3.62 W of continuous-wave orange-yellow light generated by intra-cavity sum-frequency mixing of Nd:YVO4

A design of laser-diode array (LDA) end-pumped Nd:YVO₄ laser that generates simultaneous laser action at wavelengths 1064 and 1342 nm is presented. Using type-I critical phase matching (CPM) BiB₃O₆, 593.5 nm continuous-wave (cw) Orange-yellow laser is obtained by 1064 nm and 1342 nm in an intra-cavity sum-frequency mixing. The maximum laser output power of 3.62 W is obtained when an incident pump laser of 27.5 W is used. The optical-to-optical conversion is up to 13.2%. To the best of our knowledge, this is the highest conversion efficiency at 593.5 nm in an intra-cavity sum-frequency Nd:YVO₄ laser.     

High-efficiency direct-pumped Nd:YVO4-LBO laser operating at 671 nm

The continuous-wave high-efficiency laser emission from Nd:YVO₄ at the fundamental wavelength of 1342 nm and its 671 nm second harmonic obtained by intra-cavity frequency doubling in an LBO nonlinear crystal are investigated under pumping by diode laser at 880 nm (on the ⁴F_3/2→⁴I_13/2 transition). The end-pumped Nd:YVO₄ crystal yielded a continuous-wave output power of 9.6 W at 1342 nm for 18.9 W of absorbed pump power. The slope efficiency measured with respect to the absorbed pump power is 60%. An output of 5.5 W at 671 nm was obtained by frequency doubling, resulting in an optical-to-optical efficiency with respect to the absorbed pump power of 29%. Comparative results obtained for the pump with a diode laser at 808 nm (on the ⁴F_5/2→⁴I_13/2 transition) are given in order to prove the advantages of the 880 nm wavelength pumping.     

A comparative study of continuous laser operation on the F3/2-I9/2 transitions of Nd:GdVO4 and Nd:YVO4 crystals

A comparative study of Nd:GdVO₄ and Nd:YVO₄ crystal lasers pumped by a fiber-coupled diode array has been conducted at the ⁴F_3/2-⁴I_9/2 transitions wavelengths of 912 nm and 914 nm, as well as when intracavity frequency-doubled to 456 nm and 457 nm, respectively. At the fundamental wavelength of 912 nm and second harmonic wavelength of 456 nm, maximum output powers from the Nd:GdVO₄ crystal laser were 7.85 W and 4.6 W at a pump power of 29 W. All the results obtained from Nd:GdVO₄ were superior to those of Nd:YVO₄, indicating that Nd:GdVO₄ is a more efficient laser crystal than Nd:YVO₄ for laser operation on the ⁴F_3/2-⁴I_9/2 transitions.     

All-solid-state doubly resonant sum-frequency mixing laser at 555 nm

We report for the first time a coherent radiation at 555 nm by intracavity sum-frequency generation of 946 nm Nd:YAG laser and 1343 nm Nd:LuVO₄ laser. Yellow-green laser is obtained by using a doubly folded cavity, type-II critical phase matching KTP crystal sum-frequency mixing. With total pump power of 31.9 W (13.7 W pump power for 1343 nm Nd:LuVO₄ laser and 18.2 W pump power for 946 nm Nd:YAG laser), TEM₀₀ mode yellow-green laser at 555 nm of 2.35 W is obtained.     

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.     

Diode-pumped eye sensitive laser at 554.7 nm based on intracavity sum frequency generation

We report for the first time a coherent radiation at 554.7 nm by intracavity sum-frequency generation of 946 nm Nd:YAG laser and 1341 nm Nd:YAP laser. Yellow-green laser is obtained by using a doubly folded cavity, type-II critical phase matching KTP crystal sum-frequency mixing. With total pump power of 36.1 W (17.8 W pump power for 1341 nm Nd:YAP laser and 18.3 W pump power for 946 nm Nd:YAG laser), TEM₀₀ mode yellow-green laser at 554.7 nm of 1.43 W is obtained.     

Diode-pumped 593.5 nm cw yellow laser by type-I CPM LBO intracavity sum-frequency-mixing

A design of LD-pumped Nd:YVO₄ laser that generates simultaneous laser action at wavelengths 1064 and 1342 nm by optimizing film design is presented. An optimized continuous-wave (cw) yellow laser at 593.5 nm in room temperature is obtained for the first time. Using type-I critical phase-matching (CPM)LBO crystal, a yellow laser at 593.5 nm is obtained by 1064 and 1342 nm intracavity sum-frequency mixing. The maximum laser output power of 85 mW is obtained when an incident pump laser of 1.8 W is used. The optical-to-optical conversion is up to 4.7%, and the power stability in 24 h is better than ±2.8%.     

