High resolution low noise optical polarimeter
US5477327A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 15, 1993 |
| Grant date | Dec 19, 1995 |
| Priority date | — |
| Expiry date | Dec 15, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/21
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Two linearly polarized beams of monochromatic laser light are amplitude modulated with low frequency sinusoids. The first laser is modulated with a sinusoid 90.degree. out of phase from the second laser. The two beams of laser light have their polarization axis fixed and separated by 45.degree.. These two beams are then collimated and combined into one composite beam using simple optics. This composite beam is then allowed to pass through an optically active substance of a calibrated path length. The laser radiation exiting the sample is passed through a optical notch pass filter, reducing any signal that may be present from any polarized ambient light by passing only light of the laser's frequency. The composite beam then passes into a beam splitting polarizing cube. This cube has the function of separating the beam into two orthogonal polarization components. The two beams of light exiting the cube are focused onto silicon photoelectric detectors. The cube is oriented such that one of the cube's transmission axis is aligned to coincide with the polarization axis of one of the lasers. The current from the detectors is converted into a voltage. The resulting detector voltages are t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.