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Title: Measurement of electron beam polarization from unstrained GaAs via two-photon photoemission

Two-photon absorption of 1560 nm light was used to generate polarized electron beams from unstrained GaAs photocathodes of varying thickness: 625 {mu}m, 0.32 {mu}m, and 0.18 {mu}m. For each photocathode, the degree of spin polarization of the photoemitted beam was less than 50%, contradicting earlier predictions based on simple quantum mechanical selection rules for spherically-symmetric systems but consistent with the more sophisticated model of Bhat et al. (Phys. Rev. B 71 (2005) 035209). Polarization via two-photon absorption was the highest from the thinnest photocathode sample and comparable to that obtained via one-photon absorption (using 778 nm light), with values 40.3 +- 1.0% and 42.6 +- 1.0%, respectively.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [4]
  1. Univ. of Virginia, Charlottesville, VA (United States)
  2. George Washington Univ., Washingon, DC (United States)
  3. Univ. of Nebraska, Lincoln, NE (United States)
  4. JLAB, Newport News, VA (United States)
Publication Date:
OSTI Identifier:
1117624
Report Number(s):
JLAB-ACO--13-1749; DOE/OR--23177-2909
Journal ID: ISSN 0168-9002; TRN: US1400168
DOE Contract Number:
AC05-06OR23177
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; Journal Volume: 738
Publisher:
Elsevier
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC) (United States)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; POLARIZATION; PHOTOCATHODES; ELECTRON SOURCES Polarization; Two-photon; GaAs; Photocathode; Electron source