High power 7-GHz bandwidth external-cavity diode laser array and its use in optically pumping singlet delta oxygen

Using a 14-mm thick volume Bragg grating, spectral bandwidth of a cw-operated diode laser array is narrowed to 7 GHz (FWHM). Total output power reaches 13.5 W cw, of which 86% is in the 7-GHz band. With such a narrow bandwidth, it is possible to temperature tune laser frequency across O2 X3∏ → b1Σ+ absorption line at 763.8 nm, efficiently generating O2(1∆) molecules.