Enhanced intrapulse difference frequency generation in the mid-infrared by a spectrally dependent polarization state

Abstract : We present a technique to optimize the intrapulse difference frequency generation efficiency for mid-IR generation. The approach employs a multi-order waveplate that is designed to selectively rotate the polarization state of the incoming spectral components on the relevant orthogonal axes for subsequent nonlinear interaction. We demonstrate a significant increase of the mid-IR average power generated by a factor ≥ 2.5 compared to the conventional scheme, due to an optimally distributed number of photons enrolled in the difference frequency generation process.