Green Beam Generation Research Articles

260 W of average green beam generation by intracavity frequency-doubled acousto-optic Q-Switched Nd:YAG laser

We developed an intracavity frequency-doubled acousto-optic Q-switched Nd:YAG laser generating ~ 260 W of average green power using two identical diode-pumped gain modules with fivefold pumping symmetry in a simple two mirror linear cavity configuration. The corresponding optical to optical conversion efficiency was estimated to be ~ 16.8%. At maximum output power, individual green pulse duration (FWHM) was measured to be ~ 73 ns with a pulse repetition rate of 18 kHz. The output average green power was highly stable with measured fluctuation in average green power ± 0.83 W over 5 h of continuous operation. The jitter in pulse delay time and pulse to pulse amplitude fluctuation was measured to be within ± 4.25 ns and ± 5%, respectively. The maximum beam drift recorded at 5 m distance away from the laser system was ~ 14 micron corresponding to beam pointing stability of ± 2.8 micro-rad.

82 W Continuous-Wave Green Beam Generation by Intracavity Frequency Doubling of Diode-Side-Pumped Nd:YAG Laser

Highly efficient and high-power continuous-wave (CW) green beam generation by intracavity frequency doubling of diode side-pumped Nd:YAG laser using a water cooled high gray track resistant potassium titanyl phosphate crystal is demonstrated in a Z-shaped resonator design ensuring resonator stability over the entire range of the pump power with optimized spot sizes at the respective intracavity components configuration. A maximum of 82.5 W of CW green power was obtained at a total diode pumping power of 750 W, corresponding to 11% pump to green beam conversion efficiency. The green power increases linearly with pump power without any sign of power rolloff, and no damage of the crystal due to thermal lensing or gray tracking is observed. The long-term stability is excellent with ±0.7% variation in the output power. The short-term rms intensity fluctuation is measured to be ±0.2%. The performance of the laser by considering the pump-power-induced thermal lensing effect and the M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> parameter at the fundamental wavelength has been analyzed. The theoretical model showed excellent agreement with the experimental results.

Efficient and high-power green beam generation by frequency doubling of acousto-optic Q-switched diode-side pumped Nd:YAG rod laser in a coupled cavity

A 52-W green laser at 532 nm by extra-cavity second-harmonic generation in a coupled-cavity configuration is demonstrated. The fundamental laser is a diode-side-pumped acousto-optic (AO) Q-switched Nd:YAG rod laser producing 84 W of average power at 1064 nm at 8 kHz repetition rate. Type-II phase-matched polished KTP crystal is used as the nonlinear crystal for second-harmonic generation. The individual green pulse width is 50 ns and the fundamental to second harmonic conversion efficiency is 61.8%.

High-power continuous wave green beam generation by use of simple linear cavity with side-pumped module

High-power continuous wave green radiation has been generated by means of type-II phase-matched frequency doubling in a KTP crystal located in a simple linear cavity incorporating a diode side-pumped Nd:YAG laser module. The cavity was designed to make the fundamental beam radius at the KTP crystal smaller than that at the gain medium, as is required for obtaining large mode volume in Nd:YAG crystal and realizing efficient CW intracavity frequency doubling. Output power of 51.2 W is obtained in the experiment with a diode-to-green optical conversion efficiency of 10.3%. The M 2-parameters of the laser are measured at different output powers. For the output power of about 47 W, the power fluctuation is measured less than 1%. The experimental results show that the continuous wave green laser system using this simple linear cavity offers good laser performance and output stability.

Green-Beam Generation of 40 W by Use of an Intracavity Frequency-Doubled Diode Side-Pumped Nd:YAG Laser

A cw diode side-pumped Nd:YAG laser is frequency doubled to 532nm with an intracavity KTP crystal in a V-shaped arrangement, achieving an output power of 40 W corresponding to an optical–optical conversion efficiency of 9.7%. The instabilities and the M2 -parameters of the laser are measured at different output powers after the beam is filtered.

