Dual-wavelength injection-seeded Q-switched Ho:YLF laser for CO₂ differential absorption lidar application

A dual-wavelength injection-seeded Q-switched Ho:YLF laser for CO2 differential absorption lidar pumped by the thulium-doped fiber laser was demonstrated. The single-frequency Ho:YLF seed laser was achieved by a pair of highly anti-misalignment corner cubes. The wavelength of an online seed laser was corrected to the P12 CO2 absorption line at 2064.414 nm by using a CO2 absorption cell. At the pulse repetition frequency of 100 Hz, the single-frequency pulsed energy was 16.1 mJ with the pulse width of 221.3 ns after a single-pass amplifier. The full width at half-maximum of a single-frequency pulsed spectrum was about 3.87 MHz, and the fluctuation of center frequency was 2.8 MHz in 30 min.