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SPIE Press is the largest independent publisher of optics and photonics books - access our growing scientific eBook collection ranging from monographs, reference works, field guides, and tutorial texts.

SPIE Press is the largest independent publisher of optics and photonics books - access our growing scientific eBook collection ranging from monographs, reference works, field guides, and tutorial texts.

SPIE Press is the largest independent publisher of optics and photonics books - access our growing scientific eBook collection ranging from monographs, reference works, field guides, and tutorial texts.

SPIE Press is the largest independent publisher of optics and photonics books - access our growing scientific eBook collection ranging from monographs, reference works, field guides, and tutorial texts.

SPIE Press is the largest independent publisher of optics and photonics books - access our growing scientific eBook collection ranging from monographs, reference works, field guides, and tutorial texts.

This chapter covers polarizations, two-wave and multiwave interference, slit and circular diffraction, Fresnel equations, Brewster's angle, total internal reflection, and reflectivity and transmissivity.

This chapter first aims to define a few key terms in the context of portable standoff optical spectroscopic sensors for safety and security. It considers sensors that may be moved from one location to another by vehicle, or by man, to be portable. Portable standoff optical spectroscopic sensors fall into three main categories based on the method of operation: point measurement sensors, spatial scanning (mapping) sensors, and wide-field imaging (staring) sensors. The chapter introduces each method and associated subcategories of sensors. It discusses the most common architectures in use by end users for each of the standoff portable instrument types. With so many sensor and underlying technology options, selecting the most appropriate portable standoff optical spectroscopy sensor can be a daunting task. The chapter provides some direction on how to determine which technology is best suited to meet the readers' application needs.

A light wave is an electromagnetic wave, and the wavelength that optics studies ranges from the ultraviolet to the middle infrared. The spatial scales involved in most optical applications are much larger than the light wavelength. In these cases, a light wave can be approximately described by a bundle of straight optical rays. The science of studying optical rays that travel through optical media is called “geometrical optics” and is the most widely used field of optics. If the spatial scales involved are not much larger than the light wavelength, the wave nature of light must be considered; the science of studying the wave nature of light is called “wave optics.”

Optical measurements partially overlap laser beam characterization, so some of the instruments introduced in this chapter can also be used to characterize laser beams. For example, Shack–Hartmann wavefront sensors can be used to characterize laser beam wavefronts. Scanning Fabry–Perot interferometers can be used to analyze the laser beam spectrum.