All-solid-state Nd:YVO<Subscript>4</Subscript> laser at 1342 nm under 914 nm diode laser pumping

A Nd:YVO₄ crystal was pumped directly into the emitting level by a laser diode at 914 nm. We achieved an output power of 1.46 W at 1342 nm for an incident pump power of 18.3 W, corresponding to an optical-to-optical conversion efficiency of 8.0%. The fluctuation of the output power was better than 2.3% in the given 30 min. The beam quality M₂ factor value was equal to 1.15 at the maximum output power.     

Continuous wave,singly resonant MgO:PPLN OPO pumped by a Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> ring laser

A continuous wave (CW), extra-cavity singly resonant optical parametric oscillator (SRO) has been demonstrated. The SRO is based on 5% magnesium-oxide doped periodically-poled lithium niobate (MgO:PPLN) pumped by a CW Nd:YVO₄/YVO₄ ring laser centered at 1064.4 nm. The nonlinear crystal temperature is kept at 120.0 ± 0.1°C and a domain period of 30 μm is used in this experiment. When the pump power is 11 W, an output power of 2.0 W at the idler wavelength of 3.479 μm has been obtained from the OPO. The optical-optical conversion efficiency is about 18.2%, and the slope efficiency is about 20.8%.     

880 nm laser-diode end-pumped Nd:YVO<Subscript>4</Subscript> slab laser at 1342 nm

43.6 W near-diffraction-limited continuous-wave laser beam at 1342 nm in 880 nm laser-diode partially end-pumped Nd:YVO₄ slab laser is presented. The slope efficiency and optical-to-optical efficiency with respect to absorbed pumping power were 45.4% and 35.9%, respectively. At output power of 34.5 W, the M ² factors in unstable and stable directions were 1.3 and 1.2, respectively.     

Diode-pumped Nd:YVO<Subscript>4</Subscript>-LBO laser at 544 nm based on intracavity sum frequency generation

A dual-wavelength continuous-wave (CW) diode-pumped Nd:YVO₄ laser that generates simultaneous laser action at the wavelengths 914 and 1342 nm is demonstrated. A total dual-wavelength output power of 1.79 W was achieved at the incident pump power of 18.2 W. Furthermore, intracavity sum-frequency mixing at 914 and 1342 nm was then realized in a LBO crystal to reach the yellow-green range. We obtained a total CW output power of 212 mW at 544 nm.     

Passively Q-switched laser operation in a composite Nd:YVO<Subscript>4</Subscript>/Nd:YVO<Subscript>4</Subscript>/Nd:YVO<Subscript>4</Subscript> crystal with a single-walled carbon nanotube saturable absorber

By using a piece of single-walled carbon nanotube saturable absorber, the performance of the passively Q-switched composite Nd:YVO₄ laser has been demonstrated for the first time. The maximum average output power and the shortest pulse width are 1220 mW and 103 ns at the incident pump power of 5.04 W for a 10% transmission of the output coupler. The highest pulse repetition rate of 415.6 kHz and the largest single-pulse energy of 2.94 μJ are also obtained. The composite Nd:YVO₄ crystal has more excellent laser performance than the normal Nd:YVO₄ crystal at 1064 nm.     

Dual-wavelength oscillation at 1064 and 1342 nm in a passively Q-switched Nd:YVO<Subscript>4</Subscript> laser with V<Superscript>3+</Superscript>:YAG as saturable absorber

The efficient dual-wavelength oscillation at 1064 and 1342 nm in the passively Q-switched laser based on Nd:YVO₄/V³⁺:YAG is successfully obtained, as demonstrated in this paper. A total average output power of 2.2 W is obtained with 1.3 W for 1064 nm and 0.9 W for 1342 nm under the incident pump power of 7.7 W, corresponding to a total optical-optical conversion efficiency of 28.2%. The pulse widths are 58 and 54 ns for 1064 and 1342 nm, respectively, with the repetition rate of 89 kHz. Moreover, a rate equation model considering the Gaussian spatial distributions of the intracavity photon density and the initial population-inversion density is presented to characterize the dual-wavelength passive Q-switching operation.     

888 nm pumped 1342 nm Nd:YVO<Subscript>4</Subscript> oscillator Kerr-lens mode-locked using cascaded second-order nonlinearities

We report on a parametric Kerr-lens mode-locked 888 nm pumped Nd:YVO₄ 1342 nm oscillator using cascaded second-order nonlinearities in LBO. Stable ps-pulse-operation was achieved. For an output coupling of T=25% high average output power of 6.5 W, emitting Fourier-limited pulses with a duration of 10 ps was reached. By changing the output coupling to T=10%, we achieved much shorter pulses with a pulse duration of 4 ps for less lower average power of 4.8 W. The beam was diffraction limited with an M ² parameter better than <1.05.     

