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Optical parametric light generation is a unique way to obtain continuously tunable laser radiation in a wide spectral region. Relatively inexpensive and compact subnanosecond (100 ps - 1 ns) optical parametric generators (OPG) with broad wavelength tunability are needed for a variety of applications that do not require the high temporal resolution supplied by expensive and sophisticated ultrashort (<10 ps) laser systems, but nanosecond (>1 ns) time resolution is not sufficient. Such applications are spectroscopy, laser-induced fluorescence, detection of chemical materials, nonlinear microscopy, biochemical research and differential absorption lidar to name a few. Development and the reduced cost of the passively Q-switched micro-laser manufacturing technologies permits them to be used as a high energy pump source for subnanosecond OPGs. Such micro-laser pumped subnanosecond OPGs would allow the implementation of low-cost, compact, continuously tunable laser radiation sources suitable for the aforementioned applications, especially in near-infrared (NIR) and visible (VIS) spectral ranges where the demand is high. To date, no subnanosecond OPGs based on short (up to 2 cm in length) periodically poled (PP) crystals have been demonstrated that could also be continuously tunable over a wide spectral range. Long PP crystals are more expensive, therefore implementation and investigation of such OPGs would be commercially attractive. Here we investigate parametric light generator based on short (up to 2 cm in length) periodically poled lithium niobate (PPLN) crystal pumped by 473 ps pulses from a 1 mJ energy micro-laser. Experimentally measured spatial, temporal and energy characteristics of the generated light from different length PPLN crystals are shown and supplemented by numerical simulations of parametric generation in a nonlinear dispersive medium.
This work has received funding from European Regional Development Fund (project No. 01.2.2-LMT-K-718-03-0004) under grant agreement with the Research Council of Lithuania (LMTLT).
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