Systems, apparatuses, and methods for multi-application optical sensing are provided. For example, an optical sensing apparatus can include a photodetector array, a first circuitry, and a second circuitry. The photodetector array includes a plurality of photodetectors, wherein a first subset of the plurality of photodetectors are configured as a first region for detecting a first optical signal, and a second subset of the plurality of photodetectors are configured as a second region for detecting a second optical signal. The first circuitry, coupled to the first region, is configured to perform a first function based on the first optical signal to output a first output result. The second circuitry, coupled to the second region, is configured to perform a second function based on the second optical signal to output a second output result.