R. Wallenstein

Diode-pumped singly resonant continuous-wave optical parametric oscillator with wide continuous tuning of the near-infrared idler wave.

We demonstrate wide, continuous tuning of the single-frequency idler wave of a cw singly resonant optical parametric oscillator (SRO). The SRO consists of a periodically poled LiNbO(3) crystal for quasi-phase matching in a four-mirror signal-resonant ring cavity. The SRO, excited by 2.25 W of 924-nm radiation from an InGaAs diode laser, generates as much as 200 mW of single-frequency 2.1-mum idler radiation. We tune the idler frequency continuously within a range as large as 56 GHz by changing the wavelength of the diode pump laser. The versatility of this continuously tunable single-frequency infrared source is demonstrated by recording of N(2)O rovibrational absorption lines near 2.1 mum.

Single-frequency continuous-wave optical parametric oscillator system with an ultrawide tuning range of 550 to 2830 nm

We present a cw single-frequency laser source with what is to our knowledge the largest emission range ever demonstrated, from the green to the mid-IR range. It employs a cw optical parametric oscillator with subsequent resonant frequency doubling. Typical output powers are 30–500 mW, with 160 mW at 580 nm. Mode-hop-free oscillation, high absolute frequency stability, 20-kHz-signal linewidth, and up to 38-GHz continuous tuning are demonstrated. Both PPLN and PPKTP are used as nonlinear materials, and their performance is compared.

Singly resonant continuous-wave optical parametric oscillator pumped by a diode laser

We report on what is believed to be the first singly resonant cw optical parametric oscillator (SRO) that is directly pumped by a diode laser. The SRO consists of a 38-mm-long periodically poled LiNbO3 crystal in a four-mirror signal-resonant ring cavity. Pumped by 2.5 W of 925-nm diode-laser radiation, the SRO generates 480 mW of single-frequency idler radiation at 2.1 µm. The wavelengths of the signal and the idler output are tuned in the ranges of 1.55 to 1.70 µm and 2.03 to 2.29 µm, respectively, by tuning the wavelength of the diode laser from 924.0 to 925.4 nm.

Periodically poled potassium niobate for second-harmonic generation at 463 nm.

We report on the fabrication and characterization of quasi-phase-matched potassium niobate crystals for second-harmonic generation. Periodic 30-mum -pitch antiparallel ferroelectric domains are fabricated by means of poling in an electrical field. Both birefrigence and periodic phase shift of the generated second harmonic contribute to phase matching when the d(31) nonlinear optical tensor element is used. 3.8 mW of second-harmonic radiation at 463 nm is generated by frequency doubling of the output of master-oscillator power-amplifier diode laser in a 5-mm-long crystal. The measured effective nonlinear coefficient is 3.7pm/V. The measured spectral acceptance bandwidth of 0.25 nm corresponds to the theoretical value.

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.

1??W of blue 465-nm radiation generated by frequency doubling of the output of a high-power diode laser in critically phase-matched LiB 3 O 5

Blue 465-nm radiation is generated by frequency doubling of the output of an InGaAs diode-laser oscillator-amplifier system in critically phase-matched LiB(3)O(5) (LBO). The diode-laser system emitted 4 W of single-frequency 930-nm radiation in a near-diffraction-limited beam (M(2)<1.2) . The laser power is enhanced to values of up to 150 W in a resonant external ring cavity. The LBO crystal is placed at a resonator internal focus. The frequency doubling in the LBO crystal generates blue radiation at 465 nm with a power of 1 W. The spectral width of the blue radiation is less than 3 MHz, and the value of the M(2) beam parameter is less than 1.2.

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.

Diode-pumped continuous-wave widely tunable optical parametric oscillator based on periodically poled lithium tantalate.

We report on a diode-laser pumped cw optical parametric oscillator (OPO) based on quasi-phase-matched periodically poled lithium tantalate. Pumped by the 2.3-W single-frequency, nearly diffraction-limited 925-nm output of an InGaAs diode master-oscillator power amplifier, the pump and signal resonant OPO generates a single-frequency idler wave with an output of as much as 244 mW. The wavelengths of the signal and idler waves are widely tunable in the range 1.55-2.3mum by use of different poling periods (27.3 to 27.9mum) and by variation of the crystal temperature in the range 70-190 degrees C.

Diode-pumped passively Q-switched self-frequency-doubling Nd:YAB laser

We report on a diode-pumped 531-nm self-frequency-doubling Nd:YAB laser passively Q switched by a Cr4+:YAG saturable absorber. Pumped by 1.4 W of 807-nm GaAlAs diode laser radiation, the Nd:YAB laser system generates 5.6-ns-long TEM00 light pulses with an energy of 1.0 µJ at a repetition rate of 45 kHz. The experimental data are compared with the results of a numerical analysis based on rate equations that consider the optical properties of the Nd:YAB crystal and of the Cr4+:YAG saturable absorber.

Single-frequency continuous-wave radiation from 0.77 to 1.73 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.