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 , the maximum output power.     

Efficient generation of blue light by intracavity frequency doubling of a cw Nd:YAG laser with LBO

We report on the efficient room-temperature operation of ⁴F_3/2–⁴I_9/2 transition in a diode pumped Nd:YAG laser operating at 946 nm. An output power of 5.1 W and a slope efficiency of 23.6% at 946 nm have been obtained. Different LBO crystals of length 3×3×10 mm³, 3×3×15 mm³, 3×3×18 mm³ were selected as frequency doubling material for comparison. A maximum single-ended output power of 1.3 W at 473 nm was achieved by frequency doubling with an optical conversion efficiency of 5%. When the Nd:YAG rod was replaced by the one with high reflectivity coating at 473 nm on the pump side, the output power of blue light was almost twice that without high reflectivity coating for 473 nm at the same pump power level. Moreover, the theoretical optimum length of LBO crystal for intracavity frequency doubling was discussed, and the experimental results made a good agreement with it.     

Efficient intra-cavity second harmonic generation by a diode-pumped actively Q-switched Nd:YAG laser

A compact and efficient intra-cavity doubled, actively Q-switched diode-pumped Nd:YAG laser has been developed. It generates as much as 1.55 W at 532 nm, with pulses of 400 ns at a repetition rate of 15 kHz, with an overall optical-to-optical efficiency of 15.5%. A beam quality factor M² ≈ 2.35 has been measured at this power level.     

Highly efficient 1181 nm output from a transversely diode-pumped Nd:KGd(WO4)2 self-stimulating Raman laser

We have achieved high average power Raman output from a compact, diode-pumped, self-stimulating Nd³⁺:KGd(WO₄)₂ Raman laser. Maximum Raman output power of 0.8 W was achieved at a pulse repetition frequency (PRF) of 2 kHz. The optical efficiency from diode to Raman laser was 14%. By generating extra-cavity second harmonics using a LiB₃O₅ crystal, it was possible to produce 0.2 W yellow output. The laser system was simulated numerically using rate equations and the results obtained were in good agreement with the experimental results.     

200 MHz CW mode-locked KTP intracavity frequency-doubled Nd:YAG laser

Experimental results of 200 MHz CW actively mode-locked KTP two-pass in-tracavity frequency-doubled Nd:YAG laser are reported.The primary factors influencingthe continuous-wave frequency-doubled conversion efficiency are analyzed.High efficiencylaser output was achieved by L-type folded-arm-cavity two-pass frequency-doubling.15 Waverage mode-locked power and 1.5W average mode-locked SHG green light output were ob-tained at 3.5kW single lamp input power respectively.     

Five-hundred-milliwatts distributed-feedback diode laser emitting at 940 nm

A DFB laser emitting at a wavelength around 940 nm in a single longitudinal mode up to an output power of 500 mW with a side mode suppression ratio greater than 50 dB is presented. More than 4 nm tuning range was reached by varying the current between 100 and 800 mA. Up to a power of about 300 mW, the lateral far field revealed stable fundamental mode operation.     

Yellow light generation by frequency doubling of a diode-pumped Nd:YAG laser

We demonstrate the generation of TEM₀₀ mode yellow light in critically type II phase-matched KTiOPO₄ (KTP) with intracavity frequency doubling of a diode-pumped Nd:YAG laser at room temperature. After a 150 μm thick etalon have been inserted into the cavity, the stability and beam quality of the second harmonic generation (SHG) is enhanced. A continuous wave (CW) TEM₀₀ mode output power of 1.67 W at 556 nm is obtained at a pump level of 16 W. The total optical to optical conversion efficiency is about 10.44%. To the best of our knowledge, this is the first Watt-level yellow light generation by frequency doubling of Nd:YAG laser.     

