skip to main content

Title: Narrow-band injection seeding of a terahertz frequency quantum cascade laser: Selection and suppression of longitudinal modes

A periodically poled lithium niobate (PPLN) crystal with multiple poling periods is used to generate tunable narrow-bandwidth THz pulses for injection seeding a quantum cascade laser (QCL). We demonstrate that longitudinal modes of the quantum cascade laser close to the gain maximum can be selected or suppressed according to the seed spectrum. The QCL emission spectra obtained by electro-optic sampling from the quantum cascade laser, in the most favorable case, shows high selectivity and amplification of the longitudinal modes that overlap the frequency of the narrow-band seed. Proper selection of the narrow-band THz seed from the PPLN crystal discretely tunes the longitudinal mode emission of the quantum cascade laser. Moreover, the THz wave build-up within the laser cavity is studied as a function of the round-trip time. When the seed frequency is outside the maximum of the gain spectrum the laser emission shifts to the preferential longitudinal mode.
Authors:
; ; ;  [1] ;  [1] ;  [2] ; ; ; ; ;  [3] ;  [4]
  1. Arbeitsgruppe Terahertz Spektroskopie und Technologie, Ruhr-Universität Bochum, Bochum 44780 (Germany)
  2. (Germany)
  3. School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)
  4. Lehrstuhl für Angewandte Festkörperphysik, Ruhr-Universität Bochum, Bochum 44780 (Germany)
Publication Date:
OSTI Identifier:
22303490
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CRYSTALS; EMISSION; EMISSION SPECTRA; GAIN; INJECTION; LASER CAVITIES; LASERS; LITHIUM COMPOUNDS; NIOBATES; PERIODICITY; PULSES; THZ RANGE