Abstract: A spectroscope having a high spectroscopic characteristic capable of eliminating a polarization dependence on an arbitrary polarization state of an incident light, and measuring a spectrum having a true central wavelength of the light. The spectroscope comprises: a depolarizer comprising: a first plate a thickness of which continuously changes in a direction of 45 degrees with a first optical axis; and a second plate a thickness of which continuously changes, and which is stuck on the first plate; wherein an angle between the first optical axis and a second optical axis of the second plate, is 45 degrees, and a first reduction direction of the thickness of the first plate and a second reduction direction of the thickness of the second plate is opposite to each other; and a spectroscopic device a dispersion direction of which intersects orthogonally with the first reduction direction.

Abstract: A depolarizing plate comprising a first rectangular wedge plate that has a first crystallographic optical axis in a diagonal direction of the rectangle and which has a thickness thereof in a vertical direction vary continuously in a direction 45 degrees from said first crystallographic optical axis and a second rectangular wedge plate that has a second crystallographic optical axis in a diagonal direction of the rectangle crossing said first crystallographic optical axis at right angles and which has a thickness thereof in a vertical direction vary continuously in a direction 45 degrees from said second crystallographic optical axis, the two wedge plates being joined in such a position that said first crystallographic optical axis crosses said second crystallographic optical axis at right angles, wherein the slope formed by the joint of said wedge plates is rotated about the optical axis of an incident ray of light.

Abstract: A polarization scrambler includes a Faraday element in which the thickness of a direction vertical to an optical axis changes continuously, and a magnetic field generator for generating a magnetic field in a direction of the optical axis with respect to the Faraday element.