Optical superradiance in a Pr3+:LaF3 crystal

Optical superradiance was experimentally obtained for the first time on the ³P₀ — ³H₄(0) transition in a Van Vleck paramagnet — a Pr³⁺:LaF₃ crystal. Superradiance at a wavelength of 477.7 nm was emitted by a sample 8 mm long, with resonant absorption coefficient α = 4.7 cm^–1, excited by 10-ns laser pulses at a temperature of 2.2 K.