System for improving the sensitivity and stability of optical polarimetric measurements
US6370407B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 12, 2000 |
| Grant date | Apr 9, 2002 |
| Priority date | — |
| Expiry date | Sep 1, 2020 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B5/7257
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A polarimeter adapted for measurement of the concentration of glucose in a sample includes a laser beam passing through a first polarizer and an optical modulator and split into a measurement beam passing through a FIRST ANALYZER to a first detector coupled to a first amplifier and a reference beam passing through a SECOND ANALYZER to a second detector coupled to a second amplifier. Identical multiple filtering and summing operations are performed on outputs of the first and second amplifiers to produce a first &PSgr;2/2 signal and a first 2&bgr;&PSgr; signal in response to the measurement beam and a second &PSgr;2/2 signal and a second 2&bgr;&PSgr; signal in response to the reference beam. The measurement beam is stabilized by comparing the second &PSgr;2/2 signal to a first reference signal to produce a first error signal and comparing the second 2&bgr;&PSgr; signal to a second reference signal to produce a second error signal. The first error signal is multiplied by a modulation signal to produce a modulation feedback signal and adding it to the second error signal to produce a combined modulation and zeroing feedback signal which drives the optical modulator so as to minimize t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.