激光出现以后，人们获得了高强度、高单色性的相干光源，在许多实际问题中，将遇到繁杂的菲涅耳衍射的计算。
Since laser appeared, pure monochromatic coherent light sources of high intensity have been achieved. In many practical problems, there are miscellaneous Fresnel's diffraction calculations.
强度法是干涉型传感器采用的最古老、最简单的方法，它采用单色激光光源作为系统的光源。
The intensity modulation method is the oldest and simplest method for fiber-optic sensor, in which a homochromatic laser is used as system light source.
单色器可以把有用的特征波长分开，检测器用来测定发射光的强度。
A monochromator can separate specific wavelengths of interest, and a detector l, used to measures the intensity of the emitted light.
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