Read this: Infrared is used in night vision equipment when there is insufficient visible light to see. Night vision devices operate through a process involving the conversion of ambient light photons into electrons that are then amplified by a chemical and electrical process and then converted back into visible light. Infrared light sources can be used to augment the available ambient light for conversion by night vision devices, increasing in-the-dark visibility without actually using a visible light source.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): What do night vision devices convert ambient light photons into?
electrons