Single-longitudinal mode Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript>/KTP green solid state laser

We present the concept and practical realization of a single frequency, tuneable diode pumped Nd:YVO₄/YVO₄/KTP microchip laser operating at 532 nm. Theoretical analysis of the single mode operation of such a laser configuration is presented. The single frequency operation has been obtained in a birefringent filter, where an YVO₄ beam displacer acts as an ideal polarizer. Experimental results are in good agreement with theoretical analysis. We have obtained stable single frequency operation, tuneable over 0.6 nm in the spectral range around 1064 nm. The laser operated with output power up to 110 mW at 53 nm. The total optical efficiency (808 nm to 532 nm) was 14%.     

Diode-pumped Nd:LuVO<Subscript>4</Subscript>-Nd:YVO<Subscript>4</Subscript> laser at 492 nm with intracavity sum-frequency-mixing in LiB<Subscript>3</Subscript>O<Subscript>6</Subscript>

We present for the first time a Nd:YVO₄ laser emitting at 1064 nm intracavity pumped by a 916 nm diode-pumped Nd:LuVO₄ laser. A 809 nm laser diode is used to pump the Nd:LuVO₄ crystal emitting at 916 nm, a Nd:YVO₄ laser crystal was pumped at 916 nm and lased at 1064 nm. Intracavity sum-frequency mixing at 916 and 1064 nm was then realized in a LiB₃O₆ (LBO) crystal to reach the blue range. We obtained a continuous-wave output power of 216 mW at 492 nm under 19.6 W of incident pump power at 809 nm.     

Quasi-three-level Nd:YVO<Subscript>4</Subscript> laser operation at 914 nm under 879 nm diode laser pumping

We present experimental investigation on quasi-three-level Nd:YVO₄ laser operation at 914 nm under 879 nm diode pumping directly into emitting level. A maximal output power of 3.0 W under an absorbed pump power of 13.4 W was got, corresponding to an optical conversion efficiency of 22.4% and a slope efficiency of 40.3%. To the best of our knowledge, this is the first report on a Nd:YVO₄ laser at 914 nm using rod-type single crystal as the gain medium and end pumped by diode directly into the emitting level.     

Passively Q-switched yellow laser formed by a self-Raman composite Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> crystal

Passively Q-switched yellow output from a frequency-doubled self-stimulating Raman composite Nd:YVO₄/YVO₄ laser using a Cr:YAG saturable absorber is reported. Maximum yellow output power of 264 mW was obtained with corresponding diode to yellow conversion efficiency of 5.9%.     

High efficiency continuous-wave single-frequency Nd:YVO<Subscript>4</Subscript> ring laser under diode pumping at 880 nm

An efficient single-frequency continuous-wave Nd:YVO₄ ring laser pumped at 880 nm is presented. With compact four-mirror ring cavity and optical isolator, we obtained an output power of 14.56 W at 1064 nm, corresponding to a slope efficiency of 61.7% and an optical-to-optical efficiency of 58.4% with respect to the absorbed pump power. The stability of the output power was better than ±0.5% over two hours. At the same time, a beam quality factor of M ²≈1.2 was measured and the line width of the longitudinal mode was about 25 MHz. To the best of our knowledge, this is the highest slope efficiency and optical-to-optical efficiency in single-frequency Nd:YVO₄ ring laser.     

Continuous-wave passively mode-locked Nd:YVO<Subscript>4</Subscript>/KTP green laser with a semiconductor saturable absorber mirror

A diode-pumped passively mode-locked low-doped Nd:YVO₄ green laser with a semiconductor saturable absorber mirror (SESAM) and an intracavity frequency-doubling KTP crystal is demonstrated. In order to efficiently release the thermal effect, a low-doped Nd:YVO₄ crystal with the Nd³⁺ concentration of 0.1 at % is employed as the gain medium. The maximum average output power of 3.1 W at 532 nm with a repetition rate of 102 MHz is obtained under the pump power of 25 W, corresponding to an optical conversion efficiency of 12.4%. The 532 nm mode locked pulse width is estimated to be approximately 6.1 ps.     

Diode-pumped Nd:YVO<Subscript>4</Subscript>/Nd:YLF laser at 488 nm

We present a laser architecture to obtain continuous-wave blue radiation at 488 nm. A 808 nm diode-pumped the Nd:YVO₄ crystal emitting at 914 nm. A part of the pump power was then absorbed by the Nd:YVO₄ crystal. The remaining was used to pump the Nd:YLiF₄ (Nd:YLF) crystal emitting at 1047 nm. Intracavity sum-frequency mixing at 914 and 1047 nm was then realized in a BiB₃O₆ (BiBO) crystal to reach the blue radiation. We obtained a continuous-wave output power of 339 mW at 488 nm with a pump laser diode emitting 18.3 W at 808 nm.     

