A slider configured for heat-assisted magnetic recording comprises an optical sensor coupled to first and second bond pads. The optical sensor comprises a bolometer and a reference sensor. The bolometer is situated at a location of the slider that receives at least some of the light and exposed to an ambient temperature at the slider. The bolometer produces a signal in response to a change in the ambient temperature and the change in output optical power. The reference sensor is situated at a location of the slider unexposed to the light and exposed to the ambient temperature. The reference sensor is coupled to the bolometer and configured to produce a signal in response to the change in the ambient temperature. The optical sensor is configured to generate a sensor signal indicative of changes in output optical power of a laser source without contribution due to ambient temperature changes.