K.-J. Boller

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.

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.

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.

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.

A 180 mW Nd:LaSc3(BO3)4 single-frequency TEM00 microchip laser pumped by an injection-locked diode-laser array

A TEM00 single-frequency, diode-pumped microchip laser of Nd(25%):LaSc3(BO3)4 is operated with an output power of 180 mW. For best performance the laser was pumped by the 450 mW diffraction-limited single-frequency radiation of an injection-locked AlGaAs diode-laser array and cooled to the temperature of liquid nitrogen. The active and passive losses of the microchip laser were investigated by measuring the relaxation oscillation frequency and by comparing the experimental results with values obtained from appropriate rate equations. The power-dependent far-field pattern is in good agreement with the intensity distribution calculated by assuming a thermally induced waveguide cavity.

Frequency-stable operation of a diode-pumped continuous-wave RbTiOAsO(4) optical parametric oscillator.

Frequency-stable operation of a diode-pumped continuous-wave optical parametric oscillator (OPO) of RbTiOAsO(4) is demonstrated. Piezoelectric and fast electro-optic control of the optical length of the two-mirror OPO cavity (resonant for the pump and the idler waves) compensates for thermal changes in the refractive index of the OPO crystal (induced by absorption of pump light) and acoustic perturbations of the cavity length. Pumped by 405mW of the 810-nm output of a GaAlAs masterf-oscillator-tapered-amplifier diode laser system, the OPO generates a power-stable single-frequency signal wave at 1.24microm with an output of 84mW and a spectral bandwidth of less than 10MHz.

Self-injection-locking of a CW-OPO by intracavity frequency-doubling the idler wave

We report on the observation of self-injection-locking of the signal wave of an optical parametric oscillator (OPO) with the intracavity frequency doubled idler wave. The two-mirror OPO is based on a periodically poled LiNbO3 (PPLN) crystal and pumped with a grating stabilized, continuous-wave (CW) single-frequency diode master-oscillator power-amplifier (MOPA) system. Simultaneous quasi-phase-matching (QPM) of OPO and second harmonic generation (SHG) is provided in the same crystal which carries two different domain gratings. The beat of the signal wave and the frequency-doubled idler wave is suppressed within a 500-kHz wide frequency range centered around zero as expected for self-injection- locking. The measurements prove the feasibility of optically phase-stabilized by-three-division of an optical frequency with CW-OPOs using cascaded nonlinearities.