Application of 940 nm high-power DFB lasers for line-broadening measurements at normal pressure using a robust and compact setup

High-power distributed-feedback (DFB) lasers for the wavelength range near 940 nm (i.e. about 10,600 cm⁻¹) were used for line-broadening measurements of individual rotational-vibrational absorption lines of water vapour at atmospheric pressure using a minimalist set-up. The laser has a maximum output power larger than 500 mW. Over the whole power range from threshold to maximum power, it operates in single mode operation with a tuning range of 4.7 nm, i.e. 50 cm⁻¹, at 20°C. With an emission line-width ≤2 MHz (0.66×10⁻⁴ cm⁻¹), the device is well suited for high-resolution spectroscopy.