Study of wavelength-switchable watt-level blue external cavity diode laser for NO2 S-DIAL

A 2.3 W wavelength-switchable blue external cavity diode laser (ECDL) was studied. The laser was built on Littrow configuration and a piezoelectric ceramic transducer (PZT) driver was employed to change the Littrow angle for wavelength tuning. Its emitting wavelength can be switched between 447.46 nm and 448.10 nm which are the required wavelengths for NO2 differential absorption lidar application. The measured spectral linewidth of the proposed ECDL was 0.08 nm. The main peak was at least 35 dB stronger than its adjacent freely running emission peak and background amplified spontaneous emission (ASE). The wavelength switching dynamics were inspected and shows good repeatability at frequencies of 16.7 Hz and 50 Hz.