Shortwave infrared (SWIR) imagers generally use reflected light to image a scene. In many instances there are no natural sources of illumination available, i.e. caves, tunnels, basements, etc. In these situations, covert active illumination sources that are not detectable to the human eye, night vision goggles, or silicon cameras are needed to illuminate the area without detection from those common imaging technologies. Shortwave infrared cameras from SUI can image these covert illumination sources; the camera's high signal-to-noise ratio is an added benefit. This fundamental ability of InGaAs cameras to see these SWIR lights is an important military capability.

Covert illumination (1550 nm) in complete darkness with a SWIR camera.	While the person is quite visible due to its thermal signature, the MWIR thermal imager cannot detect other objects because they are all at room temperature.

This advantage is critical on the battlefield, as it allows the war fighter to acquire important information without giving away the soldier's location. Covert illumination paired with a shortwave infrared camera will provide the user with mission-critical information, while protecting him or her in the field. Covert illumination and SWIR detectors can protect valuable tanks or unmanned ground vehicles from potential threats. For example, an active illumination system could allow troops to extend a camera and illuminator around corners in low light levels, in dark patches of underbrush, or while moving into a dark cave. The camera and illuminator can also be integrated into larger systems for active night time surveillance.