Green-pumped Optical Parametric Oscillator Research Articles

Tunable femtosecond optical parametric oscillators resonating at 0.65-1.02 µm and 1.07-2.3 µm.

We present a singly resonant femtosecond optical parametric oscillator (OPO) cavity architecture supporting ultra-broadband wavelength tuning and efficient outcoupling of the generated optical pulses. Experimentally, we demonstrate an OPO with its oscillating wavelength tuned over 652-1017 nm and 1075-2289 nm, spanning nearly 1.8 octaves. This is, as far as we know, the widest resonant-wave tuning range obtained from a green-pumped OPO. We show that intracavity dispersion management is crucial for the stationary and single-band operation of such a broadband wavelength tuning system. This architecture is universal, and therefore can be extended to allow the oscillation and ultra-broadband tuning of OPOs at various spectral regions.

Watt-level, green-pumped optical parametric oscillator based on periodically poled potassium titanyl phosphate with high extraction efficiency

We report a compact, efficient optical parametric oscillator (OPO) based on a periodically poled potassium titanyl phosphate (PPKTP) crystal pumped by a 532 nm laser, which generated 1.51 W of average power at the signal wavelength of 709 nm with the pulse duration of ∼ 1.0 ns. The extraction efficiency was up to 59%. To the best of our knowledge, this is the first report on Watt-level green-pumped PPKTP-based singly resonant oscillator OPO (SRO-OPO). The precise build-up time of OPO was determined to be 1.6 ns benefitting from the characteristic of twin-peak pulse profile of pump beam. The spectrum width of the idler was also measured to be 4.2 nm with the central wavelength of 2134 nm at 0.2 nm spectral resolution of optical spectrum analyzer. In addition, the beam quality of M 2 < 1.9 of generated signal exhibits a good consistency with M 2 < 1.5 for the pump source.

Green-pumped optical parametric oscillator based on fan-out grating periodically-poled MgO-doped congruent LiTaO3.

We report a green-pumped optical parametric oscillator (OPO) based on periodically poled MgO-doped congruent lithium tantalate (MgO:cPPLT). Pumped at 532nm by a frequency-doubled Q-switched Nd:YAG laser, and using a fan-out grating structure, the singly-resonant OPO provides continuous tuning across 689-1025nm in the signal and 1106-2336nm in the idler at room temperature by simple mechanical translation of the crystal. The tuning range can be further extended to 677nm and 2479nm in the signal and idler, respectively, by temperature tuning the crystal to 200°C. With a 29-mm-long crystal, the OPO generates 131mW of average idler power at 1476.5nm for an input pump power of 1.8W at 25kHz repetition rate, with a slope efficiency of 11.3%. Bulk damage in the MgO:cPPLT crystal has been observed for pump powers above ∼1.8 W, and at pump powers beyond ∼1.4 W under long-term operation. The passive power stability of the generated idler is 3.9% over 30min, in a Gaussian spatial profile.

Femtosecond OPO based on LBO pumped by a frequency-doubled Yb-fiber laser-amplifier system for CARS spectroscopy

We present detailed investigations of a femtosecond green-pumped optical parametric oscillator (OPO) based on lithium triborate. As pump source, a frequency-doubled Yb-fiber laser-amplifier system is used. The OPO generates signal pulses tunable over a spectral range from 780 to 940 nm and idler pulses tunable from 1630 to 1190 nm. More than 250 mW are generated in the signal beam and more than 300 mW in the idler beam. Without dispersion compensation chirped signal pulses with a pulse duration between 100 and 250 fs are measured. Using this system for coherent anti-Stokes Raman scattering spectroscopy, vibrational resonances between 1110 and 6760 cm−1 can be excited. Due to the chirped pulses, a spectral resolution of 100 cm−1 is achieved, which is 2.5 times higher compared to an excitation with time-bandwidth limited pulses.

Single-frequency continuous-wave radiation from 077 to 173 µm generated by a green-pumped optical parametric oscillator with periodically poled LiTaO_3

We describe a cw optical parametric oscillator (OPO) with multigrating periodically poled LiTaO(3) . Pumped by a single-frequency 532-nm laser, the OPO emits single-frequency radiation at wavelengths from 0.77 to 1.73 microm with as much as 60 mW of output power. Mode-hop-free operation for as long as 50 min, a low frequency drift (<70 MHz/h), and as much as 700-MHz continuous frequency tuning of signal and idler are demonstrated.