Patent ID: 9448056
Filing Date: 2016-09-20
CPC Classification: G01B

Claim Text:
1. A multi-frequency interferometric imager, comprising: a swept frequency light source configured to generate a narrowband light signal whose frequency is swept as a function of time; a light signal manipulator configured to receive the light signal from the swept frequency light source and to output a reference signal and a sample signal; a reference arm optical conduit optically coupled to the light signal manipulator to receive the reference signal from the light signal manipulator and to send the reference signal back to the signal manipulator; a sample arm optical conduit optically coupled to the light signal manipulator to receive the sample signal, the sample arm optical conduit being optically coupled to a sample unit that holds a sample and sends the sample signal back to the signal manipulator; the signal manipulator being configured to combine the reference signal and the sample signal to output a first signal and a second signal with a first phase difference therebetween and to output a third signal and a fourth signal with a second phase difference therebetween; first and second single-channel detectors optically coupled to the signal manipulator and configured to receive the first, second, third and fourth signals from the signal manipulator to simultaneously acquire a first spectrum and a second spectrum having the first phase difference therebetween and to simultaneously acquire a third spectrum and a fourth spectrum having the second phase difference therebetween; a processor configured to determine a first difference spectrum between the first and second spectra, to determine a second difference spectrum between the first and second spectra, the first and second spectra having orthogonal phase to the third and fourth spectra, respectively; to generate a complex Fourier-domain dataset from the first and second difference spectra, wherein the first difference spectrum comprises a real part of the complex Fourier-domain dataset and a second difference spectrum comprises an imaginary part of the complex Fourier-domain dataset; to generate an inverse Fourier transform from the complex Fourier-domain dataset; and to generate an image of at least a portion of a sample based on the inverse Fourier transform, wherein the signal manipulator comprises a first fiber coupler optically coupled to a second fiber coupler and an optical circulator optically coupled to a first fiber coupler; wherein the reference arm optical conduit and the sample arm optical conduit are each optically coupled to the first fiber coupler so as to receive a signal from the first fiber coupler; wherein the reference arm optical conduit is configured to receive a signal from the first fiber coupler and output a signal to the second fiber coupler and at least one of the first and second detectors is optically coupled to the first and second fiber coupler so as to receive a signal from the first fiber coupler and a signal from the second fiber coupler, wherein the first and second fiber couplers comprise ports having a predefined phase delay that provide the first phase difference between the first spectrum and the second spectrum and the second phase difference between the third spectrum and the fourth spectrum, such that the first and second spectra have an orthogonal phase to the third and fourth spectra, respectively.