: high power, dual frequency quantum cascade lasers based on two-dimensional diffractive feedback, band structure engineering of nonlinearity in a quantum system, and investigation of plasmon waveguides and surface gratings. The proposed research also makes an excellent case study for how theory, technology, and experiment all play a role in developing a single integrated device. Broader Impact This proposal addresses critical needs in the field of THz light generation at room temperature. There is also significant potential for follow-on work to explore electrical tunability of the source. Besides improving spectroscopy and imaging efforts, the biggest impact of a compact, mass-producible THz source will be ease of access, which will enable new research and applications to be developed in diverse fields. To increase the lasting impact of this work, educational and outreach activities are stressed which include hands-on training of undergraduates and high-school students.