Browsing by Subject "Frequency conversion"
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Item Open Access Highly efficient wavelength conversion of Q-switched Nd: YAG lasers into a red wavelength(Institute of Electrical and Electronics Engineers, 2006) Figen, Z. G.; Yalabik, A.; Aytür, O.We report a nanosecond upconversion optical parametric oscillator which can convert the output of a Nd:YAG laser at 1064-nm wavelength into 627 nm with high efficiency. This device is based on a single KTiOAsO4 crystal that is simultaneously phase matched for optical parametric generation and sum-frequency generation. Pumped at a wavelength of 1064 nm by a Q-switched Nd:YAG laser in a double-pass configuration, this device produces 14.2-ns-long 5.8-mJ red pulses at a wavelength of 627 nm with 29% energy conversion efficiency. In addition, we developed a theoretical model for this device, whose predictions agree reasonably well with our experimental results. It is possible to scale this device for use with higher energy pump lasers and to shape it into a physically small semi-monolithic configuration.Item Open Access Multimode pumping of optical parametric oscillators(Institute of Electrical and Electronics Engineers, 1996-02) Marshall, L. R.; Kaz, A.; Aytur, O.Calculations suggest that optical parametric oscillators (OPO's) can be efficiently pumped using multimode, divergent pump sources. The influence of pump beam divergence and mode structure upon OPO performance is measured for both noncritical phase-matching, and OPO's with walkoff. Multimode OPO pumping is shown to be efficient, provided appropriate nonlinear crystals and OPO cavities are employed; the nonlinear crystal must have sufficient angular acceptance to tolerate a divergent pump; the OPO cavity must support modes that match the divergence and spatial intensity characteristics of the pump, For low-order pump modes, the OPO can be made to match the mode of the pump. Higher order pump modes reduce the OPO efficiency, and cause a saturation of efficiency with increasing pump power. The efficiency is degraded in a similar fashion in the presence of walkoff. Multimode pumping is more difficult in longer OPO cavities due to increased buildup time of higher order OPO modes.Item Open Access Nanosecond sum-frequency generating optical parametric oscillator using simultaneous phase matching(Optical Society of American (OSA), 2005) Figen, Z.G.; Aytür O.We report a nanosecond sum-frequency generating optical parametric oscillator based on a single KTiOAsO4 crystal that is simultaneously phase matched for optical parametric generation and sum-frequency generation. Pumped at a wavelength of 1064 nm by a Q-switched Nd:YAG laser, this device produces 10.4-ns-long 8.3 mJ red pulses at a wavelength of 627 nm with 21% energy conversion efficiency. This device provides a simple and efficient method for converting high energy Nd:YAG lasers to a red wavelength. © 2005 Optical Society of America.