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Techniques for recovering optical spectral features using a chirped optical field
Assignee: Montana State University – Bozeman
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Filing: 2005-07-12
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Granted: 2006-12-05
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Expires: 2025-07-12
Abstract
Abstract Techniques for recovering optical spectral features include receiving a detected time series that represents a temporally varying intensity of an optical signal. The optical signal is formed in response to an interaction between a target optical spectrum and a chirped optical field. The chirped optical field is an optical field that has a monochromatic frequency that varies in time. The target optical spectrum is an optical frequency dependent optical property of a material or device. A phase correction factor is determined based only on one or more properties of the chirped optical field. The detected time series is corrected based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency. These techniques allow for fast measurement of spectral features and eliminate the need for prior knowledge of the target optical spectrum to adjust the chirp rate.
Inventors
- 👤 Tiejun Chang
- 👤 Mingzhen Tian
- 👤 William R. Babbitt
- 👤 Kristian Merkel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:19
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/02; G01J3/0264; G01J3/28; G01J3/2889; G01J3/42; G01J3/433; G01J3/4338; G01J3/45
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
128 words
A method for recovering optical spectral features using a chirped optical field, comprising the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between a target optical spectrum and a chirped optical field, wherein the chirped optical field is an optical field that has a monochromatic frequency that varies in time, and the target optical spectrum in an optical frequency dependent optical property of a material or device; determining a phase correction factor based only on one or more properties of the chirped optical field; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 2
Independent Claim
128 words
A method for recovering optical spectral features using a chirped optical field, comprising the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between a target optical spectrum and a chirped optical field, wherein the chirped optical field is an optical field that has a monochromatic frequency that varies in time, and the target optical spectrum in an optical frequency dependent optical property of a material or device; determining a phase correction factor based only on one or more properties of the chirped optical field; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 3
Dependent Claim
29 words
A method as recited in claim 1 , said step of determining the phase correction factor further comprising determining the phase correction factor based on a quadratic phase term.
Claim 4
Dependent Claim
47 words
A method as recited in claim 1 , wherein: the chirped optical field has a plurality of well-known values for a corresponding plurality of well-known properties; and said step of determining the phase correction factor further comprising determining the phase correction factor based on the well-known values.
Claim 5
Dependent Claim
51 words
A method as recited in claim 3 , wherein the plurality of well-known properties include: a constant chirp rate (κ) that indicates a change in frequency of the chirped optical field with time, and a start frequency (νs) that indicates an initial frequency at a start of the chirped optical field.
Claim 6
Dependent Claim
72 words
A method as recited in claim 4 , said step of determining the phase correction factor further comprising determining a frequency (ν) dependent correction factor based on a chirped phase term φc given by the equation ti φ c=exp[i π(2 νsν−ν 2 )/κ] that includes an effect of a quadratic phase, where i is the square root of −1 and π is the well known ratio of a circumference to a diameter.
Claim 7
Dependent Claim
76 words
A method as recited in claim 5 , said step of correcting the detected time series based on the phase correction factor further comprising: determining a Fourier transform of the detected time series; multiplying the Fourier transform of the detected time series by the correction factor equal to the reciprocal of the phase term φc to produce a corrected transform; and determining an inverse Fourier transform of the corrected transform to produce the output time series.
Claim 8
Dependent Claim
63 words
A method as recited in claim 5 , said step of correcting the detected time series based on the phase correction factor further comprising: determining an inverse Fourier transform of the correction factor equal to the reciprocal of the phase term φc to produce a transformed correction; and convolving the transformed correction with the detected time series to produce the output time series.
Claim 9
Dependent Claim
27 words
A method as recited in claim 1 , said step of determining the phase correction factor further comprising determining a Fourier transform of the chirped optical field.
Claim 10
Dependent Claim
80 words
A method as recited in claim 8 , said step of correcting the detected time series based on the phase correction factor further comprising: determining a Fourier transform of the detected time series; multiplying the Fourier transform of the detected time series by the correction factor proportional to the reciprocal of the Fourier transform of the chirped optical field to produce a corrected transform; and determining an inverse Fourier transform of the corrected transform to produce the output time series.
Claim 11
Dependent Claim
85 words
A method as recited in claim 1 , said step of receiving a detected time series further comprising receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between a chirped reference optical field and a response signal, wherein: the response signal is due to the interaction of the target optical spectrum and the chirped optical field, and the chirped reference optical field is selected to produce a detectable heterodyne signal at an optical detector.
