Method and apparatus for evanescent filed measuring of particle-solid separation
US7234343B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 2004 |
| Grant date | Jun 26, 2007 |
| Priority date | — |
| Expiry date | Sep 27, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01Q20/02
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Evanescent wave scattering by a scanning probe in a scanning probe microscope is utilized to determine and monitor separation between a scanning probe and a sample. A laser light is totally internally reflected at the interface between a more optically dense (incident) medium and less optically dense (transmitting) medium, exciting a decaying evanescent field in the less optically dense medium. A scanning probe, such as a colloidal probe, is dipped into the evanescent field, which scatters off the scanning probe. The portion of the scattered field propagates back into the incident medium and is then detected by a detector. A dependency between the intensity of the scattered evanescent field and the separation between the probe and the incident medium was measured and used in determining the separation. This dependency of intensity is used to prepare images or maps of interfaces. A particular application of determining the separation between the probe and the sample in an atomic force microscope is disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.