LD侧泵Nd:YAG/S-KTP腔内倍频高功率660 nm连续红光激光器

报道了LD侧面泵浦NdYAG/S-KTP腔内倍频高功率660 nm连续红光激光器.泵浦组件(呈三角形等间距分布)由9个20 W的激光二极管组成,最大泵浦功率为180 W.通过对谐振腔参数进行优化设计,用LD连续抽运3 mm×65 mm NdYAG激光棒时,获得了波长为1 319 nm的基频光振荡.利用S-KTP Ⅱ类临界相位匹配腔内倍频技术,当泵浦电流为22 A时,获得了6.8 W的连续红光激光输出,光-光转换效率为4.3%.     

Efficient 1047 nm CW laser emission of Nd:YLF under direct pumping into the emitting level

We demonstrate a 1047 nm Nd:LiYF₄ (Nd:YLF) laser by directly pumping into the upper lasing level with a tunable Ti:Sapphire laser. The results obtained for direct upper laser level pumping at 863, 872 and 880 nm of Nd:YLF were compared with traditional 806 nm pump band excitation. Highly efficient 1047 nm continuous-wave (CW) laser emission under direct pumping at 880 nm in an 8 mm thick, 1.0 at.% Nd:YLF crystal is obtained. The slope efficiency is improved from 55.6% for traditional pumping at 806 nm to 76.3% for direct pumping at 880 nm.     

Diode-end-pumped composite Nd:YVO4 yellow laser based on intracavity frequency-doubled self-Raman laser

We report an intracavity frequency-doubled Q-switched self-Raman yellow laser at 587 nm. A composite Nd:YVO₄ crystal was utilized as self-Raman gain medium. The maximum average output power of yellow light obtained was 1.5 W at the incident pump power of 30 W and at a repetition rate of 50 kHz, corresponding to the optical conversion efficiency of 5%. The shortest pulse width, the maximum pulse energy and the highest peak power were measured to be 5.8 ns, 46.7 μJ and 5.9 kW, respectively.     

13 W continuous-wave intracavity frequency-doubled Nd:YAP/LBO laser at 670.8 nm

Optical Review - We report on a high-power continuous-wave (CW) intracavity frequency-doubled laser at 670.8 nm, which is produced by the second-harmonic generation of a diode side-pumped...     

Continuous-wave intracavity frequency-doubled Nd:Yag-KTiOPO<Subscript>4</Subscript> red laser

Efficient and compact red laser output at 669 nm is generated by intracavity frequency doubling of a continuous-wave (CW) diode-pumped Nd:YAG laser at 1338 nm. With 16.9 W of diode pump power and the frequency-doubling crystal KTiOPO₄ (KTP), a maximum output power of 582 mW in the red spectral range at 669 nm has been achieved, corresponding to an optical-to-optical conversion efficiency of 3.4%; the output power stability over 4 h is better than 3.6%. To the best of our knowledge, this is first work on intracavity frequency doubling of a diode pumped Nd:YAG laser at 669 nm.     

Efficient intracavity frequency-doubled Nd:GdVO4-LBO red laser at 670.5 nm under direct 888 nm pumping

We report an efficient laser emission on the 1341 nm ⁴ F _3/2 to ⁴ I _13/2 transition in Nd:GdVO₄ under the pump with diode lasers at 888 nm. Continuous wave (CW) 6.58 W output power at 1341 nm is obtained under 18.3 W of incident pump power; the slope efficiency with respect to the incident pump power was 45.1%. Moreover, intracavity frequency doubling with LiB₃O₅ (LBO) nonlinear crystal yielded 1.77 W of red light at 670.5 nm.     

60 W yellow laser at 561 nm by intracavity frequency doubling of a diode-pumped Q-switched Nd:YAG laser

A high-power yellow laser was achieved by intracavity frequency doubling of a diode-pumped Nd:YAG rod laser. A solid etalon was inserted into the resonator to implement efficient operation of the low-gain single line at 1123 nm transition. By using a LBO crystal inside the cavity as the frequency doubler, the maximum output power of the 561 nm yellow laser was obtained to be as high as 60.3 W with a pulse repetition frequency of 6 kHz, corresponding to an optical-to-optical conversion efficiency of about 6.1%. The output power fluctuation of the yellow laser was measured to be better than 3% in half an hour.     

