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Title: Variable thickness double-refracting plate

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 varyingmore » output light amplitude whose average corresponds to the amount of the trace element present in the sample.« less

Inventors:
 [1]
  1. Berkeley, CA
Issue Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
862538
Patent Number(s):
3957375
Assignee:
United States of America as represented by United States Energy (Washington, DC)
Patent Classifications (CPCs):
G - PHYSICS G02 - OPTICS G02F - DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING
G - PHYSICS G02 - OPTICS G02B - OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
variable; thickness; double-refracting; plate; provides; cyclic; current-controlled; phase; retardation; magnetic; clamp; produce; stress; birefringence; developed; isotope-zeeman; atomic; absorption; spectrometer; polarization; modulation; effect; automatic; background; correction; trace-element; measurements; photoelastic; alternately; stressed; released; selectively; modulate; specific; components; selected; consisting; circularly; plane; polarized; zeeman; produced; dc; field; correspond; respectively; reference; transmission-probe; changes; designated; sigma; half; cycle; change; transmission; mode; component; blocked; transmitted; corresponds; amplitude; amount; trace; element; measured; sample; linear; polarizer; continuously; result; sinusoidally; varying; output; light; average; output light; atomic absorption; trace element; magnetic field; variable thickness; circularly polarized; dc magnet; transmission mode; circularly polarize; absorption spectrometer; /356/359/

Citation Formats

Hadeishi, Tetsuo. Variable thickness double-refracting plate. United States: N. p., 1976. Web.
Hadeishi, Tetsuo. Variable thickness double-refracting plate. United States.
Hadeishi, Tetsuo. Thu . "Variable thickness double-refracting plate". United States. https://www.osti.gov/servlets/purl/862538.
@article{osti_862538,
title = {Variable thickness double-refracting plate},
author = {Hadeishi, Tetsuo},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1976},
month = {1}
}

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