Analysis of no mode-hop tuning of mirror-grating external-cavity diode laser

The simplicity of structure and the no mode-hop tuning characteristic are of crucial importance for external-cavity diode laser applied in the field of experiment and engineering. A new and enhanced structure for mirror-grating Littrow-type external-cavity diode laser (ECDL) is proposed in this article. On the basis of this external cavity diode laser, a large mode-hop-free tuning range can be obtained and the direction of the output beam remains almost unchanged when the laser is tuned. We can tune the laser over a continuous range reaches 4.34 nm and the lateral displacement of output beam is only 0.033 mm at 805 nm when the initial length of external cavity is 12.82 mm.