ACCURATE FREQUENCY-TUNING MECHANISM FROM A WEDGE PRISM IN A SINGLE-MODE TUNABLE LASER

We present a new, accurate frequency-tuning mechanism in a grazing-inc idence cavity for single-longitudinal-mode oscillation in a tunable la ser. A wedge prism with a small apex angle is inserted between the tun ing mirror and the grating for accurate frequency tuning. In this conf iguration, the laser frequency can be tuned precisely by rotation of t he wedge instead of the tuning mirror. This fine-tuning mechanism offe rs the ability to tune the frequency over more than 400 GHz without mo de hop and with a tuning accuracy that is 2 orders of magnitude larger than that of conventional tuning methods.