Tunable UV source based on an LED-pumped cavity-dumped Cr:LiSAF laser

Abstract

We developed a light-emitting diode (LED)-pumped Cr:LiSAF laser operating in Qswitched and cavity-dumped regimes. The laser produces 1.1 mJ pulses with a pulse duration of 8.5 ns at a repetition rate of 10 Hz on a broad spectrum centered at 840 nm with a full width at half maximum of 23 nm. After frequency tripling in two cascaded LBO crystals, we obtained 7 ns pulses with an energy of 13 µJ at 280 nm and with a spectral width of 0.5 nm, limited by the spectral acceptance of the phase matching process. By rotating both LBO crystals, UV emission is tuned from 276 nm to 284 nm taking advantage of the broad infrared spectrum of the Cr:LiSAF laser.

Exploring light-emitting diode pumped luminescent concentrators in solid-state laser applications

“…After this first demonstration, Pichon et al proposed to implement this new laser technology in more complex laser systems. They developed a tunable source in the UV based on a cavity dumped LED-LCpumped Cr:LiSAF [58]. Next, they demonstrated a LED-LC-pumped femtosecond regenerative amplifier [59] and a first Master Oscillator Power Amplifier (MOPA) based on two LED-pumped Cr:LiSAF [60].…”

Cavity-dumped nanosecond Cr:LiSAF laser in the 985–1030 nm region for versatile seeding of Yb-based amplifiers

“…As an example, a 0.5 W diode-pumped Cr:LiSAF laser which produce around 2 nJ of pulse energies in typical mode-locked operation (200 mW at 100 MHz), could be cavity-dumped to produce pulse energies above 100 nJ level (50 times scaling in output pulse energies at the expense of reduced repetition rate: 10-1000 kHz) [46]. Note that in this cavity-dumping approach, the energy is stored in the intracavity field rather than in the laser crystal [47], and the requirement for efficient storage is to have an ultra-low loss resonator, and one is not limited by the storage lifetime of the laser crystal. As a drawback, Cr:LiSAF suffer from Auger upconversion [48], excited-state absorption [49], temperature quenching of fluorescence lifetime [50], and have a relatively low thermal conductivity (1.8 W/Km), which makes it more susceptible to thermal effects compared to Ti:Sapphire.…”

“…In this work, we have investigated the potential of Cr:LiSAF laser as a tunable nanosecond seed source for Ybbased amplifiers, especially focusing our attention on cryogenic Yb:YLF systems. Similar to Ti:Sapphire, the 1000 nm region is at the edge of the tuning range for Cr:LiSAF (ECS is five-fold smaller compared to the peak value); hence, typical approaches do not provide pulses with high peak power/ energy at this wavelength region [41,51] (except in lowrepetition-rate flashlamp/LED pumped systems [47,52,53]). To circumvent this limitation, as it was explored earlier [46], we have tried cavity-dumping approach to exploit the energy storage capability of Cr:LiSAF resonators to our advantage in scaling the peak powers.…”