A picosecond near-infrared laser source based on a self-seeded optical parametric generator

Abstract

We report on the design and development of a new type of near-IR laser source. The source comprises of an optical parametric generator (OPG) and a second harmonic generator (SHG) pumped by an 80-MHz, 1064-nm, 7-ps Nd:YVO4 laser. The OPG is self-seeded with a fraction of its own signal output, which significantly enhances its conversion efficiency. The SHG doubles the frequency of OPG signal to produce a coherent output. The final output beam has a tunable wavelength near 800 nm, an average power of over 1 W, and a pulse duration around 5 ps. The M2-factor of the output beam can reach 1.1 after spatial filtering. With the new laser source, we have successfully demonstrated coherent anti-Stokes Raman scattering microscopy on 1 μm polystyrene beads, which shows that it has the potential to be a substitute for a picosecond optical parametric oscillator in certain microscopy or spectroscopy applications.