Passively Q-switched GdVO<Subscript>4</Subscript>/Nd:GdVO<Subscript>4</Subscript> laser with Cr<Superscript>4+</Superscript>:YAG saturable absorber under direct 879 nm diode pumping to the emitting level

A passively Q-switched 1.06 μm laser with Cr⁴⁺:YAG saturable absorber by direct 879 nm diode pumping grown-together composite GdVO₄/Nd:GdVO₄ crystal to the emitting level was demonstrated in this paper. The characteristics of pulsed laser were investigated by using two kinds of Cr⁴⁺:YAG crystal with the initial transmissivity of 80 and 90%, respectively. When the T ₀ = 90% Cr⁴⁺:YAG was used, an average output power of 1.59 W was achieved at an incident pump power of 10 W. The pulse width and repetition rate were 64.5 ns and 170 kHz, respectively. The thermal lens effect of laser crystal was analyzed.     

Compact passively Q-switched green laser with periodically poled MgO:LiNbO<Subscript>3</Subscript>

Passively Q-switched green output with Cr⁴⁺:YAG as saturable absorber and PPMgLN as the frequency doubling crystal was realized in a compact diode end-pumped Nd:YVO₄ laser. The green light output power, pulse width, pulse repetition rate, pulse energy and peak power with three Cr⁴⁺:YAG of different initial transmissions were investigated. The maximum average output power was 1.2 W at the pump power of 4.0 W and the maximum conversion efficiency was 30% with the Cr⁴⁺:YAG of 90% initial transmission. The maximum pulse energy and minimum pulse width were 10.9 μJ and 12 ns with the Cr⁴⁺:YAG of 75% initial transmission.     

Passive Q-switching of a laser-diode-pumped intracavity-frequency-doubling Nd:Nd<Superscript>3+</Superscript>:NaY(WO<Subscript>4</Subscript>)<Subscript>2</Subscript>/KTP laser with Cr<Superscript>4+</Superscript>:YAG saturable absorber

Nd³⁺:NaY(WO₄)₂, known as Nd:NYW, is a new type crystal. By using laser-diode as pump source, a passive Q-switching of intracavity-frequency-doubling Nd:NYW/KTP laser has been realized with Cr⁴⁺:YAG saturable absorber. The dependence of pulse repetition rate, pulse energy, pulse width, and peak power on incident pump power for different small-signal transmissions of Cr⁴⁺:YAG are measured. The coupled rate equations are used to simulate the Q-switched process of laser, and the numerical solutions agree with the experimental results.     

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.     

Diode-pumped Q-switched Nd:Y<Subscript>0.5</Subscript>Lu<Subscript>0.5</Subscript>VO<Subscript>4</Subscript> laser double-modulated with an acousto-optic modulator and Cr<Superscript>4+</Superscript>:YAG saturable absorber

A diode pumped Nd:Y_0.5Lu_0.5VO₄ pulse laser modulated with an acousto-optic (AO) Q-switcher and Cr⁴⁺:YAG saturable absorber is first demonstrated in this paper. The laser is shown to generate shorter pulse width than AO Q-switched laser alone, and have a higher peak power and single pulse energy than passively Q-switched laser with only Cr⁴⁺:YAG. A laser pulse width of 6.16 ns and a peak power of about 43.83 kW are achieved at the incident pumping power of 14.09 W.     

A laser-diode end-pumped passively Q-switched intracavity doubling Nd:GdVO<Subscript>4</Subscript>/KTP red laser with V<Superscript>3+</Superscript>:YAG saturable absorber

Using a V³⁺:YAG saturable absorber, we realize the running of a laser-diode end-pumped passively Q-switched intracavity-frequency-doubling Nd:GdVO₄/KTP red laser. Under the absorbed pump power of 9.45 W and with V³⁺:YAG initial transmission T ₀ = 94%, the obtained average output power and pulse width were 610 mW and 15.09 ns with the repetition rate of 12.2 kHz, corresponding to the single pulse energy 50 μJ and the pulse peak power 3.34 kW.     

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.     

