Abstract:
An apparatus and method for the measurement of at least one parameter of the state of polarization of a light beam is described. The apparatus includes only a photodetector and no other optical elements. The detector surface is partially specularly reflecting and intercepts the light beam at an oblique angle of incidence. The absorbed fraction of incident radiation produces a corresponding electrical output signal that is detected and from which the at least one parameter of the state of polarization can be determined. The detector may also be rotated to modulate the electrical output signal to determine the elliptic polarization of light except for handedness. A two detector ellipsometer is disclosed wherein light reflected from one detector is absorbed by the second detector and the entire system is rotated.
Abstract:
Disclosed is an improved polarimeter and polarimetric method. The heart of the polarimeter is a Faraday rod within a concentric coil. The light being analyzed is imaged at a field stop, passed through the rod and, subsequently, through an analyzer. Electric current pulsed through the coil according to a prescribed waveform creates a pulsed magnetic field within the rod, causing the plane of polarization of the incoming light to rotate by an amount varying according to the particular current waveform. This, in turn, creates a varying degree of attenuation, by the analyzer, of the plane polarized component of the light. Means are provided for measuring this variation of attenuation, by which measurement the degree and angle of polarization of the incoming light may be determined, as well as the intensity thereof.