Low‐Power Laser Applications

This chapter covers applications that require low laser power, typically well under a watt. An important emerging new market for lasers is laser radars or lidars for autonomous cars. The principle of lidar is the same as microwave radar. Some major advantages and some important limitations of lasers are listed in a table. Low‐power lasers are widely used to read printed symbols. The laser spot scans across a surface, and a detector measures changes in the reflected light as the beam moves. The biggest single application of lasers in terms of the number of lasers sold has been for playing and/or recording information on optical disks. Lasers have proved invaluable for many types of measurements. Laser instruments have long been used in surveying and construction alignment. Laser light shows emerged after bright argon and krypton lasers became available. Argon provides the green and blue beams and krypton emits in the red.