Recently an all-optical Quasi Phase Matching (QPM) scheme for High Harmonic Generation (HHG) was introduced in which the pump beam was constructed in the form of an intensity grating whose periodicity could be easily tuned. This was performed using a two-component fundamental beam, superposing a Bessel beam and a Gaussian beam.
Here we present, theoretically and experimentally, a phase matched non-collinear Second Harmonic Generation (SHG) in a doped LiNbO3, using a similar easily tunable scheme.
The phase matching condition depends on both the spatial properties of the fundamental beam and the thermal properties of the medium. We show that a thermally induced phase-mismatch can be compensated by choosing the spatial properties of the pump beam controlled by the SLM, resulting in a phase-matched non-collinear SHG.
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