Analysis of optical resonant cavity composed of nonparallel reflectors

We propose and numerically investigate a novel optical resonant cavity composed of nonparallel reflectors. The top reflector employs a ridge-shaped structure and consists of two flat mirrors, which are positioned symmetrically with the same inclined angle, it extends the interaction length between the reflectors and optical field. The total-energy density and optical field distribution are analyzed by means of the finite element method. One of the most important features of the cavity is that light beams can be confined in a smaller region drastically and the geometric loss of the cavity is reduced. Results indicate that, compared with the parallel F–P cavity with the same height, width, and material, this optical resonant cavity is characteristic of smaller linewidth, higher quality factor, and smaller mode volume, which can be useful for lasers, photodetectors, and displacement sensing.