Mode Selection in Resonators With Conical Reflectors

The characteristics of laser oscillators can be modified toward specific requirements by inserting suitable optical elements in the resonator. We show that replacing one of the resonator mirrors by a conically shaped reflector can lead to a significant increase in the volume of the fundamental mode resulting in improved power efficiency. Alternatively, the first azimuth mode, which is important for various applications, such as high-resolution microscopy, can be selected by inverting the reflector head angle.