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Title: Femtosecond measurements of near-infrared pulse induced mid-infrared transmission modulation of quantum cascade lasers

We temporally resolved the ultrafast mid-infrared transmission modulation of quantum cascade lasers (QCLs) using a near-infrared pump/mid-infrared probe technique at room temperature. Two different femtosecond wavelength pumps were used with photon energy above and below the quantum well (QW) bandgap. The shorter wavelength pump modulates the mid-infrared probe transmission through interband transition assisted mechanisms, resulting in a high transmission modulation depth and several nanoseconds recovery lifetime. In contrast, pumping with a photon energy below the QW bandgap induces a smaller transmission modulation depth but much faster (several picoseconds) recovery lifetime, attributed to intersubband transition assisted mechanisms. The latter ultrafast modulation (>60 GHz) could provide a potential way to realize fast QCL based free space optical communication.
Authors:
;  [1] ;  [2] ;  [3] ; ; ;  [3] ;  [4] ;  [5] ;  [1] ;  [2] ;  [4]
  1. Department of Physics, University of Maryland, Baltimore County (UMBC), Baltimore, Maryland 21250 (United States)
  2. (CASPR), UMBC, Baltimore, Maryland 21250 (United States)
  3. Center for Advanced Studied in Photonics Research (CASPR), UMBC, Baltimore, Maryland 21250 (United States)
  4. (United States)
  5. AdTech Optics, Inc., City of Industry, California 91748 (United States)
Publication Date:
OSTI Identifier:
22300164
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 21; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ENERGY-LEVEL TRANSITIONS; GHZ RANGE; LASER RADIATION; LIFETIME; MODULATION; OPTICAL PUMPING; PHOTONS; QUANTUM WELLS; TEMPERATURE RANGE 0273-0400 K; TRANSMISSION; WAVELENGTHS