Quasi-three-level Nd:YAG laser under diode pumping directly into the emitting level

We present theoretical and experimental investigations on ground-state direct pumping at 869 nm into the emitting level ⁴F_3/2 of end-pumped quasi-three-level Nd:YAG lasers operating at 946 nm. We have demonstrated, what we believe is for the first time, a Nd:YAG laser at 946 nm directly pumped by diodes and obtained 1.6 W of output power.     

A comprehensive study of Nd:YAG, Nd:YAlO3, Nd:YVO4 and Nd:YGdVO4 lasers operating at wavelengths of 0.9 and 1.3 μm. Part 1: cw-operation

This paper reports on efficient generation of cw laser radiation at 0.9 and 1.3 μm in different neodymium doped laser hosts. The thermal, mechanical and optical properties as well as the laser performance of Nd:YAG, Nd:YAlO₃, Nd:YVO₄ and Nd:GdVO₄ are studied in numerical simulations as well as in experimental investigations. For example an output power of more than 4.0 W is generated in Nd:YVO₄ at the 914 nm ⁴F_3/2→⁴I_9/2 transition using a pump power of 19 W. In Nd:GdVO₄ more than 6.0 W are obtained at the 1342 nm ⁴F_3/2→⁴I_13/2 laser transition by using a pump power of 19.3 W. The spatial beam quality of both lasers is diffraction limited with an M² value of less than 1.1. PACS  42.70.Hj; 42.55.Xi; 42.60.Pk     

High-power continuous-wave doubly resonant all-intracavity sum-frequency mixing deep blue laser at 447 nm

In this paper, a high-power continuous-wave deep blue laser at 447 nm with intracavity tripling was achieved. The deep blue laser at 447 nm is obtained by using a doubly cavity, and type-II critical phase matching KTP crystal for intracavity sum-frequency mixing. Through designing of the cavity, the optimum matching of modes and gains for the two wavelengths was obtained. With incident pump power of 30 W for the Nd:YVO₄ crystal and 16 W for the other Nd:YVO₄ crystal, the deep blue laser output of 3.5 W at 447 nm with TEM₀₀ mode was obtained, the beam quality M² value was equal to 1.8 in both horizontal and vertical directions at the maximum output power, and the power stability is better than 3% at the maximum output power during half an hour. The experimental results show that the intracavity sum-frequency mixing by doubly resonant is an effective method for high-power blue laser.     

Diode-pumped passively Q-switched Nd:GdVO4 laser at 1342 nm with V:YAG saturable absorber

We have demonstrated an efficient diode-pumped passively Q-switched Nd:GdVO₄ laser working at 1342 nm by using an uncoated V³⁺:YAG crystal as the saturable absorber, in which both a-cut and c-cut Nd:GdVO₄ crystals are employed. At the maximum absorbed pump power of 9.45 W, the maximum average output power can reach 519 mW and 441 mW corresponding to the output coupler with different transmission of 3% and 10% by using an a-cut Nd:GdVO₄ crystal at 1342 nm, while the shortest pulse duration could be as low as 21.7 ns and 22.3 ns with the repetition rate of 48.41 kHz and 53.25 kHz by using a c-cut Nd:GdVO₄ crystal, corresponding to the output coupler with different transmission of 3% and 10% at 1342 nm, and the single Q-switched pulse energy are 6.67 uJ and 7.06 uJ, the pulse peak power are 307 W and 316 W, respectively. The experimental results show that c-cut Nd:GdVO₄ laser can generate shorter pulse with higher peak power in comparison with a-cut one.     

All-solid-state doubly resonant sum-frequency continuous-wave laser at 555 nm

A new kind of resonator for doubly resonant continuous-wave (CW) intracavity sum-frequency mixing(SFM) is presented. A coherent radiation of 327 mW at 555 nm is generated by mixing 1342-nm Nd:YVO4 laser and 946-nm Nd:YAG laser. The M2 beam quality factor of the sum-frequency mixed yellow-green laser is less than 1.7. The low-noise characteristic of the yellow laser is demonitrated.     

End-pumped 20.2-W Nd:YVO4 cw slab laser at 1342 nm with a hybrid resonator

A 20.2 W laser-diode-end-pumped Nd:YVO₄ slab laser with a hybrid resonator at 1342 nm was demonstrated. The slope efficiency and optical-to-optical conversation efficiency were 30% and 23%, respectively. At output power of 16 W, the M² factor in stable direction was 2.3, and in the unstable direction was 1.2.     

43 W picosecond laser and second-harmonic generation experiment

Combining the advantages of diode-end-pumped Nd: YVO₄ and diode-side-pumped Nd: YAG amplifiers, a high average power and high beam quality picosecond laser is designed. The system delivers a picosecond laser with average power of 43.4 W and good beam quality of M² < 1.7. By focusing the high power picosecond laser in LBO crystal, 532 nm green laser with maximal power of 20.8 W is generated and the conversion efficiency of second-harmonic generation reaches 56.4% when 17.7 W green laser obtained from the fundamental frequency laser with power of 31.4 W and beam quality of M² < 1.25.     

