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Transparent glass-ceramics containing γ-Ga 2 O 3 :Co 2+ nanosized (7-12 nm) crystals are synthesized in a lithium gallium silicate system. Their spectroscopic and nonlinear properties are studied. The absorption band related to the 4 A 2g ( 4 F) → 4 T 1g ( 4 F) transition of Co 2+ ions in tetrahedral sites for these glass-ceramics is red-shifted up to ~1.8 μm. The absorption saturation fluence is determined to be ~0.8 J cm −2 . The developed glass-ceramics are used for passive Q-switching of diode-pumped Er,Yb:glass laser delivering 1.75 mJ 25 ns-long pulses at 1540 nm.

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A compact Raman laser gas spectrometer is developed. It comprises a high-power green laser at 532.123 nm as an excitation source and a specially designed gas cell with an internal volume of less than 0.6 cm3 that can withstand gas pressures up to 100 atm. The resolution of the spectrometer is ~1 cm−1. The Raman spectra of chemically pure isotopically enriched carbon dioxide (12CO2, 13CO2) and methane (12CH4, 13CH4) gases are studied. The expected limit of detection (LOD) is less than 100 ppm for the isotopologues of CO2 and less than 25 ppm for those of CH4 (at a gas pressure of 50 atm.), making the developed spectrometer promising for studying the sources of emissions of greenhouse gases by resolving their isotopologue composition. We also show the suitability of the spectrometer for Raman spectroscopy of human exhalation.