An apparatus in the field of optics technology, can include a reflector, a reflector substrate, and an extinction component. The reflector can be mounted on the reflector substrate. The extinction component can be arranged on a front surface of the reflector substrate. The reflector can be configured to reflect incident light signals. The extinction component can be configured to reduce the scattered light produced by the incident light signal on the reflector substrate. An optical scanning device (for example, lidar) having such features may greatly reduce the scattered light inside the lidar, reduce the detection blind area caused by the stray light, and greatly improve the receiving and detecting capabilities of the lidar.