Jing-Yuan Zhang

167.75-nm vacuum-ultraviolet ps laser by eighth-harmonic generation of a 1342-nm Nd:YVO4 amplifier in KBBF.

We demonstrate a ps 167.75-nm vacuum-ultraviolet (VUV) laser by cascaded second-harmonic generation (SHG). The VUV laser is produced by eighth-harmonic generation (EHG) of a mode-locked ps 1342-nm Nd:YVO4 amplifier through three stages cascaded SHG with two LiB3O5 crystals and one KBe2BO3F2 crystal, successively. The 167.75-nm laser provides up to 65-μW output power, and the corresponding photon flux and photon flux density are 5.5×10(13)u2009u2009s(-1) and 1.6×10(18)u2009u2009s(-1)·cm(-2), respectively.

High-power diode-side-pumped rod Tm:YAG laser at 2.07 μm

We report a high-power diode-laser (LD) side-pumped rod Tm:YAG laser of around 2 μm. The laser was water-cooled at 8°C and yielded a maximum output power of 267 W at 2.07 μm, which is the highest output power for an all solid-state cw 2.07 μm rod Tm:YAG laser reported as far as we know. The corresponding optical-optical conversion efficiency was 20.7%, and the slope efficiency was about 29.8%, respectively.

High-Efficiency 2-mJ 5-kHz Picosecond Green Laser Generation by Nd:YAG Innoslab Amplifier

A high-efficiency picosecond (ps) 532-nm green laser with high pulse energy and high peak power at 5-kHz repetition rate was demonstrated by second-harmonic generation (SHG) from a 1064-nm master oscillator power amplifier (MOPA). The MOPA was based on the Innoslab structure under diode directly pumping, producing 4.8-mJ, 25-ps fundamental laser at the repetition rate of 5 kHz after a three-stage Innoslab amplification system. With a pulse energy of 2.93 mJ in the fundamental and using a type I noncritically phase matched lithium triborate crystal, the pulse energy of SHG was up to 1.96 mJ per pulse with a pulse width of 18.9 ps, which corresponds to a peak power of 104 MW in the green and SH conversion efficiency as high as 67%. The SHG green beam quality factor was measured to be M2 = 1.75.

Experimental investigation and theoretical analysis of pulse repetition rate adjustable deep ultraviolet picosecond radiation by second harmonic generation in KBe2BO3F2

We reported on an experimental investigation and theoretical analysis of pulse repetition rate (PRR) adjustable deep ultraviolet (DUV) picosecond (ps) radiation by second harmonic generation (SHG) in KBe2BO3F2 (KBBF) crystal. Third harmonic radiation at 355 nm of a ps Nd:YVO4 laser output with PRR of 200 kHz–1 MHz was employed as the pump source. The dependence of the 177.3 nm output power on the 355 nm pump power was measured at different PRRs, and the maximum 177.3 nm average output power of 695 μW was obtained at the PRR of 200 kHz. The measured data agreed well with the results of the ps KBBF SHG theoretical simulations. Using simulations, the pulse width and the spectral bandwidth of the generated radiation at 177.3 nm were estimated to be 5.88 ps and 7.84 pm, respectively.

83 W yellow-green laser at 556 nm from frequency-doubling of a Q-Switched Nd:YAG laser at 1112 nm in LBO

We demonstrate a high power 556 nm yellow-green laser by intracavity frequency doubled of the diode-pumped 1112 nm Nd:YAG laser in a symmetrical L-shaped flat-flat cavity. The coatings of the resonator mirrors were carefully designed to achieve efficient operation of fundamental wavelength of the laser at 1112 nm. By using a type-II phase matching LBO nonlinear crystal as the frequency-doubler, the maximum output power of the 556 nm laser was measured to be as high as 83 W with a pulse repetition frequency (PRF) of 10 kHz under incident pump power of 1150 W, corresponding to an optical-to-optical conversion efficiency of about 7.2%. The fluctuation of output power was less than 2% over 30 min.

Millijoule-level picosecond mid-infrared optical parametric amplifier based on MgO-doped periodically poled lithium niobate.

A millijoule-level high pulse energy picosecond (ps) mid-infrared (MIR) optical parametric amplifier (OPA) at 3.9xa0μm based on large-aperture MgO-doped periodically poled lithium niobate (MgO:PPLN) crystal was demonstrated for the first time, to the best of our knowledge. The MIR OPA was pumped by a 30xa0ps 1064xa0nm Nd:YAG laser at 10xa0Hz and injected by an energy-adjustable near-infrared seed based on a barium boron oxide (BBO) optical parametric generator/optical parametric amplifier (OPG/OPA) with double-pass geometry. Output energy of 1.14xa0mJ at 3.9xa0μm has been obtained at pump energy of 15.2xa0mJ. Furthermore, the performance of MIR OPG in MgO:PPLN was also investigated for comparing with the seeded OPA.

A picosecond widely tunable deep-ultraviolet laser for angle-resolved photoemission spectroscopy

We develop a picosecond widely tunable laser in a deep-ultraviolet region from 175 nm to 210 nm, generated by two stages of frequency doubling of a 80-MHz mode-locked picosecond Ti:sapphire laser. A β-BaB2O4 walk-off compensation configuration and a KBe2BO3F2 prism-coupled device are adopted for the generation of second harmonic and fourth harmonics, respectively. The highest power is 3.72 mW at 193 nm, and the fluctuation at 2.85 mW in 130 min is less than ±2%.

High-Power High-Beam-Quality 330-nm Laser From a Frequency-Quadrupled Nd:YAG Laser

We demonstrate a high-power high-beam-quality ultraviolet (UV) laser at 330 nm based on fourth-harmonic generation (FHG) of a diode-side-pumped 1319-nm Nd:YAG laser. A 23.2-W Q-switched Nd:YAG laser at 1319 nm with beam quality factor M2 = 1.15 and optical to optical conversion efficiency of 6.5% was employed as the fundamental wave source. First, the output at 1319 nm was frequency doubled to 660 nm in an LiB3O5 (LBO) crystal with an average output power of 11.3 W. Then, it was frequency doubled again in another LBO crystal to obtain the FHG output at 330 nm. The maximum average output power at 330 nm was up to 7 W, and the beam quality factor M2 was measured to be 1.45. The conversion efficiency was 48.7% at the first second-harmonic generation (SHG) stage, and the conversion efficiency of the second SHG stage was 61.9%, corresponding to a total conversion efficiency from infrared to UV of 30.2%. To the best of our knowledge, this is the first 330-nm UV source generation from a diode-side-pumped frequency-quadrupled 1319-nm Nd:YAG laser.