ABSTRACT
Section 4.2 brie¦y describes some nonlaser light sources: highpressure arc lamps, low-pressure vapor lamps, incandescent lamps, and light-emitting diodes (LEDs). Greater emphasis is placed on laser light sources as these play a more signi›cant role in state-of-art biomedical optics techniques. Some basic properties that make laser radiation particularly useful in biomedical optics applications are discussed. ™e fundamental components of a laser are explained in the terms of their function during laser operation. As much progress in biomedical optics has been enabled by nanosecond-to femtosecond-duration laser pulses, some basic concepts of pulsed laser operation are also introduced. Finally, four types of lasers-gas, solid-state, dye, and
semiconductor-are described and dižerentiated. Some speci›c examples of each type are also enumerated in the context of relevant biomedical applications.
