A. Borsutzky

Pulsed nanosecond optical parametric generator based on periodically poled lithium niobate

Abstract In this paper we report on a pulsed nanosecond optical parametric generator (OPG) of congruent periodically poled lithium niobate (PPLN). The OPG is excited by TEM 00 single frequency pulses (duration: 10 ns, repetition rate: 10 kHz) of a Q-switched Nd:YVO 4 laser system. With 7.2 W of average power the OPG generated 1.6 W of signal and 0.76 W of idler radiation. The signal and idler waves are tunable in the range of 1.56–1.64 and 3.34–3.03 μm, respectively, by changing the temperature of the PPLN crystal. Injection seeding with 3 mW of cw 1.580 μm light of a tunable DFB diode laser narrowed the spectral width of the OPG signal wave to less than 140 MHz.

Nanosecond periodically poled lithium niobate optical parametric generator pumped at 532 nm by a single-frequency passively Q-switched Nd:YAG laser.

We report an efficient, visible, nanosecond optical parametric generator of periodically poled lithium niobate pumped at 532 nm by a frequency-doubled, diode-pumped, passively Q -switched, single-mode Nd:YAG laser with 90-muJ pulse energy. The signal radiation is tunable from 637 to 593 nm. The maximum signal-conversion efficiency is 23%. Optical parametric amplification of a He-Ne laser at 632.8 nm is also studied.

Nanosecond optical parametric oscillator based on large-aperture periodically poled RbTiOAsO 4

We report on optical parametric oscillators (OPOs) based on periodically poled RbTiOAsO(4) (PP RTA), which are pumped by Q -switched solid-state lasers. With a diode-pumped Nd:YVO(4) laser (pulse energy, 800microJ ; pulse duration, 5.5 ns; repetition rate, 1 kHz) the PP RTA OPO generated 1.58-microm signal and 3.26-microm idler radiation with a signal pulse energy of 45microJ . The large aperture of 3 mmx3 mm of the PP RTA crystal also permitted OPO operation with pump pulse energies as high as 65 mJ, provided by a flash-lamp-pumped Q -switched Nd:YAG laser (pulse duration, 20 ns; repetition rate, 10 Hz). With this pump source the OPO generated signal pulse energies as high as 17 mJ, corresponding to an efficiency of 26%. The performance of this OPO shows that large-aperture PP RTA crystals are well suited for pulsed nanosecond OPO operation with pump pulse energies of tens of millijoules.

Optical parametric oscillator of quasi-phasematched LiNbO3 pumped by a compact high repetition rate single-frequency passively Q-switched Nd:YAG laser

Abstract We report on an efficient diode pumped compact source of pulsed tunable infrared radiation based on a high repetition rate single frequency passively Q -switched Nd:YAG laser and an optical parametric oscillator (OPO) of quasi-phase matched LiNbO 3 . When pumped by 5.4 W of 810 nm cw diode laser radiation the Nd:YAG laser (which is passively Q -switched by a Cr 4+ :GSGG saturable absorber) oscillates on a single-longitudinal mode and emits in a diffraction limited beam light pulses with duration of 2 ns, pulse energy of 100 μJ, repetition rate of 1.1 kHz and average power of 110 mW. This radiation excites an OPO of quasi-phase matched LiNbO 3 . The OPO generates signal and idler radiation which is tunable in the range of 1.46–1.61 μm and 3.13–3.92 μm, respectively. Tuning is achieved by using 8 different poling periods ( Λ =28.5–29.9 μm) and by changing the crystals temperature in the range of 80–160°C. The measured signal pulse energy is E S =22 μJ, the average signal output power P S =24 mW, the measured idler power P I =2.5 mW and the pump depletion 33%.

Spectral properties and conversion efficiency of 355-nm-pumped pulsed optical parametric oscillators of β-barium borate with noncollinear phase matching

We report on a theoretical and experimental investigation of the spectral properties and the conversion efficiency of 355-nm-pumped pulsed optical parametric oscillators (OPO’s) of β-barium borate with noncollinear phase matching. If the noncollinear phase matching is tangential, the pump wave’s angular acceptance—which is approximately 0.3 mrad cm-1 for collinear excitation—is increased as much as 9 mrad cm-1. Because of the large angular acceptance the OPO output energy increases to a factor of 4 greater than that for conventional collinear excitation when the OPO is pumped by a laser beam with a divergence of 3 mrad. Besides an increase in efficiency, the noncollinear phase matching provides a broadening of the spectral width of the OPO signal radiation of as much as 20 nm in the whole tuning range of 420–700 nm. The measured spectral widths are in good agreement with the results of an analysis that takes into account the influence of the divergence of the resonant OPO wave.

Large-aperture optical parametric oscillator with periodically poled KTiOPO/sub 4/

Summary form only given. Periodically poled ferroelectric crystals have been extensively used in nonlinear optical devices such as frequency doublers and optical parametric oscillators (OPOs) due to the large effective nonlinear coefficients, d/sub eff/, accessible through quasi-phase-matching and the possibility to engineer them for noncritical interaction. Primarily, the small apertures of available periodically poled crystals have imposed a limitation of the pulse energy that can be extracted using nanosecond pulses. In this work we report on the power scaling above 10 mJ in a singly resonant OPO realized with a 3-mm-thick periodically poled KTiOPO/sub 4/. We made a comparison of the OPO performance with several low repetition rate pump systems. The crystal behaves similarly for all these flash-lamp pump systems. The observed differences in saturated efficiency could be attributed to different intensity distributions of the pump beam. We also present results of the tuning of the signal and idler with temperature. An experimental investigation of the spatial qualities of the high-power parametric output, in the form of the M/sup 2/-value, is also given.

High-power nanosecond optical parametric oscillator at 1.6 /spl mu/m based on periodically poled RbTiOAsO/sub 4/

We have demonstrated the suitability of periodically poled RbTiOAsO/sub 4/ (RTA) in high pulse-energy optical parametric oscillators (OPOs). The 3-mm-thick RTA crystal is to our best knowledge the thickest ferroelectric crystal that has been periodically poled so far.