Method and apparatus of atomic force microscope based infrared spectroscopy with controlled probing depth
US11215637B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 28, 2020 |
| Grant date | Jan 4, 2022 |
| Priority date | — |
| Expiry date | Jul 28, 2040 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/0697
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for obtaining optical spectroscopic information about a sub-micron region of a sample with quantitatively controlled depth/volume of the sample subsurface using a scanning probe microscope. With controlled probing depth/volume, the method can separate top surface data from subsurface optical/chemical information. The method can also be applied in liquid suitable for studying biological and chemical samples in their native aqueous environments, as opposed to air. In the method, a depth-controlled spectrum of the surface layer is constructed by illuminating the sample with a beam of infrared radiation and measuring a probe response using at least one of the resonant frequencies of the probe. The surface sensitivity is obtained by limiting the heat diffusion effect of the subsurface so as to confine the signal. The signal confinement is achieved through non-linearity of the acoustic wave with probe, as well as benefits gained by a high modulation frequency of the infrared radiation source at >1 MHz.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.