Optical method and system for analyzing or inspecting patterned materials
A method to determine at least one characteristic of a material having a spatially modulated nonlinear susceptibility includes measuring scattered light in response to an incident beam provided to at least one surface of the material. An indication of patterning of the material is determined based on the measured scattered light.
1. A method to determine at least one characteristic of a material having a spatially modulated nonlinear susceptibility, comprising:
measuring scattered light in response to an incident beam provided to at least one surface of the material; and
determining an indication of patterning of the material based on the measured scattered light.
2. The method of claim 1 , further comprising:
scanning the incident beam across at least two adjacent domains of the material to provide the scattered light; and
discriminating between the at least two adjacent domains based on a modulation of intensity for at least one type of phonon in the scattered light.
3. The method of claim 2 , further comprising providing predetermined selection rules according to a type of the material,
wherein the determination of the patterning further comprises employing a subset of the predetermined selection rules to facilitate determining the indication of patterning for the at least two adjacent domains.
4. The method of claim 3 , wherein the predetermined selection rules are adjusted to characterize at least one known symmetry-breaking effect associated with the material.
5. The method of claim 2 , wherein the incident beam has a beam width or spot size at the surface of the material that is less than a width of each of the at least two adjacent domains.
6. The method of claim 1 , wherein the indication of patterning is determined by calculating a frequency at which at least one type of phonon modulates in intensity based on the scattered light.
7. The method of claim 6 , wherein the at least one type of phonon comprises at least one of a longitudinal optical phonon, a transverse optical phonon, a longitudinal acoustic phonon, and a transverse acoustic phonon.
8. The method of claim 1 , further comprising providing the incident beam as a linearly polarized beam having a predetermined polarization.
9. The method of claim 1 , further comprising performing a fast-Fourier transform to convert a time domain representation of the measured scattered light into a frequency domain representation, such that peaks in intensity of the frequency domain representation correspond to a frequency associated with at least one type of phonon that defines the indication of patterning.
10. The method of claim 1 , wherein the input beam has a frequency that is in resonance with an electronic transition of the material.
11. The method of claim 1 , wherein the material comprises a crystal film grown on a substrate, the method further comprising scanning the incident beam across a plurality of domains of the material to provide the scattered light.
12. A system to determine a characteristic of a nonlinear crystalline material, comprising:
means for determining a modulation in intensity of phonons in scattered light from the material; and
means for determining an indication of patterning of the material based on the determined modulation in phonon intensity.
13. The system of claim 12 , further comprising:
means for scanning an incident beam across at least two adjacent domains of at least one surface of the material to provide the scattered light from the material.
14. The system of claim 13 , wherein the incident beam is provided as a linearly polarized beam having a predetermined polarization.
15. The system of claim 13 , wherein the incident beam impinges the material with a beam width or spot size that is less than a width of adjacent domains.
16. The system of claim 13 , wherein the input beam has a frequency that is in resonance with an electronic transition of the material.
17. The system of claim 12 , wherein the means for determining an indication of patterning employs predetermined phonon selection rules selected according to at least one of a type of the material and an expected orientation of the material.
18. The system of claim 12 , wherein the material comprises a crystal film grown on a substrate, the incident beam scanning across the surface of the material to provide the scattered light for a plurality of orientation-patterned domains of the material.
19. A system to analyze a material, comprising:
a light source that provides an incident beam having a predetermined polarization and a predetermined frequency;
a detection system configured to detect scattered light from at least two adjacent domains of the material in response to the incident beam impinging on the at least two adjacent domains; and
a computer programmed to determine an indication of patterning for the material based on detected scattered light.
20. The system of claim 19 , wherein the incident beam impinges on the material with a width that is less than a width of adjacent domains, the incident beam also having a frequency that is in resonance with an electronic transition of the material, such that by scanning the incident beam across at least two adjacent domains of the material the scattered light is provided with a modulation in phonon intensity, the computer determining the indication of patterning for the material based on the modulation of phonon intensity.