Using Gas Laser Mirrors in a Solid State Laser?
While this may be possible in some cases, there are a number of factors to consider and it is probably not recommended: • Reflectivity: Since they aren’t designed for the solid state laser’s wavelength, the reflectivity will likely not be optimal. HeNe mirrors may have too high a reflectivity at the ruby’s 694 nm but too low at YAG’s 1,064 nm. It would have to be measured. Also, the Anti-Reflection (AR) coating will not be optimized for the new wavelength. CAUTION: If the resonator Q is too high due to high reflectivity of both the HR and OC, the peak power could be great enough to damage the rod, optics, and your disposition. 🙂 • Curvature: Many HeNe and other similar mirrors are not planar. This is undesirable in a solid state laser because it results in a ‘hot spots’ – a region of concentrated energy where the circulating light flux is higher. This reduces efficiency and may actually damage the rod in extreme cases. • Diameter: Lasers salvaged from HeNe or argon ion laser tubes are
