High energy cw-diode pumped Nd:YVO4 regenerative amplifier with efficient second harmonic generation.

We report on a 888 nm diode-pumped Nd:YVO4 regenerative amplifier with up to 33.7 W output power with a repetition-rate of 20 kHz and an adjustable pulse duration between 217 ps and 1 ns. This setup allowed for efficient second harmonic generation with an efficiency of up to 79%.

Efficient generation of mode-locked pulses in Nd:YVO4 with a pulse duration adjustable between 34 ps and 1 ns.

We report on the generation of highly stable active continuous mode-locked pulses in diode pumped Nd:YVO(4) with an adjustable pulse duration between 34 ps and 1 ns. With this laser an average output power of up to 7.3 W with an excellent stability and beam quality with a M(2)-value of < 1.

Wavelength tuning and spectral properties of distributed feedback diode lasers with a short external optical cavity.

We report on the wavelength tuning and spectral properties of distributed feedback (DFB) diode lasers operated with a plane external cavity (XC) mirror positioned as close as possible to the diode-laser front facet. These lasers generate single-frequency near IR radiation at wavelengths of 1392, 1580, 1602, and 1653 nm. A piezoelectric variation of the XC length provided continuous single-frequency tuning to as high as 19 GHz.

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.

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.

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%.

Single-frequency continuous-wave radiation from 0.77 to 1.73 microm generated by a green-pumped optical parametric oscillator with periodically poled LiTaO3.

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.

Continuous-wave quasi-phase-matched generation of 60 mW at 465 nm by single-pass frequency doubling of a laser diode in backswitch-poled lithium niobate.

We report continuous-wave single-pass second-harmonic generation (SHG) in 4-mum -period 0.5-mm-thick backswitch-poled lithium niobate. Pump sources at 920-930 nm include both Ti:sapphire and diode-oscillator-amplifier lasers.

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.

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 LiNbO(3) crystal in a four-mirror signal-resonant ring cavity. Pumped by 2.

1 W of blue 465-nm radiation generated by frequency doubling of the output of a high-power diode laser in critically phase-matched LiB3O5.

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) .

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

We report on optical parametric oscillators (OPO's) 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.

2.5-GHz repetition-rate singly resonant optical parametric oscillator synchronously pumped by a mode-locked diode oscillator amplifier system.

We report on an optical parametric oscillator (OPO) that is synchronously pumped directly by a diode laser. This laser is an actively mode-locked master-oscillator power-amplifier system that produces 20-ps pulses at 927 nm with a repetition rate of 2.5 GHz and an average power of 0.

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.

Origin of magnetic field enhancement in the generation of terahertz radiation from semiconductor surfaces.

We present a theory of the magnetic field enhancement of terahertz (THz) emission from photogenerated carriers in the surface depletion region of a semiconductor. A combination of the Drude-Lorentz model for the carrier dynamics with an appropriate solution of the radiation problem is sufficient to explain the strong B -field enhancement in THz radiation that has been observed experimentally. The effect arises primarily from the increased radiation efficiency of transient currents flowing in the plane of the surface.

Wide wavelength tuning of an optical parametric oscillator through electro-optic shaping of the gain spectrum.

We present a novel technique for tuning an optical parametric oscillator (OPO) through electro-optically induced shape variations of the parametric gain spectrum in quasi-phase-matched lithium niobate (LN). The diode-pumped, triply resonant continuous-wave OPO is based on a 58-mm-long LN crystal that consists of three equally long sections, the outer sections being periodically poled with a 50% duty cycle. The center section is single-domain material and serves as a tunable phase shifter through the electro-optic effect.

250 mW of coherent blue 460-nm light generated by single-pass frequency doubling of the output of a mode-locked high-power diode laser in periodically poled KTP.

We report on the generation of 250mW of coherent 460-nm light by single-pass frequency doubling of the mode-locked picosecond pulses emitted by an InGaAs diode master oscillator power amplifier in periodically poled KTP.

111 W, 110 MHz repetition-rate, passively mode-locked TEM00Nd:YVO4 master oscillator power amplifier pumped at 888 nm.

We report on an 888 nm pumped passively mode-locked TEM(00)Nd:YVO(4) oscillator providing 56 W of average power at a repetition rate of 110 MHz with 33 ps pulse duration, further amplified to 111 W in a 52% optical efficiency single-pass amplifier stage, maintaining beam quality at M(2)=1.05. Frequency doubling in a LiB(3)O(5) crystal generated up to 87 W at 532 nm, while a third harmonic power of 35 W was achieved in a nonoptimized tripling configuration, corresponding to 80% and 33% conversion efficiency.

Low-noise 62 W CW intracavity-doubled TEM00 Nd:YVO4 green laser pumped at 888 nm.

We present a CW intracavity frequency-doubled TEM(00) Nd:YVO(4) laser oscillator pumped at 888 nm, producing 62W of green light at 532 nm with M(2)=1.05 and RMS noise of 0.05%, thanks to the simultaneous oscillation of a large number of longitudinal modes.

47 W, 6 ns constant pulse duration, high-repetition-rate cavity-dumped Q-switched TEM(00) Nd:YVO(4) oscillator.

We report on a cavity-dumped Q-switched TEM(00) Nd:YVO(4) oscillator offering a unique combination of high power, constant short pulse duration, and high repetition rate, suppressing the gain dependence of pulse duration in classical Q-switched oscillators. Its performance is compared with that of the same oscillator operated in a classical Q-switched regime, demonstrating the much higher peak powers achievable with this technique, especially at high repetition rates. Up to 31 W of 532 nm green light was generated by frequency doubling in a noncritical phase matched LBO crystal, corresponding to 70% conversion efficiency.

High-efficiency 60 W TEM(00) Nd:YVO(4) oscillator pumped at 888 nm.

We propose a technique for pumping Nd:YVO(4) with high optical power at 888nm while making absorption independent of the pump light polarization state. This is especially suitable for systems end pumped by high-power, high-brightness fiber-coupled diode sources associated with long vanadate crystals to effectively spread the heat load in a large volume. A compact 60 W output, 55% optical efficiency cw TEM(00) oscillator was demonstrated.

Characterization and laser performance of a new material: 2 at. % Nd:YAG grown by the Czochralski method.

We report on the optical quality and laser performance of Czochralski-grown 2-at. %-doped Nd:YAG. Using a diode pumped laser in an end pumped configuration, we compare the laser performance of this material with the performance of 1-at.

Tuning characteristics of narrowband THz radiation generated via optical rectification in periodically poled lithium niobate.

The tuning properties of pulsed narrowband THz radiation generated via optical rectification in periodically poled lithium niobate have been investigated. Using a disk-shaped periodically poled crystal tuning was easily accomplished by rotating the crystal around its axis and observing the generated THz radiation in forward direction. In this way no beam deflection during tuning was observed.

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.

Single-mode continuous-wave Cr(3+):LiSAF ring laser pumped by an injection-locked 670-nm broad-area diode laser.

We report on an efficient continuous-wave Cr(3+):LiSrAlF(6) ring laser pumped by the near-diffraction-limited output of an injection-locked 665-nm broad-area diode laser. With an absorbed pump power of 120 mW the ring laser generates 22 mW of single-mode 855-nm radiation with a spectral linewidth of less than 10 MHz. Unidirectional operation and longitudinal-mode control of this ring laser is achieved by injection of 855-nm diode-laser radiation into the ring cavity.