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Title: Imaging of free carriers in semiconductors via optical feedback in terahertz quantum cascade lasers

To monitor the density of photo-generated charge carriers on a semiconductor surface, we demonstrate a detectorless imaging system based on the analysis of the optical feedback in terahertz quantum cascade lasers. Photo-excited free electron carriers are created in high resistivity n-type silicon wafers via low power (≅40 mW/cm{sup 2}) continuous wave pump laser in the near infrared spectral range. A spatial light modulator allows to directly reconfigure and control the photo-patterned intensity and the associated free-carrier density distribution. The experimental results are in good agreement with the numerical simulations.
Authors:
; ; ;  [1] ;  [2] ;  [1] ;  [2] ;  [2] ;  [3]
  1. Dipartimento Interateneo di Fisica, Università degli Studi e Politecnico di Bari, via Amendola 173, 70126 Bari (Italy)
  2. (Italy)
  3. NEST, CNR - Istituto Nanoscienze and Scuola Normale Superiore, piazza San Silvestro 12, 56127 Pisa (Italy)
Publication Date:
OSTI Identifier:
22280713
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 4; 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; CARRIER DENSITY; CHARGE CARRIERS; COMPUTERIZED SIMULATION; ELECTRIC CONDUCTIVITY; ELECTRONS; FEEDBACK; N-TYPE CONDUCTORS; SILICON; SOLID STATE LASERS; SURFACES; THZ RANGE; VISIBLE RADIATION