Design of a Littrow-type diode laser with independent control of cavity length and grating rotation

We present a novel, to the best of our knowledge, extended-cavity diode laser based on a modified Littrow configuration. The coarse wavelength adjustment via the rotation of a diffraction grating is decoupled from the fine tuning of the external cavity modes by positioning a piezo transducer behind the diode laser, making the laser robust against misalignment and hysteresis even with long external cavities. Two laser prototypes with external cavities of different lengths were tested with a 780 nm laser diode, and locked to an atomic reference. We observed a mode-hop-free frequency tunability broader than the free spectral range of the external cavity upon changes in its length. The design is well suited to atomic and molecular experiments demanding a high level of stability over time. (C) 2021 Optical Society of America

Automated summary

A novel extended-cavity diode laser based on a modified Littrow configuration is presented, showing robustness against misalignment and hysteresis. Laser prototypes with different external cavity lengths were tested, exhibiting mode-hop-free frequency tunability upon changes in cavity length. This design is well suited for atomic and molecular experiments requiring long-term stability.