An external cavity laser system with narrow linewidth

This invention relates to the system design and wavelength tuning mechanism of an external cavity diode laser with narrow linewidth. The characteristic of the device on system design is to use a two-axis adjusting mount as the main structure of the laser system. There are two precision adjustable screws on this two-axis adjusting mount for optimizing the diffracted beam generated by the volume holographic grating (VHG). The diffracted beam can be feed back to the laser diode on the right hand side of the laser system. The characteristic of the device on wavelength tuning mechanism is to use a metal flexure applied to the laser system. There is a VHG attached onto the metal flexure which will diffract the laser beam and feed it back to the laser diode (fixed end). The rest of the laser power will penetrate through the VHG and become the output beam. Besides, there is also a piezoelectric transducer (PZT) inside the laser system and it can be activated by applying the electrical voltage. The PZT deflects toward