Spectrally Pure Eye-Safe Laser (SPESL)

To help with the detection of carbon dioxide, methane, and certain gaseous pollutants, NIST is seeking narrow linewidth, tunable and band-selectable, diode-pumped solid-state lasers in the wavelength region between 1550 nm and 1650 nm. Luminit proposes to develop the Spectrally Pure Eye-Safe Laser (SPESL). The SPESL is an Er:YAG laser, side pumped by semiconductor lasers in the erbium absorption band near 1475 nm, with an intracavity etalon and a switchable spectral filter. The etalon will reduce the laser linewidth to <50 MHz because, unlike traditional Q-switched short pulse lasers, the cavity-dumped SPESL circulates the photon flux through the etalon hundreds of times before sending it out. Cavity dumping also ensures constant pulse energy over a wide range of repetition rates, as low as 100 Hz and as high as 20 kHz (previous work indicates 100 kHz is achievable). The simple, automated system design ensure environmental ruggedness and ease of use.