High repetition rate passive Q-switching of diode-pumped Nd:GdVO<Subscript>4</Subscript> laser at 912 nm with V<Superscript>3+</Superscript>:YAG as the saturable absorber

The character of a diode-pumped passively Q-switched Nd:GdVO₄/V³⁺:YAG 912 nm laser was demonstrated for the first time to our knowledge. With an absorbed pump power of 7.4 W, an average output power of 360 mW with a Q-switched pulse width of 328 ns at a pulse repetition rate of 163 kHz was obtained. The Q-switching efficiency was found to be 32.7%. Our work further indicated V³⁺:YAG could be an effective fast passive Q-switch for 0.9 μm radiation.     

Passively Q-switched intracavity frequency-doubled Nd:LuVO<Subscript>4</Subscript>/LBO green laser with a Cr<Superscript>4+</Superscript>:YAG saturable absorber

This work presents experimental results concerning a passively Q-switched intracavity frequencydoubled Nd:LuVO₄/LBO green laser with a Cr⁴⁺:YAG saturable absorber operated at the wavelength of 0.53 μm. A maximal output power of 1.28 W was obtained at a pump power of 16.34 W, and peak power, pulse width as well as repetition frequency were 1.48 kW, 41 ns and 21 kHz, respectively.     

Passively Q-switched <Emphasis Type="Italic">a</Emphasis>-cut Nd:YVO<Subscript>4</Subscript> self-Raman laser

A passively Q-switched a-cut Nd:YVO₄ self-stimulating Raman laser using a Cr:YAG saturable absorber has been demonstrated for the first time. The maximum average output power of the self-Raman laser at 1176 nm is 347 mW at the incident pump power of 10 W with a pulse repetition frequency (PRF) of 66 kHz. The pulse width, pulse energy of the 1176 nm are found to be 10 ns and 5.6 μJ. The conversion efficiency from diode laser input power to Raman output power is 3.47%.     

An Intracavity-Triggered Passively-Switched Nd:YVO<Subscript>4</Subscript> Laser

We demonstrate an intracavity-triggered passively Q-switched Nd:YVO₄ laser within a diode-end-pumped configuration. We employ a Cr⁴⁺:YAG saturable absorber as the passive Q switch and an Nd:LiYF₄ (YLF) laser as the laser triggering of the Q-switched laser. Since we use the same Cr⁴⁺:YAG crystal and output coupler with the Nd:YVO₄ laser, the Cr⁴⁺:YAG Q switch is triggered inside the Nd:YLF laser cavity. As a result, the timing jitter in standard deviation of Nd:YVO₄ laser can be reduced to 16 ns.     

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 passively Q-switched and Q-switch mode-locked Nd:YVO<Subscript>4</Subscript> laser using single-wall carbon nanotube based saturable absorber

We present the performance of diode end-pumped Nd:YVO₄ laser in Q-switched and Q-switched mode-locking oscillation using a single-walled carbon nanotube based saturable absorber, which was fabricated using similar vertical evaporation technique. The average output power, repetition rate and pulse width of the Q-switched laser output were studied with different output couplers. The maximum average output power was 130 mW. For Q-switched mode-locking operation, the repetition rate of the mode-locked pulses concentrated in the Q-switched envelope was 58 MHz. The repetition rate of the Q-switched envelope maintained at 18 kHz, while the pulse width decreased along with the increasing of pump power. The maximum average output power was 53 mW.     

Single diode-pumped, 1.7 ns microchip laser by Nd:YAG/Cr<Superscript>4+</Superscript>:YAG composite crystal

A single diode-pumped passively Q-switched composite Nd:YAG/Cr⁴⁺:YAG laser, which cavity mirrors were deposited directly onto the crystal, was demonstrated in this paper. At the incident power of 2.75 W, the maximum average output power of 365 mW and the shortest pulse width of 1.7 ns were obtained, corresponding the repetition rate of 14.6 kHz. The single-pulse energy and the peak power were estimated to be 25 μJ and 14 kW, respectively. The corresponding optical-optical conversion efficiency was 13.3%.     

Passively Q-switched mode-locking in a diode-pumped Nd:LuVO<Subscript>4</Subscript> laser with V:YAG

A passively Q-switched and mode-locked Nd:LuVO₄ laser with V:YAG at 1.34 μm was successfully demonstrated. Comparisons between c-cut and a-cut Nd:LuVO₄ lasers were experimentally made. The maximum average output power of 170 mW, the highest Q-switched pulse energy of 4.5 μJ were obtained in c-cut Nd:LuVO₄ laser. The duration of mode-locked pulse was estimated to be less than 540 ps with repetition rate of 110 MHz.     

