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Title: Direct measurements of multi-photon induced nonlinear lattice dynamics in semiconductors via time-resolved x-ray scattering

Nonlinear optical phenomena in semiconductors present several fundamental problems in modern optics that are of great importance for the development of optoelectronic devices. In particular, the details of photo-induced lattice dynamics at early time-scales prior to carrier recombination remain poorly understood. We demonstrate the first integrated measurements of both optical and structural, material-dependent quantities while also inferring the bulk impulsive strain profile by using high spatial-resolution time-resolved x-ray scattering (TRXS) on bulk crystalline gallium arsenide. Our findings reveal distinctive laser-fluence dependent crystal lattice responses, which are not described by previous TRXS experiments or models. The initial linear expansion of the crystal upon laser excitation stagnates at a laser fluence corresponding to the saturation of the free carrier density before resuming expansion in a third regime at higher fluences where two-photon absorption becomes dominant. Our interpretations of the lattice dynamics as nonlinear optical effects are confirmed by numerical simulations and by additional measurements in an n-type semiconductor that allows higher-order nonlinear optical processes to be directly observed as modulations of x-ray diffraction lineshapes.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [4]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); DePaul Univ., Chicago, IL (United States)
  2. Korea Research Inst. of Standards and Science (KRISS), Daejeon (Korea, Republic of); Univ. of Science and Technology (UST), Daejeon (Korea, Republic of)
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
  4. DePaul Univ., Chicago, IL (United States)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Soong-Sil Univ, Seoul (Korea, Republic of)
  6. Soong-Sil Univ, Seoul (Korea, Republic of)
Publication Date:
Report Number(s):
LLNL-JRNL-731799
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC52-07NA27344; AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 6; Journal Issue: 1; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Research Foundation of Korea (NRF); Research Corporation for Science Advancement
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; Applied physics; Semiconductors; X-rays
OSTI Identifier:
1361613
Alternate Identifier(s):
OSTI ID: 1417997