| 摘要 |
PURPOSE: To prevent any mode flip phenomenon to be produced by what a reflected light out of the measuring object is returned to a laser illuminant, from occurring by applying a laser beam out of the laser illuminant to the measuring object via an anisotropic Bragg diffraction utilizing acoustic-optical element. CONSTITUTION: A laser beam emitted out of a laser illuminant 10 is horizontally polarized, and when it is taken into an anisotropic diffraction utilizing access- only memory 45, a rectilinear zero-order diffracted light 453 and a first order diffracted light 454 vertically polarized are generated. Since this diffracted light 453 is used as a reference light, it is turned to a beam splitter 27 by a mirror 28. In addition, another diffracted light 454 is applied to a measuring object 30 via mirrors 29, 23, a beam splitter 24, and aλ/4 wavelength plate 25. With this diffracted light 454 utilized as an irradiating light, a reflected return light out of the measuring object 30 will not return to the illuminant 10 so remarkably. Moreover, the first order diffracted light, where the element 45 is produced, is able to cope with both vertical and horizontal polarizations, and also it can be set to the same state as the reference light.
|
