Compact external cavity diode laser for quantum experiments

We present a compact and practical scheme of building a similar to 780 nm external cavity diode laser (ECDL) whose wavelength is mainly determined by an interference filter. The Lorentzian linewidth measured by the heterodyne beating between two identical lasers is 60 kHz, and the geometry size of the laser is only 71.5 mmx65 mmx40 mm. The linear cavity design is less sensitive to misalignment induced by mechanical and thermal disturbances, and in comparison to a common grating-based design, the sensitivity to vibration is substantially reduced. Due to its excellent performance, the laser design has already been applied to cold atom trapping experiments. This interference filter ECDL method can also be extended to other wavelengths and widen the application range of diode laser.