440 nm light generation by frequency tripling in germanosilicate glasses

Generation of 120 μW average power blue‐violet light at 440 nm through efficient frequency tripling of 1.319 μm Nd:YAG laser pulses in bulk GeO2‐SiO2 and Er3+‐doped GeO2‐SiO2 glasses is reported. Third‐harmonic signal light enhancement owing to two‐ and three‐photon resonant pumping of erbium ions in doped samples is also reported.