Junichiro Kojou

Cr4+-Doped Y3Al5O12 as a Saturable Absorber for a Q-Switched and Mode-Locked 639-nm Pr3+-Doped LiYF4 Laser

We experimentally prove that a Cr4+-doped Y3Al5O12 (YAG) crystal exhibits saturable absorption in visible wavelengths at 639, 607, and 521 nm. From z-scan measurements, the saturation energies measured using laser pulse widths of 25 and 66 ns at 639 nm are estimated to ~11.5 and 21.2 mJ/cm2, respectively. Therefore, the absorption response time will be shorter than these pulse widths. Using the Cr4+:YAG saturable absorber, we demonstrate for the first time, to the best of our knowledge, the passive Q-switched and the Q-switched mode-lock Pr3+-doped LiYF4 (YLF) lasers at 639 nm pumped by an InGaN diode laser.

Intracavity second-harmonic generation at 320 nm of an actively Q-switched Pr: LiYF4 laser

We demonstrate pulse laser operation of a Pr:LiYF(4) laser pumped by InGaN laser diodes (444 nm) using an acousto-optic modulator. We obtained a maximum laser peak power of 167 W (4 μJ/pulse) with a pulse width of 24 ns at an 11 kHz repetition rate for a 63 nm wavelength. Employing an 8 mm long lithium triborate nonlinear crystal in the laser cavity, we obtained a maximum peak power of 55 W (2.7 μJ/pulse) at 320 nm, which corresponds to a conversion efficiency of 69% with respect to the fundamental laser energy. The UV laser pulse width was 36 ns.

InGaN diode pumped actively Q-switched intracavity frequency doubling Pr:LiYF 4 261 nm laser

We demonstrate actively Q-switched deep ultraviolet laser operation at 261 and 320 nm by intracavity frequency doubling of an InGaN laser diode-pumped Pr:LiYF₄ laser. We obtain a maximum peak power of 61.6 W (8.7 μJ/pulse at 7.7 kHz) and 594 W (19.0 μJ/pulse at 7.7 kHz) with a pulse width of 142 and 35 ns at 261 and 320 nm, respectively. The conversion efficiency from the fundamental laser energy at 639 nm to the second-harmonic generation is 88%. Good agreement is obtained with prediction by a rate equation model.

Intracavity Second Harmonic Generation of Passively Q-switch Mode Locked Pr 3+ -doped Fluoride Lasers using Cr 4+ :YAG Saturable Absorber

We demonstrate passive Q-switching and Q-switched mode locking of Pr³⁺-doped fluoride lasers in the visible region using a Cr⁴⁺:YAG saturable absorber. Intracavity frequency doubling generates deep ultra-violet from the Pr³⁺:YLF laser.

Q-switched and mode-locked 639-nm PrrYLF laser with Cr:YAG saturable absorber

Z-scan measurements were performed to examine the saturable absorption of a Cr⁴⁺:YAG crystal at 639, 607, and 521 nm using actively Q-switched Pr³⁺:YLF laser pulses.

Intracavity frequency doubling at 261nm of an actively Q-switched Pr:LiYF 4 laser

We report actively Q-switched deep ultra-violet laser operation at 261nm by intracacity frequency doubling of InGaN laser diode pumped Pr:LiFY4 laser. We obtained a maximum peak power of 61.6W(8.7 μJ/pulse) at 261 nm.

Q-switch mode-locking of Pr 3+ -doped YLF laser at 639 nm with a Cr 4+ -doped YAG saturable absorber

We experimentally prove that a Cr⁴⁺:YAG crystal exhibits saturable absorption in visible wavelengths. We demonstrate the first passively Q-switch mode-locked Pr³⁺:YLF laser with a Cr⁴⁺:YAG at 639 nm pumped by InGaN diode lasers.

Wavelength tunable Q-switch laser in visible region with Pr 3+ -doped fluoride-glass fiber pumped by GaN diode lasers

Q-switching of wavelength tunable Pr3+-doped fluoride-glass fiber laser pumped by high-power GaN laser diodes is demonstrated. Highest laser peak power of 102 W with 20 ns pulsewidth is obtained for 607 nm at 8.3 kHz.

High-power GaN diode pumped Q-switch Pr 3+ -doped LiYF 4 laser

A Q-switch Pr:LiYF4 laser at 639 nm pumped by a high-power GaN laser diode is demonstrated. The highest laser peak power of 4.8 W with a pulsewidth of 270 ns is obtained at 7.7 kHz.