Diode-pumped doubly Q-switched YVO4/Nd:YVO4 laser with BBO electric-optic Q-switch and Cr4+:YAG saturable absorber

In the experiment, we have demonstrated the performance of a laser-diode, end-pumped, doubly Q-switched YVO₄/Nd:YVO₄ laser with both a BBO electric-optic (EO) Q-switch and Cr⁴⁺:YAG saturable absorber. At a maximum incident pump power of 15 W and an EO Q-switch repetition rate of 8 kHz, the stable laser pulses with the pulse duration 5.28 ns, the single pulse energy 0.14 mJ, and the pulse peak power 26 kW are obtained. The experimental results show that the double Q-switched laser with EO and Cr⁴⁺:YAG can generate the shorter pulse and the higher peak power in comparison to singly Q-switched laser with EO.     

Continuous wave and passively Q-switched laser performance of a composite crystal bonded with three Nd:YVO<Subscript>4</Subscript> single crystals

The laser performance of a composite crystal bonded with three Nd:YVO₄ single crystals has been investigated for the first time as far as we know. The largest continuous wave output power of 2.68 W is obtained at the incident pump power of 6.2 W, giving an optical conversion efficiency of 43.1% and a slope efficiency of 45.9%. For passively Q-switched operation with Cr⁴⁺:YAG of 71% initial transmission, the shortest pulse width of 18.2 ns, the largest single-pulse energy of 19.9 μJ, and the highest peak power of 1.12 kW are achieved, with the pulse repetition rate being 44.9 kHz, at the incident pump power of 6.2 W. The composite crystal can generate more excellent laser performance, when compared with the single crystals.     

Passively Q-switched laser performance of a diode-pump mixed Nd:Lu<Subscript>0.15</Subscript>Y<Subscript>0.85</Subscript>VO<Subscript>4</Subscript> crystal

A diode-pumped passively Q-switched Nd:Lu_0.15Y_0.85VO₄ laser with a GaAs output coupler is demonstrated. By using a mixed crystal Nd:Lu_0.15Y_0.85VO₄ as laser medium, the passively Q-switched laser can generate shorter pulse width with higher peak power in comparison with the passively Q-switched Nd:LuVO₄ or Nd:YVO₄ lasers under the same laser cavity. At the incident pump power 11.9 W, the minimum pulse width of 3.23 ns and the maximum peak power 1.67 kW can be obtained. The average output power and the pulse repetition rate of the laser are also measured. The experimental results show that the mixed crystal is a promising laser medium for shorter Q-switched pulse with higher peak power.     

Pulse compression in diode-pumped doubly Q-switched Nd:GdVO<Subscript>4</Subscript> laser with both V<Superscript>3+</Superscript>:YAG and Co<Superscript>2+</Superscript>:LMA saturable absorber

By simultaneously using both a V³⁺:YAG and a Co²⁺:LaMgAl₁₁O₁₉ saturable absorber in the cavity, for the first time to our knowledge, a diode-pumped doubly Q-switched Nd:GdVO₄ laser has been realized. The dependence of pulse width, pulse repetition rate, pulse energy and peak power on the incident pump power are measured. Under the absorbed pump power of 8.59 W, both the pulse temporal profile of the passive double-switching with the pulse width of 25.29 ns, and the passive single-switching just using V³⁺:YAG with pulse width of 30.46 ns are obtained. The pulse duration is partly compressed in contrast to the purely passively Q-switched laser with V³⁺:YAG.     

Passively Q-Switched and mode-locked Nd:YVO<Subscript>4</Subscript> laser with sandwich structured wallpaper graphene oxide absorber

We report on a passively Q-switched and mode-locked Nd:YVO₄ laser using a novel low-cost wall-paper graphene oxide absorber. Sandwich structured wallpaper graphene oxide absorber was constructed by a high transmission mirror, a piece of wallpaper graphene oxide absorber and a reflective mirror. The average output power of 310 mW of passively Q-switched and mode-locked laser was successfully achieved. The repetition rate and pulse width of the Q-switched envelope were 213 kHz and 770 ns, respectively. The repetition rate of passively mode-locked pulse within the Q-switched envelope was 81.3 MHz with the pulse energy of 3.8 nJ.