Systems and methods for a multi-band position sensor and a multi-band optical detector are disclosed. This system comprises a dual-axis, lateral-effect position sensor for locating spots of light that has energy in two wavelength bands. This sensor senses the time-varying intensities of the light in each of the two wavelength bands. This sensor also provides the location of the spot of light on the light-detecting plane of the sensor. Examples are provided for light of two mid-wave infrared (MWIR) wavelength bands or of a short-wave infrared (SWIR) and a MWIR band. This sensor approach, could be applied to detect light of other wavelength bands, such as a combination of a MWIR and a long-wave infrared (LWIR) band. This concept is extended to an array of detectors for multi-band optical detection and multi-source location and tracking. Monolithic chip level fabrication of the multi-band detectors is also discussed.