Optical systems that may, for example, be used in light ranging and detection (LiDAR) applications, for example in systems that implement combining laser pulse transmission in LiDAR and that include dual transmit and receive systems. Receiver components of a dual receiver system in LiDAR applications may include a medium range (50 meters or less) receiver optical system with a medium entrance pupil and small F-number and with a medium to wide field of view. The optical system may utilize optical filters, scanning mirrors, and a nominal one-dimensional SPAD (or SPADs) to increase the probability of positive photon events.