Electro-optic sampling probe

摘要

The electro-optic sampling probe of the present invention comprising: an electro-optic element that is connected to wiring on a surface of a wafer to be measured and whose optical characteristics change when an electric field is applied via the wiring; and an electro-optic sampling optical system module that is provided internally with polarizing beam splitters, wavelength plates, and photodiodes and that splits laser beam irradiated from outside that is transmitted through the electro-optic element and is further reflected at a surface of the electro-optic element that faces the wiring and converts it into electrical signals. Furthermore, the electro-optic sampling optical system module comprises: a ¼wavelength plate for changing laser beam that is elliptically polarized back into linearly polarized light before it enters the electro-optic sampling optical system module; and a ½wavelength plate for adjusting a polarization direction of the linearly polarized light.