Method and system for spectral analysis of biological materials using stimulated cars
First Claim
1. A CARS system for probing a Raman signature of a sample, comprising at least one laser producing a femtosecond laser pulse;
- a beam splitter splitting the femtosecond laser pulse into a stimulus pulse and a probe pulse;
a first spectral phase modulator modulating a phase or a polarization, or both, of the stimulus pulse;
a second spectral phase modulator modulating a phase or polarization, or both, of the probe pulse;
an optical delay line for time-delaying the modulated probe pulse with respect to the stimulus pulse; and
a spectral analyzer that detects the Raman signature of the sample in response to the probe pulse and after stimulation of the sample by the stimulus pulse.
2 Assignments
0 Petitions
Accused Products
Abstract
A CARS system and method for probing a Raman signature of a sample are described. A short femtosecond pulse from one or more lasers is split into two pulses, a stimulus pulse and a probe pulse, whereby the probe pulse is time-delayed with respect to the stimulus pulse. Both pulses can be phase- and polarization-modulated. The stimulus pulse excites a vibronic level in the sample and the probe pulse probes molecular Raman transitions in the sample. A difference in the signals with and without excitation can be used to determine on which molecule a bond is most likely located. This will allow an accurate and sensitive determination of the presence of specific molecules in the sample. The system and method can be used to analyze biological samples and to discriminate between molecules having overlapping Raman signatures.
66 Citations
24 Claims
-
1. A CARS system for probing a Raman signature of a sample, comprising
at least one laser producing a femtosecond laser pulse; -
a beam splitter splitting the femtosecond laser pulse into a stimulus pulse and a probe pulse;
a first spectral phase modulator modulating a phase or a polarization, or both, of the stimulus pulse;
a second spectral phase modulator modulating a phase or polarization, or both, of the probe pulse;
an optical delay line for time-delaying the modulated probe pulse with respect to the stimulus pulse; and
a spectral analyzer that detects the Raman signature of the sample in response to the probe pulse and after stimulation of the sample by the stimulus pulse. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method for identifying molecules in a molecular system based on a stimulated CARS signature, comprising:
-
a. providing a first optical probe pulse and measuring a first CARS response signal from the molecular system;
b. providing an optical stimulus pulse and a second optical probe pulse that is time-delayed with respect to the stimulus pulse;
c. measuring with the second optical probe pulse a second CARS response signal from the molecular system;
d. subtracting the first CARS response signal from the second CARS response signal to form a difference signal;
e. repeating steps a) through e) with a different optical stimulus pulse; and
f. identifying molecules and a concentration of the molecules in the molecular system based on the difference signal. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
Specification