Alignment and Wavelength Selection In External Cavity Lasers

An external cavity laser comprising a laser diode, an intra-cavity wavelength conversion device, a wavelength selective element, and a multi-axial actuator, wherein:

• the laser diode, the intra-cavity wavelength conversion device, and the wavelength selective element are assembled as a folded external cavity semiconductor laser comprising an external cavity formed between highly reflective dielectric coatings at the rear facet of the laser diode and the output face of the wavelength conversion device;
• the wavelength selective element is coupled to the multi-axial actuator to enable adjustment of the position of the wavelength selective element relative to an optical axis Z of the external cavity laser by tilting and tipping the wavelength selective element about a wavelength insensitive axis X and a wavelength selective axis Y;
• the tilting of the wavelength selective element about its wavelength selective axis Y reflects a wavelength of interest along an optimum path in an XZ plane of the external laser cavity;
• the tipping of the wavelength selective element about its wavelength insensitive axis X reflects the wavelength of interest along an optimum path in a YZ plane of the external laser cavity;
• and
• the wavelength selective element is configured such that a given degree of tipping about the wavelength insensitive axis X yields an insignificant degree of wavelength tuning relative to that which would be generated under a corresponding degree of tilting about the wavelength selective axis Y.

A system for generating a projected laser image, the system comprising an external cavity laser, an optical intensity monitor, laser projection optics, and a controller, wherein:

• the controller, the external cavity laser, and the laser projection optics are configured to generate a projected laser image utilizing an output beam of the external cavity laser;
• the external cavity laser comprises a laser diode, an intra-cavity wavelength conversion device, and a wavelength selective element;
• the external cavity laser, the optical intensity monitor, and the controller form at least a portion of a feedback loop configured to control the wavelength selective element as a function of optical intensity;
• the system is programmed to adjust the position of the wavelength selective element relative to an optical axis Z of the external cavity laser to optimize the output intensity by tilting the wavelength selective element about its wavelength selective axis Y to reflect a wavelength of interest along an optimum path in an XZ plane of the external laser cavity and tipping the wavelength selective element about its wavelength insensitive axis X to reflect the wavelength of interest along an optimum path in a YZ plane of the external laser cavity;
• and
• the wavelength selective element is configured such that a given degree of tipping about the wavelength insensitive axis X yields an insignificant degree of wavelength tuning relative to that which would be generated under a corresponding degree of tilting about the wavelength selective axis Y.