Pump probe cross correlation fluorescence frequency domain microscope and microscopy
US5814820A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 1996 |
| Grant date | Sep 29, 1998 |
| Priority date | — |
| Expiry date | Feb 9, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/16
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A scanning fluorescence lifetime microscope measures modulation and phase in fluorescence emission stimulated by spatially overlapped pump and probe beams operating at different frequencies. A pump laser modulated at a first frequency is focused onto a diffraction limited spot to excite a fluorescent sample under study. Simultaneously, a probe laser modulated at a second frequency is focused onto the same spot to induce a stimulated fluorescence emission in response to the optically combined output of the pump and probe laser light. Fluorescence emitted from the sample produces a cross-correlation signal which is dependent upon the spatial overlapping of the pump and probe beams at the focal point thereby producing a beneficial axial sectioning effect. Choosing a small differency frequency between the modulation of the first and second laser sources produces a low frequency cross correlation signal even when the modulation frequencies of the pump and probe lasers are very high. A signal processor obtains modulation and phase information from the low frequency cross correlation fluorescence signal allowing monitoring of even ultrafast fluorescence phenomena induced by high frequency…
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