Highly efficient continuous-wave intracavity frequency-doubled Nd:YVO4-LBO laser at 457 nm under diode pumping into the emitting level 4F3/2

The continuous-wave high efficiency laser emission of Nd:YVO₄ at the fundamental wavelength of 914 nm and its 457 nm second harmonic obtained by intracavity frequency doubling with an LBO nonlinear crystal is investigated under pumping by diode laser at 880 nm into emitting level ⁴F_3/2. 6.5 W at 457 nm with M ²=1.8 was obtained from a 5-mm-thick 0.4 at.% Nd:YVO₄ laser medium and a 15-mm-long LBO nonlinear crystal in a Z-type cavity for 18.6 W absorbed pump power. An optical-to-optical efficiency with respect to the absorbed pump power was 0.35. Comparative results obtained for the pump with diode laser at 808 nm, into the highly-absorbing level ⁴F_5/2, are given in order to prove the advantages of the 880 nm wavelength pumping.     

Diode-pumped passively Q-switched Nd : YAG laser at 1123 nm

A diode-pumped Nd:YAG laser at 1123 nm is passively Q-switched by using a low doping concentration Cr⁴⁺:YAG crystal as a saturable absorber. When pumped by a 1.5-W laser diode, the laser produces pulses of 50-ns duration with a pulse energy of as much as 15 J and a peak power of 300 W at a pulse-repetition rate of 10 kHz. PACS 42.60.Gd; 42.55.Rz; 42.55.Xi     

High-energy directly diode-pumped Q-switched 1617 nm Er:YAG laser at room temperature

We describe high-energy Erbium-doped yttrium aluminum garnet (Er:YAG) lasers operating at 1617?nm, resonantly pumped using 1532?nm fiber-coupled laser diodes. A maximum continuous wave output power of 4.3?W at 1617?nm was achieved with an output coupler of 20% transmission under incident pump power of 29.7?W, resulting in an optical conversion of 14% with respect to the incident pump power. In Q-switched operation, the pulse energy of 11.8?mJ at 100?Hz pulse repetition frequency and 81?ns pulse duration was obtained. This energy is the highest pulse energy reported for a directly diode-pumped Q-switched Er:YAG laser operating at 1617?nm.     

3.1 W laser-diode-end-pumped composite Nd : YVO4 self-Raman laser at 1176 nm

We report a laser-diode-end-pumped acousto-optical Q-switched double-end diffusion-bonded Nd?:?YVO₄ self-Raman laser at 1176 nm. The maximum average output power at the first-Stokes wavelength of 1176 nm was obtained to be 3.1 W at the incident pump power of 25 W and the repetition rate of 90 kHz, with the corresponding optical conversion efficiency of 12.4%. The shortest pulse width, the maximum pulse energy and the highest peak power were measured to be 5 ns, 42 μJ and 7.5 kW, respectively.     

Highly efficient Nd:YAG ceramic CW laser with 59.8% slope-efficiency

In this paper, a highly efficient Ti:sapphire end-pumped 1 at.-% Nd:YAG ceramic laser that is comparable in efficiency with Nd:YAG single crystal lasers has been developed. Optical absorption and emission spectra for Nd:YAG ceramics have been measured. With 673-mW pumping, 295-mW laser output at 1064 nm has been obtained. The laser threshold is only 13 mW. Deducted the transmitted light, the corresponding optical-to-optical conversion efficiency is 58.4%. The lasing characteristics of Nd:YAG ceramic are nearly equal to those of Nd:YAG single crystal.     

High-peak-power passively Q-switched Nd:YAG laser at 946 nm

We demonstrate a high-peak-power quasi-continuous-wave diode-pumped passive Q-switched Nd:YAG laser at 946 nm. We make a thorough comparison of the output performance between the saturable absorbers of InGaAs quantum wells (QWs) and a Cr⁴⁺:YAG crystal. Experimental results reveal that the saturable absorber of InGaAs QWs is superior to the Cr⁴⁺:YAG crystal because of the low nonsaturable losses and leads to a pulse energy of 330 μJ with a peak power greater than 11 kW.     

1318.8 nm/1338.2 nm simultaneous dual-wavelength Q-switched Nd:YAG laser

A diode-side-pumped simultaneous dual-wavelength Q-switched Nd:YAG laser around 1.3 μm is demonstrated. With the pumping power of 480 W, a peak power of 43 kW was obtained at the repetition rate of 5 kHz. The maximum average output power is up to 43 W with the slope efficiency of 20.5%, and the pulse duration is 200 ns. This dual-wavelength Q-switched laser with high peak power has a balanceable and stable proportion of dual-wavelength output. PACS 42.55.Xi; 42.60.Gd     

Diode-pumped Q-switched Nd:YLF laser at 1313 nm

In this letter, we describe the operation of an end-pumped acousto-optic Q-switched Nd:YLF laser. According to the theoretical analysis and calculation for Nd:YLF crystal, the thermal focal length of σ-polarized laser is positive in plane-parallel resonator, while that of π-polarized laser is negative. Hence laser operation at σ-polarized 1313 nm should be stable in plane-parallel cavity. When absorbed pump power is 12.45 W and the pulse repetition frequency is 10 kHz, 3.1 W output laser at 1313 nm is achieved. As a result, the optical–optical conversion efficiency is 25.4 % and slope efficiency is 31.2 %, respectively.     

