Which substance is primarily used in LIDAR systems to facilitate light passage?

The substance primarily used in LIDAR systems to facilitate light passage is Gallium-Arsenide Diodes. These diodes are significant in LIDAR because they are efficient in emitting infrared light, which is critical for the system's functioning. LIDAR systems rely on the transmission of laser light pulses to measure distances by calculating the time it takes for the light to bounce back after hitting an object.

Gallium-Arsenide is highly advantageous in this application because it possesses a wide bandgap, which allows for high efficiency in converting electrical energy into laser light. This makes them particularly effective for LIDAR applications where the quality and speed of light emission directly impact the system’s performance.

The other substances listed, such as Silicon and Germanium, are typically used in different contexts within semiconductor technology, but they do not provide the same level of efficiency or effectiveness in light emission for LIDAR systems as Gallium-Arsenide. Indium Phosphide is also effective in other types of optoelectronic devices but is less common than Gallium-Arsenide Diodes in typical LIDAR systems. Thus, Gallium-Arsenide Diodes emerge as the preferred choice for enabling effective light passage in LIDAR applications.