ABSTRACT
This chapter discusses the principles and techniques involved in the measurement of laser power, spectrum, and wavelength. The three basic components of a laser power meter are a photodetector, an electronic conditioner, and a display device. Three photodetectors are commonly used in laser power meters. They are thermopiles, photodiodes, and pyroelectric probes. Silicon and germanium photodiodes are widely used as photodetectors. A pyroelectric probe uses a ferroelectric material that is electrically polarized at a certain temperature. Integration spheres are designed to collect the power of highly divergent laser beams, such as semiconductor laser beams, since these beams can overfill the input window of a photodetector and cause considerable measurement error. A diffraction grating can spatially disperse a polychromatic laser beam into its monochromatic components and is the most widely used optical device for analyzing optical spectrum covering a relatively wide range. Monochromators are instruments widely used for optical spectrum analysis.
