ABSTRACT
Spectral compression of Second-Harmonic Generation (SHG) is crucial for selective two-photon microscopy and high-precision nonlinear spectroscopy. In this paper, we report a experimental realization of second-harmonic spectral compression by Fresnel-inspired binary phase shaping for a Gaussian and transformed-limited Fundamental Pulse (FP). Given the FP bandwidth, a narrower SHG bandwidth can be obtained by simply increasing the number of binary phases. The best compression factor achieved in our experiments was 11.3, with a bandwidth (FWHM) of only 0.161 nm and high efficiency of 56%. These results will significantly facilitate the applications of selective two-photon microscopy and spectroscopy.
