Single Frequency Oscilation in a Coupled Cavity ND:GYLF Laser by Interferometric Control of the Cavity’s Length

Single frequency stabilization in solid-state laser resonators is essential for many applications as for example LIDAR or high-resolution spectroscopy. Nowadays there exists a whole new branch of lasers that are very well suited for these diverse applications, which are based on laser crystals optically pumped by high power semi-conductor diodes. These lasers are very compact and have only minimal demands on the local infrastructure. We use a new technique, based on the combination of active and passive stabilization techniques, which allows us to achieve a greatly enhanced frequency selectivity. Using a high power diode, operating at 792 nm, we pump longitudinally a Nd:GYLF laser crystal. This new crystal can be made very small without reducing its efficiency and therefore the overall cavity length is also very small (less than one cm). With an electro-strictive actuator we stabilize as few as possible laser ressonator modes. This is done by detuning the spectral hole burning modes (SHB) of the laser crystal from the cavity modes through nanometric adjustment of the cavity length and crystal position. Finally the effective reflectivity of the coupled cavity is adjusted to give high loss for all remaining frequencies except one. This is to our knowledge the first report of Nd:YGLF laser operation and single-frequency tuning. A estabilização em freqüência única em lasers de estado sólido e ́ essencial para muitas aplicações, como por exemplo, LIDAR e espectroscopia de alta resolução. Atualmente existe toda uma nova área de lasers que sã