Julien Didierjean

Wavelength selection, spatial filtering and polarization control of an Er:YAG laser cavity by resonant-grating mirror

Summary form only given. Er:YAG crystals are good candidates for eye-safe solid-state lasers with output pulses energy in the mJ range, which are required for applications in atmospheric propagation such as active imaging, lidar and wind mapping. Er:YAG crystals can emit at 1645 nm or 1617 nm. The laser emission of Er:YAG naturally occurs at 1645 nm and is unpolarized. In addition, the required high incident pump powers in quasi-three-levels laser such as Er:YAG could lead to a poor beam quality factor (M2) because of well-known thermal effects in rod lasers. Some applications may require emission at 1617 nm with a good M2 factor for long range sensing, as well as linearly polarized output beams for pollutant probing [1]. Therefore, a basic Er:YAG cavity could be provided with an intra-cavity etalon for wavelength selection [2], a reflective polarizer for polarization control, and a pinhole for spatial filtering. In this contribution, we report on a resonant-grating mirror (Fig. 1 left) which can be used to fullfil these three functions, hence simplifying the laser setup [3].

Amplification of a Passively Q-Switched Nd:YAG Microlaser in a Crystal Fiber

A passively Q-switched Nd:YAG microchip laser generating 18.6 µJ, 5.5 ns pulses with a repetition rate of 29 kHz was efficiently amplified by a diode-pumped Nd:YAG crystal fiber amplifier to obtain 250 µJ pulses.

Micro-Pulling Down Nd:YAG Single Crystal Fibers for High Power Linearly Polarized CW and Q-Switched Lasers

We achieved 16-W polarized and 20-W unpolarized cw power at 1064 nm for 120-W of pump power and 360 kW peak power in the Q-Switched regime with Nd:YAG single-crystal fibers grown by micro-pulling-down technique.

High power single crystal fiber amplifiers for linearly and cylindrically polarized picosecond lasers

We demonstrated a three-stage diode-pumped Yb:YAG single-crystal-fiber amplifier to generate femtosecond pulses at high average powers with linear or cylindrical (i.e. radial or azimuthal) polarization.

Diode-pumped 1617 nm Er:YAG laser with micro-pulling down single-crystal fibers

We demonstrated diode-pumped laser operation at 1617 nm with Er:YAG 60 mm long and 600 µm diameter single-crystal fibers. We obtained 5.5 W in cw and 0.5 mJ 30 ns pulses at 100 Hz in Q-switched operation.

High Power Nd:YAG Single Crystal Fiber Emitting at 946 nm and 938 nm

We demonstrated a 34 W output power cw Nd:YAG laser emitting at 946 nm with a 53% slope efficiency using single crystal fiber. 20 W were also obtained at 938 nm.

High-power diode-pumped Q-switched Er 3+ :YAG single-crystal fiber laser

We describe an efficient laser emission from a directly grown Er3+:YAG single-crystal fiber that is resonantly pumped using a continuous-wave (CW) laser diode at 1532 nm. In a longitudinal pumping, it emits 12.5 W at 1645 nm with a slope efficiency of 32%, which is the highest ever reported for a directly grown Er:YAG single-crystal fiber laser. Using an off-axis pumping scheme, CW output powers up to 7.3 W can be reached and in Q-switched operation, the laser produces 2 mJ pulses with a duration of 38 ns at the repetition rate of 1 kHz with an M2 factor below 1.8. To our knowledge this is the first directly grown Er3+:YAG single-crystal fiber Q-switched laser.

High-power diode-pumped Q-switched Er3+:YAG single-crystal fiber laser

We describe an efficient laser emission from a directly grown Er3+:YAG single-crystal fiber that is resonantly pumped using a continuous-wave (CW) laser diode at 1532 nm. In a longitudinal pumping, it emits 12.5 W at 1645 nm with a slope efficiency of 32%, which is the highest ever reported for a directly grown Er:YAG single-crystal fiber laser. Using an off-axis pumping scheme, CW output powers up to 7.3 W can be reached and in Q-switched operation, the laser produces 2 mJ pulses with a duration of 38 ns at the repetition rate of 1 kHz with an M2 factor below 1.8. To our knowledge this is the first directly grown Er3+:YAG single-crystal fiber Q-switched laser.

Simultaneous Measurement of Thermal Lens and Temperature Map in Ytterbium-Doped Fluoride Crystals

We report on the simultaneous characterization of temperature map and thermal lensing in Yb3+ :CaF2and Yb3+ :SrF2crystals under high-power pumping with/without laser operation. This in situ measurement would allow proper designs of high-power cavities.

High Power Diode Pumped Yb 3+ :CaGdAlO 4 Laser

We study the performance of Yb3+ :CaGdAlO4under 100W diode pumping with a standard laser design. We also investigate the laser properties of Yb3+ :CaGdAlO4for different doping in order to optimize the absorption and wavelength tunability.