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.     

High-peak-power,high-repetition-rate LD end-pumped Nd:YVO<Subscript>4</Subscript> burst mode laser

A compact high-peak-power, high-repetition-rate burst mode laser is achieved by an acousto-optical Q-switched Nd:YVO₄ 1064 nm laser directly pumped at 878.6 nm. Pulse trains with 10–100 pulses are obtained using acousto-optical Q-switch at repetition rates of 10–100 kHz under a pulsed pumping with a 1 ms duration. At the maximum pump energy of 108.5 mJ, the pulse energy of 10 kHz burst mode laser reaches 44 mJ corresponding to a single pulse energy of 4.4 mJ and an optical-to-optical efficiency of 40.5 %.The maximum peak power of ~468.1 kW at 10 kHz is obtained with a pulse width of 9.4 ns. The beam quality factor is measured to be M ² ~1.5 and the pulse jitter is estimated to be less than 1 % in both amplitude and time region.     

LD end-pumped passively mode-locked Nd:YVO<Subscript>4</Subscript> laser with single-walled carbon nanotubes

We demonstrate a LD end-pumped passively mode-locked Nd:YVO₄ laser using a single-walled carbon nanotubes saturable absorber (SWCNT-SA). The SWCNT wafer was fabricated by electric arc discharge method on quartz substrate with absorption wavelength of 1064 nm. At the absorbed pump of 15.8 W, an output power of 750 mW CW (continuous wave) mode-locked laser pulse was achieved with the repetition of 79.7 MHz, corresponding to optical-optical efficiency of 4.75%.     

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: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.     

Stationary generation of diode-pumped self-Raman Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> composite crystal laser

Output power dependences of composite Nd³⁺:YVO₄ Raman laser stationary generation on the longitudinal diode pump power are measured at different transmissions of the output mirror at the Stokes radiation frequency. The deviation of the measured dependences from linear is explained by the influence of thermal effects on both the overlap of the beams and diffraction losses. A method to estimate the laser and Stokes losses in the cavity and the parameters characterizing the overlap of the laser radiation with the pump and Stokes beams is proposed. A Stokes-component of power 2.1 W is obtained and corresponds to 12% diode-to-Stokes efficiency.     

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%.     

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%.     

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.     

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.     

High-power passively Q-switched Nd:YVO<Subscript>4</Subscript> UV laser at 355 nm

We report on an efficient high-power passively Q-switched UV laser at 355 nm. We take into account the second threshold criterion and the thermal-lensing effect to design and realize a compact reliable passively Q-switched Nd:YVO₄ laser with Cr⁴⁺:YAG as a saturable absorber. At an incident pump power of 16.3 W, the average output power at 1064 nm reaches 6.2 W with a pulse width of 7 ns and a pulse repetition rate of 56 kHz. Employing the developed passively Q-switched laser to perform the extra-cavity harmonic generations, the maximum average output powers at 532 nm and 355 nm are up to 2.2 W and 1.62 W, respectively.     

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.     

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.     

37 W 888-nm-pumped grown-together composite crystal YVO<Subscript>4</Subscript>/Nd:YVO<Subscript>4</Subscript>/YVO<Subscript>4</Subscript> oscillator at 1342 nm

We report on a continuous-wave Nd:YVO₄ oscillator at 1342 nm based on the combination of a grown-together composite crystal YVO₄/Nd:YVO₄/YVO₄ and the 888 nm diode-laser direct pumping for the first time. At the absorbed pump power of 102 W, a maximum average output power of 37.2 W at 1342 nm was obtained, corresponding to an optical-optical conversion efficiency of 36.5% and a high slope efficiency of 63.0%, respectively. To the best of our knowledge, this is the highest output power ever obtained for a 1342 nm Nd:YVO₄ oscillator.     