Compact diode-pumped Nd:YVO4 intracavity-doubled red laser at 671 nm

A design of diode-pumped high efficiency Nd:YVO₄/LBO laser with a compact linear cavity was reported. Employing a type-II noncritical phase-matched LBO crystal, we generated 520 mW of 671 nm in single transverse mode at 6 W of incident pump power, the optical conversion efficiency being 8.7%.     

Blue‐green light generation using high brilliance edge emitting diode lasers

A review about second harmonic generation using edge emitting diode lasers and nonlinear crystals to obtain laser radiation in the blue‐green spectral range is presented. Therefore, pump laser radiation with high brightness and narrow bandwidth is necessary. Thus, this review gives an overview of the advances made with distributed feedback and Bragg reflector lasers, tapered lasers and amplifiers as well as external cavity diode lasers and master oscillator power amplifier schemes to achieve high brilliance emission. Since periodically poled materials have enabled high second harmonic conversion efficiencies with low and moderate pump powers, the review is focused on frequency doubling using those materials. The most commonly used materials, their properties and limitations are discussed briefly. Single pass and resonant SHG setups with waveguide and bulk nonlinear crystals are discussed and an emphasis on building compact and integrated devices is made.     

An efficient and compact laser-diode end-pumped intracavity frequency-tripled Nd: YVO4 355 nm laser

By exploiting the intracavity frequency conversion configuration, a diode end-pumped acousto-optic (AO) Q-switched Nd:YVO₄ 355 nm laser was demonstrated in this paper. Two LBO crystals were inserted in the cavity to realize the frequency tripling operation, a cascade of the second harmonic generation (SHG) and sum frequency mixing (SFM). Under the absorbed pump power of 13 W, the maximum average output power at 355 nm was obtained to be 1.32 W at the repetition frequency of 17 kHz, with the optical-to-optical conversion efficiency of 10.2%. The corresponding pulse width was 10.2 ns, with the energy of a single pulse and corresponding peak power estimated to be 77.6 μJ and 7.61 kW, respectively.     

Compact efficient 1.5 W continuous wave Nd:YVO4/LBO blue laser at 457 nm

A compact folded three-mirror cavity with length of 100 mm is optimized to obtain high efficient 457 nm laser. When the incident pump power into Nd:YVO₄ is 16.3 W, as high as 1.52 W continuous wave 457 nm blue laser is achieved by LBO intracavity frequency doubled. The optical-to-optical conversion efficiency is greater than 9.3%.     

Efficient diode-pumped passively Q-switched laser with Nd:YAG/Cr:YAG composite crystal

Diffusion bonded Nd:YAG/Cr:YAG composite laser crystal has been employed to perform a compact diode-pumped passively Q-switched laser. At the incident pump power of 3.3 W and pulse repetition rate of 16.3 kHz, the maximum average output of 592 mW has been obtained, corresponding to an optical-to-optical conversion efficiency of 18%. Stable passively Q-switched operation with peak power of 6.5 kW and pulse duration of 6 ns was also achieved. It has been experimentally revealed that Nd:host/Cr:YAG composite structure is a promising material for compact cost-effective Q-switched laser sources with high-peak power and short pulse duration. In addition, thermal lens effect (TLE) in the active medium and its impact on the Q-switched laser performance have been analyzed.     

窄脉宽LD泵浦全固态绿光激光器的实验研究

研究了绿光平均功率达84W的高稳定声光调Q全固态激光器。通过理论分析和试验研究,针对KTP热效应以及Nd∶YAG棒的热致双折射效应,设计并优化了谐振腔来压窄脉宽。采用35个20W的高功率LD侧面抽运Nd∶YAG棒和Ⅱ类相位匹配KTP晶体(24℃时相位匹配角为Φ=23.6°,θ=90°,尺寸为7mm×7mm×7mm),采用双声光Q开关,高效平凹结构,实现了高功率内腔倍频激光器的稳定运转;在抽运电流25A时,获得了重复频率为10kHz,脉冲宽度优于45ns,输出功率为84W的高功率、高重频、窄脉宽绿光(532nm)输出,光_光转换效率为14.3%,不稳定度为±3%。