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Title: Achromatic self-referencing interferometer

Abstract

A self-referencing Mach-Zehnder interferometer for accurately measuring laser wavefronts over a broad wavelength range (for example, 600 nm to 900 nm). The apparatus directs a reference portion of an input beam to a reference arm and a measurement portion of the input beam to a measurement arm, recombines the output beams from the reference and measurement arms, and registers the resulting interference pattern ("first" interferogram) at a first detector. Optionally, subportions of the measurement portion are diverted to second and third detectors, which respectively register intensity and interferogram signals which can be processed to reduce the first interferogram's sensitivity to input noise. The reference arm includes a spatial filter producing a high quality spherical beam from the reference portion, a tilted wedge plate compensating for off-axis aberrations in the spatial filter output, and mirror collimating the radiation transmitted through the tilted wedge plate. The apparatus includes a thermally and mechanically stable baseplate which supports all reference arm optics, or at least the spatial filter, tilted wedge plate, and the collimator. The tilted wedge plate is mounted adjustably with respect to the spatial filter and collimator, so that it can be maintained in an orientation in which it does not introducemore » significant wave front errors into the beam propagating through the reference arm. The apparatus is polarization insensitive and has an equal path length configuration enabling measurement of radiation from broadband as well as closely spaced laser line sources.« less

Inventors:
 [1]
  1. Pleasanton, CA
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
OSTI Identifier:
869244
Patent Number(s):
US 5305074
Assignee:
United States of America as represented by United States (Washington, DC)
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
achromatic; self-referencing; interferometer; mach-zehnder; accurately; measuring; laser; wavefronts; broad; wavelength; range; example; 600; nm; 900; apparatus; directs; reference; portion; input; beam; arm; measurement; recombines; output; beams; arms; registers; resulting; interference; pattern; interferogram; detector; optionally; subportions; diverted; third; detectors; respectively; register; intensity; signals; processed; reduce; sensitivity; noise; spatial; filter; producing; quality; spherical; tilted; wedge; plate; compensating; off-axis; aberrations; mirror; collimating; radiation; transmitted; thermally; mechanically; stable; baseplate; supports; optics; collimator; mounted; adjustably; respect; maintained; orientation; introduce; significant; wave; front; errors; propagating; polarization; insensitive; equal; path; length; configuration; enabling; broadband; closely; spaced; line; sources; mechanically stable; spatial filter; output beams; radiation transmitted; reference portion; wave front; wavelength range; input beam; interference pattern; path length; output beam; closely spaced; accurately measuring; measuring laser; line source; filter output; mach-zehnder interferometer; /356/

Citation Formats

Feldman, Mark. Achromatic self-referencing interferometer. United States: N. p., 1994. Web.
Feldman, Mark. Achromatic self-referencing interferometer. United States.
Feldman, Mark. Sat . "Achromatic self-referencing interferometer". United States. https://www.osti.gov/servlets/purl/869244.
@article{osti_869244,
title = {Achromatic self-referencing interferometer},
author = {Feldman, Mark},
abstractNote = {A self-referencing Mach-Zehnder interferometer for accurately measuring laser wavefronts over a broad wavelength range (for example, 600 nm to 900 nm). The apparatus directs a reference portion of an input beam to a reference arm and a measurement portion of the input beam to a measurement arm, recombines the output beams from the reference and measurement arms, and registers the resulting interference pattern ("first" interferogram) at a first detector. Optionally, subportions of the measurement portion are diverted to second and third detectors, which respectively register intensity and interferogram signals which can be processed to reduce the first interferogram's sensitivity to input noise. The reference arm includes a spatial filter producing a high quality spherical beam from the reference portion, a tilted wedge plate compensating for off-axis aberrations in the spatial filter output, and mirror collimating the radiation transmitted through the tilted wedge plate. The apparatus includes a thermally and mechanically stable baseplate which supports all reference arm optics, or at least the spatial filter, tilted wedge plate, and the collimator. The tilted wedge plate is mounted adjustably with respect to the spatial filter and collimator, so that it can be maintained in an orientation in which it does not introduce significant wave front errors into the beam propagating through the reference arm. The apparatus is polarization insensitive and has an equal path length configuration enabling measurement of radiation from broadband as well as closely spaced laser line sources.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1994},
month = {1}
}

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