High efficiency,high repetition-rate Nd:YVO<Subscript>4</Subscript> laser with TEM<Subscript>00</Subscript> end-pumped by 887 nm

Thermal effect of laser crystal is a very important factor for solid lasers. The most of heat is generated from the quantum loss between pump light and lasing light. If a longer wavelength of pump light is adopted, quantum loss and quantum loss efficiency can be reduced and improved, respectively. In this paper, a Nd:YVO₄ laser end-pumped by 887 nm LD is reported. Output power of 25 W is obtained from a single Nd:YVO₄, when the crystal absorbs pump light power of 38 W. The corresponding opto-optic conversion efficiency is up to 65.7%. When 30.7 W pump light is absorbed in the crystal, 19.4 W TEM₀₀ is obtained with M _x ² = 1.30, M _y ² = 1.26 and opto-optic conversion efficiency of 63.2%. The laser can work at the Q-switched mode. The uniform pulses are generated at high repetition of 100 kHz. And the conditions of pulse stability are analyzed in this paper.     

Diode-pumped high-repetition-rate acousto-optically Q-switched Nd:YVO<Subscript>4</Subscript> laser operating at 914 nm

A diode-pumped high-repetition-rate acousto-optically (A-O) Q-switched Nd:YVO₄ laser operating at 914 nm was reported in this paper. Employing a compact linear laser cavity, at an operating repetition rate of 10 kHz, a maximum average output power of 2.2 W 914 nm laser was obtained at an incident pump power of 45.3 W, corresponding to an optical conversion efficiency of 4.9% and a slope efficiency of 8.8%. Minimum pulse width of 24 ns and maximum peak power of 8.0 kW of 914 nm laser was also achieved at an incident pump power of 40.8 W. To the best of our knowledge, this is the highest peak power of 914 nm laser at 10 kHz by far. Moreover, the highest operating repetition rate of pulsed 914 nm can even reach 100 kHz.     

Efficient continuouswave laser at 560 nm by intracavity frequency summation of fundamental and first-stokes wavelengths in a Nd:YVO<Subscript>4</Subscript>-BaWO<Subscript>4</Subscript> Raman laser

We report for the first time an efficient CW laser emission at 560 nm by sum-frequency mixing of the fundamental and first-Stokes fields generated within an Nd:YVO₄-BaWO₄ Raman laser. Intracavity sumfrequency mixing with LiB₃O₅ (LBO) nonlinear crystal yielded 1.12 W of visible yellow-green emission; the output power stability over 4 h is better than 3.3%. The laser beam quality M ² factors are 1.84 and 2.43 in both horizontal and vertical dimensions respectively.     

A novel prism beam-shaping laser diode bar end-pumped TEM<Subscript>00</Subscript> mode Nd:YVO<Subscript>4</Subscript> laser

A beam-shaping diode end-pumped TEM₀₀ mode CW Nd:YVO₄ laser is presented. A special beam-shaping element made up of isosceles right-angled prism pieces is adopted to realize beam symmetric. Two cylinder lenses are used to couple the shaped beam into a 3 × 3 × 9 mm Nd:YVO₄ crystal with 0.3 at % neodymium doping. By using this laser system, we have achieved 6.1 W CW laser operated in single transverse mode at 1064 nm with 95.2% reshaping efficiency and 25.6% optical-optical conversion efficiency.     

Compact efficient diode-end-pumped intracavity frequency-tripled Nd:YVO<Subscript>4</Subscript> 355 nm laser

A compact efficient diode-end-pumped acousto-optically Q-switched intracavity-frequency-tripled Nd:YVO₄ 355 μm ultraviolet laser was realized. Intracavity sub-resonators with anti-reflection and high-reflection coated mirrors were used to get higher efficiency of third harmonic generation. With two LBO crystals used in frequency doubling and tripling processes, greater than 1.46 W 355 nm average output power was obtained under the absorbed pump power of 13.9 W and the repetition rate of 10 kHz. The corresponding pump-to-ultraviolet conversion efficiency was determined to be as high as 10.5%. At 10 kHz, the minimize pulse width was obtained to be 12 ns with the peak power of 10.4 kW and single pulse energy of 146 μJ.     

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.