Optical quantification of interfacial charge states

Patent metadata

Field	Value
Publication number	US-10514585-B2
Application number	US-201916299383-A
Country	US
Kind code	B2
Filing date	Mar 12, 2019
Priority date	Dec 8, 2016
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

An apparatus for probing an interface via second harmonic generation (SHG) spectroscopy is provided. The apparatus comprises a sample cell comprising a noncentrosymmetric material having a selected orientation angle with respect to a reference axis; optics configured to illuminate an interface formed between the noncentrosymmetric material and a different material, or formed between two different materials and disposed over the noncentrosymmetric material, with light having a frequency ω under conditions to generate a second harmonic generation (SHG) signal having frequency 2ω; a detector configured to detect the SHG signal, the SHG signal comprising a bulk second harmonic signal from the noncentrosymmetric material and an interfacial second harmonic signal from the interface; and a device comprising a processor and a computer-readable medium operably coupled to the processor, the computer-readable medium having computer-readable instructions stored thereon that, when executed by the processor, cause the apparatus to: illuminate the interface to generate the SHG signal and detect the SHG signal.

First claim

What is claimed is:

1. An apparatus for probing an interface via second harmonic generation (SHG) spectroscopy, the apparatus comprising:
(a) a sample cell comprising a noncentrosymmetric material having a selected orientation angle with respect to a reference axis;
(b) optics configured to illuminate an interface formed between the noncentrosymmetric material and a different material, or formed between two different materials and disposed over the noncentrosymmetric material, with light having a frequency ω under conditions to generate a second harmonic generation (SHG) signal having frequency 2ω;
(c) a detector configured to detect the SHG signal, the SHG signal comprising a bulk second harmonic signal from the noncentrosymmetric material and an interfacial second harmonic signal from the interface; and
(d) a device comprising a processor and a computer-readable medium operably coupled to the processor, the computer-readable medium having computer-readable instructions stored thereon that, when executed by the processor, cause the apparatus to
illuminate the interface to generate the SHG signal; and
detect the SHG signal.

2. The apparatus of claim 1 , the computer-readable medium further having computer-readable instructions stored thereon that, when executed by the processor, cause the device to associate the detected SHG signal with an interfacial charge at the interface.

3. The apparatus of claim 2 , wherein associating the detected SHG signal with the interfacial charge is carried out by comparing the detected SHG signal to a SHG signal generated from a reference interface formed between the noncentrosymmetric material and a reference material at the selected orientation angle.

4. The apparatus of claim 3 , wherein the noncentrosymmetric material is α-quartz and the reference material comprises water.

5. The apparatus of claim 4 , wherein the selected orientation angle is 30°.

6. The apparatus of claim 1 , the computer-readable medium further having computer-readable instructions stored thereon that, when executed by the processor, cause the apparatus to repeat the illumination and detection steps at a second, different orientation angle.

7. The apparatus of claim 1 , wherein the sample cell is configured to provide an external reflection geometry.

8. The apparatus of claim 1 , wherein the noncentrosymmetric material is α-quartz.

9. The apparatus of claim 1 , wherein the noncentrosymmetric material is provided as a substrate composed entirely of the noncentrosymmetric material.

10. The apparatus of claim 1 , wherein the noncentrosymmetric material is provided as a film on a supporting substrate.

11. The apparatus of claim 10 , wherein the supporting substrate comprises a centrosymmetric material.

12. The apparatus of claim 1 , wherein the different material, or one of the two different materials, comprises water.

13. The apparatus of claim 1 , wherein the interface is the interface formed between the two different materials.

14. The apparatus of claim 13 , wherein one of the two different materials comprises water.

15. The apparatus of claim 13 wherein one of the two different materials is a film formed on the noncentrosymmetric material.

16. The apparatus of claim 15 , wherein the other of the two different materials comprises water.

Assignees

• Univ Northwestern
• Battelle Memorial Institute
• Univ Columbia

Inventors

• Geiger Franz M
• Ohno Paul E
• Wang hong-fei
• Eisenthal Kenneth B

Classifications

• G01N21/636 Primary

  using an arrangement of pump beam and probe beam; using the measurement of optical non-linear properties; (non-linear optics per se G02F1/35) · CPC title

• G02F1/35

  Non-linear optics · CPC title

• G02F1/37

  for second-harmonic generation {(G02F1/3532 takes precedence)} · CPC title

• G02F1/355

  characterised by the materials used · CPC title

• G01N21/8422

  Investigating thin films, e.g. matrix isolation method · CPC title