Nonlinear waveguide grating couple

The use of a grating to facilitate the out-coupling has been demonstrated [52]. In that work, a (methyl-3 -(p-nitro-phenyl)carbazate, MNCZ) crystal was used as the substrate with a slab transparent waveguide made of photoresist deposited on top. The grating coupler was fabricated holographically and the SHG of a Nd YAG 1.06 pm laser demonstrated. This nonlinear crystal has a nonlinear d36 coefficient of 22.7 pm V-1 (3 time larger than d24 of KTP) and a cut-off wavelength of 455 nm. Reported conversion efficiencies were at that time limited by lack of sufficient crystal flatness. 

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