Spectroscopic use of a novel blue diode laser in a wavelength region around 450 nm

This paper reports on the first spectroscopic application of a novel type of GaN blue diode laser emitting around 450 nm, which has recently become available. The diode was characterised and then implemented in an extended cavity, to achieve mode-hop free tuning over a frequency range exceeding 105 GHz. The spectroscopic utility of the device was demonstrated by probing the 5(2)P(3/2) to 6(2)S(1/2) transition of atomic indium seeded to an atmospheric pressure flame. Single scans over the pressure broadened hyperfine structure were recorded with high signal-to-noise ratios and profiles of the indium LIF distribution through the flame were acquired, at a high spatial resolution. Potential applications of diodes emitting in this spectral region range from industrial sensing to atomic cooling experiments.