A laser with a light frequency transducer (typically of the frequency doubler type) within a lser cavity. The cavity is mirrored to reflect light at the lased frequency and to transmit light from the cavity at the transduced frequency. The laser is provided with a convex lens at its end adjacent the frequency transducer. Likewise, the cavity mirror adjacent the frequency transducer is provided with a concave reflecting surface. The convex lens in cooperation with the concave cavity mirror provides a necessary light pupil through the light frequency transducer for efficient frequency change and a collimated light path through the laser for efficient light emission. When utilized with a YAG laser and a silicon filter disposable into and out of the optic axis of the laser, a barium-sodium-niobate light frequency transducer can be heat tuned to provide a 6,600 angstrom lasing mode useful for repair of retinal detachment and a 5,320 angstrom mode useful for treating the retinal blood vessels of diabetics.