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Title: Anisotropy of two-photon absorption and free-carrier effect in nonpolar GaN

We reported a systematic study about the anisotropic optical nonlinearities in bulk m-plane and a-plane GaN crystals by Z-scan and pump-probe with phase object methods under picosecond at 532 nm. The two-photon absorption coefficient, which was measured as a function of polarization angle, exhibited oscillation curves with a period of π/2, indicating a highly polarized optical third-order nonlinearity in both nonpolar GaN samples. Furthermore, free-carrier absorption revealed stronger hole-related absorption for E⊥c than for E//c probe polarization. In contrast, free-carrier refraction was found almost isotropic due to electron-related refraction in the isotropic conduction bands.
Authors:
; ;  [1] ; ; ;  [2] ;  [1] ;  [3]
  1. College of Physics, Optoelectronics and Energy, Soochow University, 215006 Suzhou (China)
  2. Department of Physics, Harbin Institute of Technology, 150001 Harbin (China)
  3. (China)
Publication Date:
OSTI Identifier:
22398809
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 13; Other Information: (c) 2015 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; ABSORPTION; ANGULAR DISTRIBUTION; ANISOTROPY; CHARGE CARRIERS; CRYSTALS; DIAGRAMS; ELECTRONIC STRUCTURE; ELECTRONS; GALLIUM NITRIDES; HOLES; NONLINEAR PROBLEMS; OSCILLATIONS; PHOTONS; POLARIZATION; PROBES; REFRACTION