High average power Q-switched green beam generation by intracavity frequency doubling of diode-side-pumped Nd:YAG/HGTR-KTP laser

To obtain high power and high beam quality second harmonic generation, a Q-switched system has been demonstrated by intracavity frequency doubling of two diode-side-pumped Nd:YAG modules with double AO-modulators in an astigmatism compensated cavity geometry. A maximum average frequency doubled power of 185 W is obtained when the pumping power is 600 W for each module. The corresponding optical-to-optical conversion efficiency is 15.4% and the pulse width is 180 ns at a repetition rate of 10 kHz. An instability of 2.5% was measured over a period of 2 h and the beam quality factors were measured to be M x 2 = 9.52 , M y 2 = 9.86 the maximum output power.

High-power and high-quality, green-beam generation by employing a thermally near-unstable resonator design

We have obtained green-beam quality of M2 = 6.2 at an average output power of 120 W by intracavity frequency doubling of a diode-side-pumped, Q-switched Nd:YAG rod laser with a repetition rate of 10 kHz and an optical-to-optical conversion efficiency of 15.2%. To achieve high-beam quality at high average power, the laser employs a thermally near-unstable resonator design with two-rod birefringence compensation in an L-shaped flat-flat cavity. The output power fluctuation of the green laser remains less than 0.9% in 4 h.

Efficient and high-power intracavity frequency doubled diode-side-pumped Nd:YAG/KTP continuous wave (CW) green laser

Highly efficient continuous wave (CW) green beam generation by intracavity frequency doubling of a diode side-pumped Nd:YAG laser using a single pump head based on a copper-coated flow tube in a V-shaped cavity geometry has been demonstrated. A maximum 30.5W of CW green power was obtained at a total diode pumping power of 260W corresponding to 11.7% conversion efficiency of diode pump power to CW green power and 4.7% conversion efficiency of electrical power to CW green power. The performance of the laser by considering the pump power induced thermal lensing effect and the M2-parameter at the fundamental wavelength has been analyzed.

High Beam Quality Green Generation with Output 140 W Based on aThermally-Near-Unstable Flat–Flat Resonator

By using a diode-side-pumped Q-switched Nd:YAG rod laser based on athermally-near-unstable flat–flat resonator, anintracavity-frequency-doubled green beam generation is investigated.Output power 140 W is obtained at a repetition rate of 10 kHz and apulse width of 110 ns. The green beam quality factors M2x andM2y, which are measured by a laser beam analyser, are 10.65 and10.85, respectively, at output power of 124 W.

Efficient high-pulse-energy green-beam generation by intracavity frequency doubling of a quasi-continuous-wave laser-diode-pumped Nd:YAG laser

A 50-mJ green beam was generated at a 1-kHz repetition rate by intracavity frequency doubling of a quasi-cw laser-diode-pumped Nd:YAG laser. The green laser was used for 12-mJ fourth-harmonic beam generation with a CsLiB(6)O(10) crystal.

Highly efficient 68-W green-beam generation by use of an intracavity frequency-doubled diode side-pumped Q-switched Nd:YAG rod laser

An intracavity frequency-doubled diode side-pumped Nd:YAG laser was developed by use of an advanced cavity configuration and a diffusive close-coupled side-pumping design. A maximum green power of 68 W was generated at a 20-kHz repetition rate with 18.4% optical-to-optical conversion efficiency and 7.1% electrical-to-optical conversion efficiency.

Efficient high-power green beam generation by use of an intracavity frequency-doubled laser-diode-pumped Q-switched Nd:YAG laser

An intracavity frequency-doubled diode-side-pumped Nd:YAG laser has been developed. A maximum green power of 20 W was generated at 20-kHz repetition rate with 14.2% optical-to-optical conversion efficiency and 5.3% electrical-to-optical conversion efficiency.

High-power green-beam generation in continuous-wave modes by use of long KTiOPO_4 crystals with a Nd:YAG laser

We report the generation of 24-W green power, which, to our knowledge, is the highest level of green power achieved in cw modes. Intracavity frequency doubling of a simple Nd:YAG laser was performed with a 15-mm KTiOPO(4) crystal. The green power was stable, and the highest level of green power achievable was limited only by the maximum lamp input power. We obtained a similar level of green power by replacing the single 15-mm KTiOPO(4) crystal by a phase-unified multinonlinear crystal combination consisting of a 5-mm and a 10-mm KTiOPO(4) crystal.