US 8,797,539 B2Granted

System and method for a virtual reference interferometer

OwnerMichael Galleinventor

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Abstract

An interferometer generates interference between two (or more) waves that have traveled separate paths so as to measure a quantity of difference between these paths. One of these paths, the reference path, is usually one with well known spatial and material properties (such as free 5 space). The other path(s) is(are) the test path(s). The main difficulties in interferometry stem from the production and operation of this physical reference path. The present invention solves this problem by replacing the physical reference path with a virtual one. This is done by suitable operation on the physically generated interference pattern of an unreferenced interferometer with a virtually generated sinusoid of frequency corresponding to the desired reference path length. The result is a new form of interferometer called a Virtual Reference Interferometer.

Claims8

Dependent claims

An interferometer system for generating a virtually referenced interference pattern, the system characterized by:

a) a wave generating source operable to emit a wave through one or more test paths;
b) an interferometer with one or more test paths;
e) a detector for measuring a physical spectral interference pattern produced;
d) a processor for modulating and analyzing the physical spectral interference pattern produced in the interferometer;
wherein the physical spectral interference pattern produced in the interferometer is mixed with a simulated virtual reference spectral interference pattern via an operation in the spectral domain;
wherein the result of such operation results in a spectral interference pattern with a high frequency component and a low frequency component;
wherein the low frequency component contains information about the difference between the properties of the one or more test paths and the simulated virtual reference pattern;
wherein the simulated virtual reference pattern balances the group delay in the interferometer at a given wavelength such that the low frequency component is equivalent to that which would be produced by physically balancing the group delay in the interferometer at that wavelength.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/203,186Filed 24 Feb 2010 · us provisional application
Priority: 24 Feb 2009
Published: US 2012/0013908 A119 Jan 2012
Granted: 5 Aug 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

G01B 9/02044
Characterised by particular imaging or detection techniques: imaging in the frequency domain, e.g. by using a spectrometer
G01B 9/02056
Reduction or prevention of errors; Testing; Calibration: passive reduction of errors
G01B 9/02083
Interferometers: characterised by particular signal processing and presentation
G01B 9/02091
Low-coherence interferometers: tomographic interferometers, e.g. based on optical coherence