Tunable lasing due to the 4T2–4A2 electronic–vibrational transition in Cr3+ ions in BeAl6O10

Tunable radiation in the 0.79–0.87 μm range was obtained at room temperature in a new active medium BeAl₆O₁₀:Cr³⁺. The energy gap between the ²E and ⁴T₂ levels (~ 236 cm^–1) and the activation energy E_a ≈ 1667 cm^–1 were determined. Absorption, luminescence, and excitation spectra were determined and an investigation was made of the temperature dependence of the excited-state relaxation time of Cr³⁺ ions in BeAl₆O₁₀(τ_lum ≈ 13 X 10^–6 s at 300 K).