Diode-pumped Nd:YVO<Subscript>4</Subscript> intracavity-doubled red laser at 693 nm

It is reported that efficient continuous-wave (CW) red laser generation at 693 nm in a LBO crystal at type-I phase matching direction performed with a diode-pumped Nd:YVO₄ laser. With incident pump power of 18.2 W, output power of 278 mW at 693 nm has been obtained using a 10 mm-long LBO crystal. At the output power level of 278 mW, the output stability is better than 2.9%.     

High-pulse-stability double-end continuous-grown YVO<Subscript>4</Subscript>/Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> acousto-optically Q-switched laser at high repetition rates

High pulse amplitude stability of 0.62% (rms) is achieved at 60 kHz repetition rate in fundamental mode with double-end continuous-grown YVO₄/Nd:YVO₄/YVO₄ composite crystal. The average output power and pulse peak power are 32.9 W and 27.7 kW, respectively, with 19.8 ns pulse width and 548 μJ pulse energy. The pulse amplitude stability is investigated experimentally. The stability gets improved with the decrease of repetition rate and output transmission. From theoretical analysis, the reason of pulse instability at high repetition rates is that the initial population inversion doesn’t saturate and the final population inversion doesn’t approach zero. With the decrease of repetition rate and output transmission, the final population inversion decreases and the interaction between two adjacent pulse periods is weakened. Therefore, pulse stability improves.     

Dual-wavelength laser operation at 1064 and 914 nm in two Nd:YVO<Subscript>4</Subscript> crystals

We present for the first time a dual-wavelength laser operation at 1064 and 914 nm in two NdYVO₄ crystals. A 879 nm laser diode is used to pump the first Nd:YVO₄ crystal emitting at 914 nm, and the second Nd:YVO₄ laser emitting at 1064 nm intracavity pumped at 914 nm. A total output power of 4.28 W at the two fundamental wavelengths was achieved at the absorbed pump power of 13.8 W. The M² values for 914 and 1064 nm lights at the maximum output power were found to be around 1.3 and 1.1, respectively.     

Quasi-three-level Nd:YVO<Subscript>4</Subscript> laser by diode pumping at 888 nm

We report efficient laser emission on the 914 nm ⁴ F _3/2 to ⁴ I _9/2 transition in Nd:YVO₄ under the pump with diode lasers at 888 nm for the first time. Continuous wave 6.57 W output power at 914 nm is obtained from a V-type resonator under 18.3 W of absorbed pump power; the slope efficiency with respect to the absorbed pump power was 60.6%. Moreover, intracavity frequency doubling with BiB₃O₆ (BiBO) nonlinear crystal yielded 1.77 W of deep-blue light at 457 nm with beam quality characterized by an M₂ factor of 1.25.     

Nd:YVO₄ amplifier for ultrafast low-power lasers

An Nd:YVO₄ amplifier consisting of two modules end pumped at 808?nm at 30?W total absorbed power has been designed for efficient, diffraction-limited amplification of ultrafast pulses from low-power seeders. We investigated amplification with a 50?mW, 7?ps Nd:YVO₄ oscillator, a 2?mW, 15?ps Yb fiber laser, and a 30?mW, 300?fs Nd:glass laser. Output power as high as 9.5?W with 8?ps pulses was achieved with the 250?MHz vanadate seeder, whereas the 20?MHz fiber laser was amplified to 6?W. The femtosecond seeder allowed extracting Fourier-limited 4?ps pulses at 7?W output power. To our knowledge, these are the shortest pulses from any Nd:YVO₄ laser device with at least 7?W output power. This suggests a novel approach to exploit the gain bandwidth of vanadate amplifiers with high output power levels. Such amplifier technology promises to offer an interesting alternative to high-power thin disk oscillators at few picoseconds duration, as well as to regenerative amplifiers with low-repetition-rate fiber seeders.     

Diode-pumped Nd:YVO<Subscript>4</Subscript>-Nd:YLF blue laser at 488 nm by intracavity sum-frequency-mixing

We report a laser architecture to obtain continuous-wave blue radiation at 488 nm. A 808 nm diodepumped the Nd:YVO₄ crystal emitting at 914 nm. A part of the pump power was then absorbed by the Nd:YVO₄ crystal. The remaining was used to pump the Nd:YLF crystal emitting at 1047 nm. Intracavity sum-frequency mixing at 914 and 1047 nm was then realized in a LBO crystal to reach the blue radiation. We obtained a continuous-wave output power of 514 mW at 488 nm with a pump laser diode emitting 19.6 W at 808 nm.