Anti-resonant ring laser cavities

Abstract

Lasers are self-organising systems that will operate in whichever mode is favourable and minimises the required gain. Conventionally, to select a desired mode of operation techniques such as apertures or spectral filters are used to inhibit the modes not wanted, which inherently increase losses and are non-adaptive. A potentially more fruitful approach is to design cavities such that the required mode of operation is also favoured by the laser by design. This has been shown to be achievable by sharing a gain or other element between two laser cavities [1]. In this work we present results from a Nd:YVO 4 laser with the gain element inside an Anti-Resonant Ring (ARR), also known as a Sagnac interferometer [2]. ARRs have been used before as an adaptive mirror for a laser cavity, but not with the gain element inside the ring itself. This presents the possibility of sharing a single gain element between two independent laser cavities with perfect spatial overlap.