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A chirped mirror is a dielectric mirror with chirped spaces—spaces of varying depth designed to reflect varying wavelengths of lights—between the dielectric layers (stack). Chirped mirrors are used in applications like lasers to reflect a wider range of light wavelengths than ordinary dielectric mirrors, or to compensate for the dispersion of wavelengths that can be created by some optical elements. ==Simple explanation== An ordinary dielectric mirror is made to reflect a single frequency of light. The dielectric mirror is made of transparent materials that are uniformly layered at a depth of 1/4 the wavelength of light the dielectric mirror is designed to reflect. The dielectric mirror is transparent to other wavelengths of light except those in a very narrow band around the wavelength it is designed to reflect. A chirped mirror is made to reflect a wider range of frequencies. This is done by creating layers with different depths. There may be 10 layers with a depth designed to reflect a certain wavelength of light, another 10 layers with slightly greater depth to reflect a slightly longer wavelength of light, and so on for the entire range of wavelengths of light the mirror is designed to reflect. The result is a mirror that can reflect a whole range of light wavelengths rather than single narrow band of wavelengths. Because light reflected from the deeper layers of the mirror travels a longer distance than the light that reflects off the surface layers, a chirped mirror can be designed to change the relative times of wavefronts of different wavelength reflecting from it. This may be used, for example, to disperse a pulse of light of different wavelengths that arrives all at one time or to tighten a pulse of light where different wavelengths arrive dispersed in time. This ability to tighten or more tightly pack a pulse of light of different wavelengths is important, because some commonly used optical elements naturally disperse a packet of light according to wavelength, a phenomenon known as chromatic dispersion. A chirped mirror can be designed to compensate for the chromatic dispersion created by other optical elements in a system. This is a simplified explanation and omits some important but more complex technical considerations. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chirped mirror」の詳細全文を読む スポンサード リンク
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