Optics: measuring and testing – Range or remote distance finding – With photodetection
Patent
1974-07-23
1976-05-18
Corbin, John K.
Optics: measuring and testing
Range or remote distance finding
With photodetection
350149, 356 97, G02F 129
Patent
active
039573753
ABSTRACT:
This invention provides an A.C., cyclic, current-controlled, phase retardation plate that uses a magnetic clamp to produce stress birefringence. It was developed for an Isotope-Zeeman Atomic Absorption Spectrometer that uses polarization modulation to effect automatic background correction in atomic absorption trace-element measurements. To this end, the phase retardation plate of the invention is a variable thickness, photoelastic, double-refracting plate that is alternately stressed and released by the magnetic clamp selectively to modulate specific components selected from the group consisting of circularly and plane polarized Zeeman components that are produced in a dc magnetic field so that they correspond respectively to Zeeman reference and transmission-probe absorption components. The polarization modulation changes the phase of these polarized Zeeman components, designated as .sigma. reference and .pi. absorption components, so that every half cycle the components change from a transmission mode to a mode in which the .pi. component is blocked and the .sigma. components are transmitted. Thus, the Zeeman absorption component, which corresponds in amplitude to the amount of the trace element to be measured in a sample, is alternately transmitted and blocked by a linear polarizer, while the circularly polarized reference components are continuously transmitted thereby. The result is a sinusoidally varying output light amplitude whose average corresponds to the amount of the trace element present in the sample.
REFERENCES:
patent: 2753754 (1956-07-01), Le Clair
patent: 3495912 (1970-02-01), Hooper et al.
hadeishi et al., "Hyperfine Zeeman Effect Atomic Absorption Spectrometer for Mercury," Science, Vol. 174, oct. 22, 1971, pp. 404-407.
Belkin Leonard
Carlson Dean E.
Corbin John K.
Cornish Cornell D.
Evans F. L.
LandOfFree
Variable thickness double-refracting plate does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Variable thickness double-refracting plate, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable thickness double-refracting plate will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2232301