Claim 12
Independent Claim
119 words
A method for recovering optical spectral features using a chirped optical grating, comprising the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between an incident optical field having a target optical spectrum and a material with a chirped spectral grating, wherein the chirped spectral grating is a spectral grating of grating period that varies with optical frequency, and determining a phase correction factor based only on one or more properties of the chirped spectral grating; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 13
Independent Claim
119 words
A method for recovering optical spectral features using a chirped optical grating, comprising the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between an incident optical field having a target optical spectrum and a material with a chirped spectral grating, wherein the chirped spectral grating is a spectral grating of grating period that varies with optical frequency, and determining a phase correction factor based only on one or more properties of the chirped spectral grating; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 14
Dependent Claim
157 words
A computer-readable medium carrying one or more sequences of instructions for recovering spectral features using a chirped optical field, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between a target optical spectrum and a chirped optical field, wherein the chirped optical field is an optical field that has a monochromatic frequency that varies in time, and the target optical spectrum is an optical frequency dependent optical property of a material or device; determining a phase correction factor based only on one or more properties of the chirped optical field; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 15
Dependent Claim
157 words
A computer-readable medium carrying one or more sequences of instructions for recovering spectral features using a chirped optical field, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between a target optical spectrum and a chirped optical field, wherein the chirped optical field is an optical field that has a monochromatic frequency that varies in time, and the target optical spectrum is an optical frequency dependent optical property of a material or device; determining a phase correction factor based only on one or more properties of the chirped optical field; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 16
Dependent Claim
30 words
A computer-readable medium as recited in claim 12 , said step of determining the phase correction factor further comprising determining the phase correction factor based on a quadratic phase term.
Claim 17
Dependent Claim
48 words
A computer-readable medium as recited in claim 12 , wherein: the chirped optical field has a plurality of well-known values for a corresponding plurality of well-known properties; and said step of determining the phase correction factor further comprising determining the phase correction factor based on the well-known values.
Claim 18
Dependent Claim
52 words
A computer-readable medium as recited in claim 14 , wherein the plurality of well-known properties include: a constant chirp rate (κ) that indicates a change in frequency of the chirped optical field with time, and a start frequency (νs) that indicates an initial frequency at a start of the chirped optical field.
Claim 19
Dependent Claim
73 words
A computer-readable medium as recited in claim 15 , said step of determining the phase correction factor further comprising determining a frequency (ν) dependent correction factor based on a chirped phase term φc given by the equation ti φ c=exp[i π(2 νsν−ν 2 )/κ] that includes an effect of a quadratic phase, where i is the square root of −1 and π is the well known ratio of a circumference to a diameter.
Claim 20
Dependent Claim
77 words
A computer-readable medium as recited in claim 16 , said step of correcting the detected time series based on the phase correction factor further comprising: determining a Fourier transform of the detected time series; multiplying the Fourier transform of the detected time series by the correction factor equal to the reciprocal of the phase term φc to produce a corrected transform; and determining an inverse Fourier transform of the corrected transform to produce the output time series.
Claim 21
Dependent Claim
64 words
A computer-readable medium as recited in claim 16 , said step of correcting the detected time series based on the phase correction factor further comprising: determining an inverse Fourier transform of the correction factor equal to the reciprocal of the phase term φc to produce a transformed correction; and convolving the transformed correction with the detected time series to produce the output time series.
Claim 22
Dependent Claim
81 words
A computer-readable medium as recited in claim 18 , said step of correcting the detected time series based on the phase correction factor further comprising: determining a Fourier transform of the detected time series; multiplying the Fourier transform of the detected time series by the correction factor proportional to the reciprocal of the Fourier transform of the chirped optical field to produce a corrected transform; and determining an inverse Fourier transform of the corrected transform to produce the output time series.
Claim 23
Dependent Claim
28 words
A computer-readable medium as recited in claim 12 , said step of determining the phase correction factor further comprising determining a Fourier transform of the chirped optical field.
Claim 24
Dependent Claim
148 words
A computer-readable medium carrying one or more sequences of instructions for recovering spectral features using a chirped optical field, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between an incident optical field having a target optical spectrum and a material with a chirped spectral grating, wherein the chirped spectral grating is a spectral grating of grating period that varies with optical frequency, and determining a phase correction factor based only on one or more properties of the chirped spectral grating; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
Claim 25
Dependent Claim
148 words
A computer-readable medium carrying one or more sequences of instructions for recovering spectral features using a chirped optical field, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of: receiving a detected time series that represents a temporally varying intensity of an optical signal in response to an interaction between an incident optical field having a target optical spectrum and a material with a chirped spectral grating, wherein the chirped spectral grating is a spectral grating of grating period that varies with optical frequency, and determining a phase correction factor based only on one or more properties of the chirped spectral grating; and correcting the detected time series based on the phase correction factor to produce an output time series that reproduces in time a shape of the target spectrum in frequency.
References Cited (Backward Citations)
US5928146A
Cited
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