Simultaneous dual-wavelength emission at 0.90 and 1.06 µm in Nd-doped laser crystals

Continuous-wave (CW) simultaneous laser emission on the 0.9-μm ⁴ F _3/2 → ⁴ I _9/2 transition and the ⁴ F _3/2 → ⁴ I _11/2 transition at 1.06 μm is obtained in Nd-based laser crystals of thin-disk geometry and using a multi-pass pumping scheme. A Nd:Y₃Al₅O₁₂ (Nd:YAG) thin disk emitted simultaneous laser radiation at 946 and 1064 nm with 5.1 W output power, and Nd:YVO₄ and Nd:GdVO₄ thin-disk lasers with more than 3 W output power at 0.91 and 1.06 μm were realized. The ratio between the output power at one of the wavelengths and the total output power could be varied by the laser resonator design. An intracavity frequency-doubled Nd:YVO₄ thin-disk laser with alternate green at 532 nm and “deep-blue” at 457 nm generation of high average output powers is demonstrated.     

Diode-pumped Nd:YVO4-Nd:CNGG crystals blue laser at 462 nm by intracavity sum-frequency-mixing

We report a laser architecture to obtain continuous-wave (cw) blue radiation at 462 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:CNGG crystal emitting at 935 nm. Intracavity sum-frequency mixing at 914 and 935 nm was then realized in a LiB₃O₅ (LBO) crystal to reach the blue radiation. We obtained a continuous-wave output power of 892 mW at 462 nm with a pump laser diode emitting 18.4 W at 808 nm.     

Picosecond laser amplification system with 93 W high average power

A high average power picosecond laser amplification system with diode-end-pumped Nd:YVO₄ and diode-side-pumped Nd:YAG is described. Laser with power up to 92.7 W, repetition frequency of 73.3 MHz, pulse duration of 26.5 ps, and beam quality of M² < 3.5 is generated in the amplification system. Thermal-birefringence-induced depolarization in the Nd:YAG rod laser head amplifier is measured to be 21.9 W though birefringence compensation is performed.     

High-efficiency Nd:YVO4 laser emission under direct pumping at 880 nm

We report a high-efficiency Nd:YVO₄ laser pumped by an all-solid-state Q-switched Ti:Sapphire laser at 880 nm in this paper. Output power at 1064 nm with different-doped Nd:YVO₄ crystals of 0.4-, 1.0- and 3.0-at.% under the 880 nm pumping was measured, respectively. Comparative results obtained by the traditional pumping at 808 nm into the highly absorbing ⁴F_5/2 level were presented, showing that the slope efficiency and the threshold with respect to the absorbed pump power of the 1.0-at.% Nd:YVO₄ laser under the 880 nm pumping was 17.5% higher and 11.5% lower than those of 808 nm pumping. In a 4-mm-thick, 1.0-at.% Nd:YVO₄ crystal, a high slope efficiency of 75% was achieved under the 880 nm pumping, with an optical-to-optical conversion efficiency of 52.4%.     

Efficient dual-wavelength Nd:YVO4 laser at 1085 and 1342 nm and sum-frequency mixing for an orange emission

We report on the efficient continuous-wave (CW) dual-wavelength operation of a Nd:YVO₄ laser at 1085 and 1342 nm. An output power of 1.72 W for the dual-wavelength was achieved at the incident pump power of 17.4 W. Intracavity sum-frequency mixing at 1085 and 1342 nm was then realized in a KTP crystal to reach the orange range. A maximum output power of 146 mW in the orange spectral range at 600 nm has been achieved. The orange output stability is better than 3.8%. The orange beam quality M ² value is about 1.41 and 1.25 in both horizontal and vertical dimensions, respectively.     

LBO Ⅰ类临界相位匹配内腔和频555 nm激光器

报道了全固态连续波555 nm激光器.555 nm激光是分别由Nd:YAG和Nd:YVO4晶体的946 nm和1342 nm谱线非线性和频产生,两条谱线在各自晶体对应能级跃迁分别为4F3/2-4Ⅰ9/2和4F3/2-4Ⅰ13/2.实验中采用复合折叠腔结构,利用LBOI类临界相位进行腔内和频,当注入Nd:YAG和Nd:YVO4晶体的泵浦功率分别为20 W和10 W时,获得1.06 W的TEM00连续波555 nm激光输出.4小时功率稳定度优于±3.3%.实验结果表明采用两种激光晶体进行腔内和频是获得激光的高效方法,并可以应用到其它两种激光晶体进行腔内非线性和频,获得更多不同波长激光输出.