Method and apparatus for infrared scattering scanning near-field optical microscopy
US9372154B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 2, 2014 |
| Grant date | Jun 21, 2016 |
| Priority date | — |
| Expiry date | Dec 25, 2034 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01Q60/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This invention involves measurement of optical properties of materials with sub-micron spatial resolution through infrared scattering scanning near field optical microscopy (s-SNOM). Specifically, the current invention provides substantial improvements over the prior art by achieving high signal to noise, high measurement speed and high accuracy of optical amplitude and phase. Additionally, it some embodiments, it eliminates the need for an in situ reference to calculate wavelength dependent spectra of optical phase, or absorption spectra. These goals are achieved via improved asymmetric interferometry where the near-field scattered light is interfered with a reference beam in an interferometer. The invention achieves dramatic improvements in background rejection by arranging a reference beam that is much more intense than the background scattered radiation. Combined with frequency selective demodulation techniques, the near-field scattered light can be efficiently and accurately discriminated from background scattered light. These goals are achieved via a range of improvements including a large dynamic range detector, careful control of relative beam intensities, and high bandwidt…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.