High-efficiency direct-pumped Nd:YLF laser operating at 1321 nm

We present a high-efficiency Nd: LiYF₄ (Nd:YLF) laser operating at 1321 nm pumped directly into the emitting level, ⁴F_3/2. The linear polarization of the pump diode laser was maintained by a short fiber. At the absorbed pump power of 7.3 W, as high as 3.6 W of continuous-wave output power at 1321 nm is achieved. The slope efficiency with respect to the absorbed pump power was 0.52. To the best of our knowledge, this is the first demonstration of such a laser system. Comparative results obtained for the pump with a diode laser at 806 nm, into the highly absorbing ⁴F_5/2 level, are given in order to prove the advantages of 880 nm wavelength pumping.     

QCW diode-side-pumped Nd:YAG ceramic laser with 247 W output power at 1123 nm

We demonstrate for the first time a diode-side-pumped quasi-continuous-wave (QCW) operation of a 1123 nm Nd:YAG ceramic laser. The single 1123 nm wavelength is acquired through precise coating. With a pump power of 1000 W, an output power of 247 W is obtained, corresponding to an optical–optical conversion efficiency of 24.7%. At the maximal output power, the pulse repetition rate and pulse width are measured to be 1.1 kHz and 180 μs, respectively. The numerical simulations for wavelength selectivity from 1112, 1116 and 1123 nm are discussed in detail.     

Study on CW Nd:YAG infrared laser at 1319 nm

A continuous wave (CW) Nd:YAG infrared laser at 1319 nm is reported in this paper. The energy level of 1319-nm wave was analyzed. The repression of 1064-nm lasing and enhancement of 1319-nm output power were discussed. Mirror coating and cavity structure were studied and a maximum CW output power of 43 W at 1319 nm was achieved in experiments.     

Quasi-three-level neodymium-doped yttrium aluminum garnet laser emitting at 885 nm

We present a diode-pumped quasi-three-level neodymium-doped yttrium aluminum garnet (Nd:YAG) laser at 885?nm, based on the F_3/24-I_9/24 transition, generally used for a 946?nm emission. Combined with polarization components (Nd:YAG), the electro-optical crystal KH₂PO₄ (KDP) formed a Lyot filter in the cavity and compressed the available gain bandwidth. With an incident pump power of 9.2?W, a 714?mW continuous-wave (CW) output at 885?nm was achieved, and the optical-to-optical efficiency was 7.8%. With an adjustable voltage applied to the KDP crystal, the laser wavelength could be tuned from 885?nm to 884?nm. A simultaneous dual-wavelength Nd:YAG laser at 885?nm and 884?nm was also realized by adjusting the free spectral range of the Lyot filter. To our knowledge, it is the first study that has realized the tuning between the 884 and 885?nm lines and the simultaneous dual-wavelength CW laser operation at 885?nm and 884?nm.     

Diode-pumped efficient continuous-wave Yb:Y3Ga5O12 laser at 1035 nm

An efficient diode-pumped Yb:Y3Ga5O12 (Yb:YGG) laser was demonstrated by using a high-quality Yb:YGG crystal grown by the optical floating zone method. Continuous-wave laser power up to 2.65?W had been obtained under an incident pump power of 6.71?W at 970?nm, corresponding to an optical-to-optical efficiency of 39.5% and maximum slope efficiency of 84.5%. A modeling calculation of the Yb:YGG laser was also performed, and the theoretical results were consistent with the experimental results.     

High power Nd:YAG slab laser sidepumped by diode laser array

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Diode-pumped Nd:YGG continuous-wave laser at 1.33 μm

We demonstrated a laser-diode pumped Nd-doped yttrium gallium garnet (Nd:YGG) crystal continuous wave (CW) laser at 1.33 μm for the first time to our knowledge. At an incident pump power of 18.5 W, as high as 3.09 W of CW output power at 1.33 μm is achieved. The slope efficiency with respect to the incident pump power was 21.3%, and the fluctuation of the output power was better than 2.8% in the given 4 h. The beam quality factor M² is 1.14 and 1.16 for tangential direction and sagittal direction, respectively.     

Laser operation at high repetition rate of 100 kHz in Nd:GdVO4 under 879 nm diode-laser pumping

Highly efficient continuous-wave and acousto-optically Q-switched laser emission in Nd:GdVO₄ crystal, end-pumped at 879 nm into the laser emitting level, are reported. A maximum cw output power of 13.3 W is obtained, corresponding to the slope efficiency of 74.6% in absorbed power; an average output power of 12.1 W, a pulse width of 20.3 ns and a peak power of about 6 kW are reached at 100 kHz in A-O Q-switched operation. PACS  42.55.-f; 42.55.Xi; 42.60.Gd