Nonlinear optical imaging
Phase modulated Optical Parametric Amplification Imaging (p-OPA), can be used to determine the magnitude and the sign of the second-order nonlinear susceptibility of a material, and its spatial variation.
1. A system for detecting optical parametric amplification comprising
a source of a first laser beam having a first frequency and a second laser beam having a second frequency, wherein the first frequency is two times the second frequency and at least one of the first laser beam and the second laser beam have a modulated phase;
a modulation unit of source that controls the modulated phase of the first laser beam and second laser beam such that if a sample is active for optical parametric amplification, phase modulation leads to intensity exchange between the two laser pulses,
a sample holder configured to hold a sample that contacts the first laser beam and the second laser beam;
a lock-in amplifier;
a detector configured to detect the first laser beam, the second laser beam, or both after contacting the sample, wherein the lock-in amplifier and detector extract intensity of the detected beam using the modulated phase.
2. The system of claim 1 , wherein the first laser beam is phase modulated.
3. The system of claim 1 , wherein the second laser beam is phase modulated.
4. The system of claim 1 , wherein the first laser beam and the second laser beam are phase modulated.
5. The system of claim 1 , wherein the detector detects the first laser beam after contacting the sample.
6. The system of claim 1 , wherein the detector detects the second laser beam after contacting the sample.
7. The system of claim 1 , wherein the detector detects the first laser beam and the second laser beam after contacting the sample.
8. The system of claim 1 , wherein the lock-in amplifier and detector extract phase of the detected beam.
9. The system of claim 1 , further comprising a display module for displaying image data from the detected intensity.
10. A method of optical parametric amplification comprising
supplying a first laser beam having a first frequency and a second laser beam having a second frequency, wherein the first frequency is two times the second frequency and at least one of the first laser beam and the second laser beam have a modulated phase;
exposing a sample to the first laser beam, the second laser beam, or both;
detecting intensity of the first laser beam, the second laser beam, or both after contacting the sample using the modulated phase.
11. The method of claim 10 , wherein the first laser beam is phase modulated.
12. The method of claim 10 , wherein the second laser beam is phase modulated.
13. The method of claim 10 , wherein the first laser beam and the second laser beam are phase modulated.
14. The method of claim 10 , wherein the first laser beam is detected after contacting the sample.
15. The method of claim 10 , wherein the second laser beam is detected after contacting the sample.
16. The method of claim 10 , wherein the first laser beam and the second laser beam are detected after contacting the sample.
17. The method of claim 10 , wherein detecting includes identifying the phase of a detected beam.
18. The method of claim 10 , further comprising displaying image data from the detected intensity.