The present application relates to the technical field of
optical reflection cavities. Provided are an
optical reflection cavity, an optical multi-pass
cell system, and an optical
resonant cavity system. In the
optical reflection cavity provided in the embodiments of the present application, a first sub-
plane mirror is introduced into a plano-concave cavity, the first sub-
plane mirror is disposed in an
edge region of a main
plane mirror in a y-axis direction and is inclined relative to the main plane mirror in the y-axis direction, and the length of the first sub-plane mirror in an x-axis direction is at least one times the width of a trajectory of a
light beam on the main plane mirror in the x-axis direction, so that the
light beam can be reflected by the first sub-plane mirror at least once, and the translation direction of the trajectory is continuously changed after the
light beam is reflected by the first sub-plane mirror, so as to increase the number of reflections of the light beam within a limited volume, thereby increasing an
optical path length and the distribution density of reflected light spots. Compared with a Herriot
cell and a
White cell, more reflections, a larger optical-path-length-to-volume ratio and a higher distribution density of the light spots can be achieved.