Applied Physics B

, Volume 100, Issue 2, pp 243–251

External-cavity quantum cascade lasers with fast wavelength scanning


DOI: 10.1007/s00340-009-3865-5

Cite this article as:
Tsai, T. & Wysocki, G. Appl. Phys. B (2010) 100: 243. doi:10.1007/s00340-009-3865-5


Fast wavelength scanning of an external-cavity quantum cascade laser (EC-QCL) has been developed using a modified Littrow-type cavity configuration. Scan rates up to 5 kHz and tuning ranges up to 7 cm−1 have been realized using folded cavity arrangement with a fast piezoactuated intracavity mirror to vary the effective diffraction grating angle. High-resolution molecular spectroscopy, limited primarily by the effective laser linewidth, has been demonstrated in pulsed and CW mode using direct absorption spectroscopy of ammonia and ethylene in the 10-μm wavelength region. A high-resolution broadband spectral scan employing mode-hop-free tuning of a set of discrete laser modes within the fast frequency scan has been developed. The method has been demonstrated by performing high-resolution broadband spectrum of ethylene under atmospheric and reduced pressures.

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Department of Electrical EngineeringPrinceton UniversityPrincetonUSA