We report on the fabrication and characterization of Er:YGG films suitable for waveguide amplifiers that could in principle be used in integrated path differential absorption lidar systems. Presented is our fabrication technique, comprising pulsedlaser- deposition growth of ~10 μm-thick crystalline films, their channeling via ultraprecision ductile dicing with a diamond-blade, producing optical quality facets and sidewalls, and amplifier performance. Net gain at 1572 nm and 1651 nm is obtained for the first time in Er-doped YGG waveguide amplifiers. Additionally, in a channel waveguide a maximum internal gain of 3.5 dB/cm at the 1533nm peak was realized. Recent crystal film quality improvements promise further performance enhancements needed for the intended application for high-peak power sources in the 1.6-μm spectral region targeting Earth observation systems for monitoring greenhouse gases.
Semiconductor nanostructures (multiple quantum wells type) design and manufacturing are developed for ternary and quaternary A<sub>3</sub>B<sub>5</sub> compounds. Characterization of SA by subpicosecond resolution pump-probe technique
was made for SA samples for Yb<sup>3+</sup>:KY(WO<sub>4</sub>)<sub>2</sub> and Nd<sup>3+</sup>:KGd(WO<sub>4</sub>)<sub>2</sub> lasers. Recovery kinetics contains the
"fast" (hundreds fs) and "slow" (hundreds ps) parts. Method of recovery time shortening based on ultra-violet
laser irradiation of SA was investigated; it showed the possibility to reduce the "slow" relaxation time by an
order of magnitude. Another approach based on application of nanostructured barriers between quantum wells
proved also quite suitable for recovery time shortening. A special method of a reflecting interferometer for
complete amplitude and phase characterization of laser mirrors was developed and tested. SA mirrors operating
in Yb<sup>3+</sup>:KY(WO<sub>4</sub>)<sub>2</sub> and Nd<sup>3+</sup>:KGd(WO<sub>4</sub>)<sub>2</sub> lasers gave promising results for peak power and pulse duration.