Second harmonic generation (SHG) from resonant GaAs gratings

Author/Creator ORCID

Date

2011-05-22

Department

Program

Citation of Original Publication

de Ceglia, D.; et al.; Second harmonic generation (SHG) from resonant GaAs gratings; CLEO/Europe and EQEC 2011 Conference Digest OSA Technical Digest (CD) (Optical Society of America, 2011), paper EF2_5; https://www.osapublishing.org/abstract.cfm?uri=EQEC-2011-EF2_5

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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.

Subjects

Abstract

We study SHG in nonlinear (NL), GaAs gratings. We find large enhancement of conversion efficiency when the pump field excites the guided mode resonances (GMRs) [1] of the grating. Under these circumstances the spectrum near the pump wavelength displays sharp resonances characterized by dramatic enhancements of local fields and favorable conditions for second harmonic generation, even in regimes of strong linear absorption at the SH wavelength thanks to the phase-locked (PL) component of the SH [2]. In particular, in a GaAs grating pumped at 1064nm, we predict SH conversion efficiencies approximately five orders of magnitude larger than conversion rates achievable in either bulk or etalon structures of the same materials [3]. In Fig.1a) we sketch the geometry under consideration and in Fig.1b) we calculate the forward SH conversion efficiency ๐œ‚=๐‘ƒโ‚›โ‚•/๐‘ƒยฒ๐น๐น as function of the grating thickness W and compare it with the conversion efficiency of a bulk GaAs and with the conversion efficiency of an etalon GaAs placed in vacuo. The pump field incident at 100 on the grating is TE-polarized and the generated SH is also TE-polarized. This is a typical experimental configuration for SHG in GaAs [2].