Semiconductor lasers are used for which set of applications?

• A. Solar energy conversion
• B. Welding
• C. Cooking
• D. Ranging, infrared illumination, intrusion alarms, fiber-optic communications, and optical scanning

Answer: (D)

Semiconductor lasers excel as compact, efficient, coherent light sources with a narrow spectral line, good directionality, and fast modulation. Those qualities make them ideal for tasks that rely on precise, controllable light beams rather than broad, noncoherent sources. The set that fits this best includes ranging (distance measurement with a narrow, steerable beam), infrared illumination (providing IR light for night-time sensing), intrusion alarms (active sensing along a beam path), fiber-optic communications (light source for high-speed data transmission through fibers), and optical scanning (driving scanners in barcode readers, printers, and similar devices).

Solar energy conversion, welding, and cooking involve applications where either the light is used to generate electricity or much higher power, different wavelengths, or different beam characteristics are required, so semiconductor lasers aren’t the typical choice for those tasks.