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US 12,742,635 B2Granted
Layer thickness determination by four-wave-mixing spectroscopy
AssigneeMonstr Sense Technologies, LLC
InventorsEric W. Martin, Torben L. Purz, Steven T. Cundiff
Life of this patent
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Abstract
A method determines the number of layers in a sample material. The method includes measuring, as a function of two or more wavelengths, a four-wave mixing (FWM) spectrum of the sample material. The method further includes using the FWM spectrum to determine a thickness of the sample material, wherein the thickness is a number of layers in the sample material.
Claims17
A system, comprising:
- a single laser output used as an excitation source;
- an optical spectroscopy system configured to perform four-wave mixing (FWM) spectroscopy, and a computer, the computer comprising a processor programmed to:
- measure, via nonlinear optical spectroscopy, a FWM spectrum of a sample material as a function of two or more wavelengths;
- use the FWM spectrum to determine a thickness of the sample material, wherein the thickness is thickness is a number of layers in the sample material.
1 more element
A system, comprising:
- an optical spectroscopy system comprising a single laser output used as an excitation source and modulators configured to perform four-wave mixing (FWM) spectroscopy,
- wherein the FWM spectrum is induced by two or more excitation beams, the modulators apply two different frequencies (f1 and f2) to the excitation beams, and the FWM spectrum is measured on a photodetector by lock-in detection at a difference (f1−f2) or a sum (f1+f2) frequency;
- and
- a computer, the computer comprising a processor programmed to:
- measure, via nonlinear optical spectroscopy, a FWM spectrum of a sample material as a function of two or more wavelengths;
- use the FWM spectrum to determine a thickness of the sample material, wherein the thickness is a number of layers in the sample material.
3 more elements
A method for determining a number of layers of a sample material, comprising:
- directing a single laser output as an excitation source toward the sample material;
- measuring, via nonlinear optical spectroscopy, a four-wave mixing (FWM) spectrum of the sample material as a function of two or more wavelengths;
- and
- using the FWM spectrum to determine a thickness of the sample material, wherein the thickness is a number of layers in the sample material.
1 more element
A method for determining a number of layers of a sample material, comprising:
- modulating two or more excitation beams with two different frequencies (f1 and f2) using modulators configured to perform four-wave mixing (FWM) spectroscopy;
- directing the modulated excitation beams toward the sample material to induce a FWM spectrum;
- measuring the FWM spectrum on a photodetector by lock-in detection at a difference (f1−f2) or a sum (f1+f2) frequency;
- measuring, via nonlinear optical spectroscopy, the FWM spectrum of the sample material as a function of two or more wavelengths;
- and
- using the FWM spectrum to determine a thickness of the sample material, wherein the thickness is a number of layers in the sample material;
- wherein a single laser output is used as an excitation source.
4 more elements
Dependencies are inferred from the claim text.