Noise cancellation in fourier transform spectrophotometry
First Claim
Patent Images
1. A spectrophotometry system comprising:
- an interferometer for receiving, from a light source, a source light beam and introducing interference effects thereto;
a sealed housing for receiving, from the interferometer, the source light beam having the interference effects;
an optical system within the housing for splitting the source light beam having the interference effects into a reference beam and a sample beam and for directing the reference beam and the sample beam in separate paths;
a reference compartment within the housing, said reference compartment including a reference for interacting with the reference beam wherein said interacting yields an output reference beam having a direction;
a reference light detector for detecting at least a portion of the output reference beam based on the direction of the output reference beam and generating a reference signal representative of the detected light;
a sample compartment within the housing, said sample compartment including a sample for interacting with the sample beam wherein said interacting yields an output sample beam having a direction;
a sample light detector for detecting at least a portion of the output sample beam based on the direction of the output sample beam and generating a sample signal representative of the detected light;
a detector circuit for producing a reference voltage proportional to the reference signal and a difference voltage proportional to the difference between the reference signal and the sample signal; and
a processor configured to determine a spectrum of the sample based on the difference voltage, wherein said processor is configured to generate an interferogram from the difference voltage and to calculate a Fourier Transform of the interferogram, said spectrum being a function of the Fourier Transform of the interferogram.
1 Assignment
0 Petitions
Accused Products
Abstract
Increasing signal to noise ratio in optical spectra obtained by spectrophotometers. An interferometer introduces interference effects into a source light beam. A dual beam configuration splits the source beam having the interference effects into a reference beam and a sample beam. The reference beam interacts with a reference substance and is detected by a reference detector. The sample beam interacts with a sample substance and is detected by a sample detector. An optical spectra of the sample is based on the difference between the detected reference beam and the detected sample beam.
-
Citations
18 Claims
-
1. A spectrophotometry system comprising:
-
an interferometer for receiving, from a light source, a source light beam and introducing interference effects thereto; a sealed housing for receiving, from the interferometer, the source light beam having the interference effects; an optical system within the housing for splitting the source light beam having the interference effects into a reference beam and a sample beam and for directing the reference beam and the sample beam in separate paths; a reference compartment within the housing, said reference compartment including a reference for interacting with the reference beam wherein said interacting yields an output reference beam having a direction; a reference light detector for detecting at least a portion of the output reference beam based on the direction of the output reference beam and generating a reference signal representative of the detected light; a sample compartment within the housing, said sample compartment including a sample for interacting with the sample beam wherein said interacting yields an output sample beam having a direction; a sample light detector for detecting at least a portion of the output sample beam based on the direction of the output sample beam and generating a sample signal representative of the detected light; a detector circuit for producing a reference voltage proportional to the reference signal and a difference voltage proportional to the difference between the reference signal and the sample signal; and a processor configured to determine a spectrum of the sample based on the difference voltage, wherein said processor is configured to generate an interferogram from the difference voltage and to calculate a Fourier Transform of the interferogram, said spectrum being a function of the Fourier Transform of the interferogram. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A spectrophotometry device, comprising:
-
a Michelson interferometer for receiving, from a light source, a source light beam and introducing interference effects thereto; a sealed housing; a first beam splitter within the housing and in optical communication with the output of the interferometer, said first beam splitter having a transmissive side and a reflective side; a second beam splitter within the housing and in optical communication with the transmissive side of said first beam splitter; a third beam splitter within the housing and in optical communication with the reflective side of said first beam splitter; a reference detecting system within the housing and in optical communication with one of said second and third beam splitters; and a sample detecting system within the housing and in optical communication with the other of said second and third beam splitters. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
-
18. A method of determining an optical spectrum for a sample substance, said method comprising:
-
receiving a source beam from an external light source, said source beam comprising having a plurality of wavelengths; introducing interference effects into the source beam; splitting the source beam comprising the interference effects into a reference beam and a sample beam; directing the reference beam into a reference cell having a reference substance therein, said reference substance interacting with the reference beam, said interacting yielding an output reference beam having a direction; directing the sample beam into a sample cell having the sample substance therein, said sample substance interacting with the sample beam, said interacting yielding an output sample beam having a direction; detecting at least a portion of the output reference beam and at least a portion of the output sample beam; generating a reference signal representative of the detected portion of the output reference beam and a sample signal representative of the detected portion of the output sample beam; generating a reference voltage proportional to the reference signal and a difference voltage proportional to the difference between the reference signal the sample signal; generating an interferogram from the difference voltage; calculating a Fourier Transform of the interferogram; and determining a spectrum of the sample as a function of the calculated Fourier Transform of the interferogram.
-
Specification