Abstract: An apparatus and method for differential optical dispersion using a first sample and a second sample are disclosed. The apparatus includes a single frequency chirped laser source configured to generate a single frequency chirped laser beam. A first beam splitter is configured to split the single frequency chirped laser beam into first and second optical branches, the first sample being located in the first optical branch, the second sample being located in the second optical branch. A frequency shifter is located in the second optical branch, downstream of the second sample. A second beam splitter is configured to combine the first and second optical branches and generate a chirp-modulated mixed light beam. A square law detector is configured to detect the chirp-modulated mixed light beam and generate a heterodyne beatnote signal. A demodulator is configured for detection of the heterodyne beatnote signal to generate a transmission/differential optical dispersion spectrum.

Abstract: An apparatus and method for detecting refractive index variations in a sample is disclosed. The apparatus includes a multi frequency laser source configured to generate a mixed laser beam having at least two optical frequencies. A sinusoidal function generator is configured to modulate the optical frequencies to generate a chirp-modulated mixed laser beam. The chirp-modulated mixed laser beam being configured to pass through the sample. A detector is configured to detect the chirp-modulated mixed beam. A signal processer is configured to process the detected chirp-modulated mixed beam to measure refractive index variations in the sample.

Abstract: An apparatus and method for differential optical dispersion using a first sample and a second sample are disclosed. The apparatus includes a single frequency chirped laser source configured to generate a single frequency chirped laser beam. A first beam splitter is configured to split the single frequency chirped laser beam into first and second optical branches, the first sample being located in the first optical branch, the second sample being located in the second optical branch. A frequency shifter is located in the second optical branch, downstream of the second sample. A second beam splitter is configured to combine the first and second optical branches and generate a chirp-modulated mixed light beam. A square law detector is configured to detect the chirp-modulated mixed light beam and generate a heterodyne beatnote signal. A demodulator is configured for detection of the heterodyne beatnote signal to generate a transmission/differential optical dispersion spectrum.

Abstract: An apparatus and method for detecting refractive index variations in a sample is disclosed. The apparatus includes a multi frequency laser source configured to generate a mixed laser beam having at least two optical frequencies. A sinusoidal function generator is configured to modulate the optical frequencies to generate a chirp-modulated mixed laser beam. The chirp-modulated mixed laser beam being configured to pass through the sample. A detector is configured to detect the chirp-modulated mixed beam. A signal processer is configured to process the detected chirp-modulated mixed beam to measure refractive index variations in the sample.