Scanning exciton microscopy and single-molecule resolution and detection (Keynote Paper)

Raoul Kopelman*, Weihong Tan, Aaron Lewis, Klony Lieberman

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

Subwavelength light sources have been constructed with the aid of luminescent and exciton transporting materials. These EXCITOR (exciton transmitted optical radiation) sources produce evanescent luminescence and can be used as scanning, light emitting tips of nanometer dimensions. They can also be used as scanning exciton donor tips. The theoretical resolution limit of this kind of near-field optical microscopy is on the atomic or molecular scale. The detection limit is a single molecule, but in contrast to other single molecule detection methods, this single molecule could be identified spatially as well as spectrally. Experimental examples of such an EXCITOR tip consist of gold or aluminum coated glass micropipettes with active crystal tips (anthracene, tetracene, perylene, etc.). Design considerations involve optical, excitonic, photochemical and mechanical properties of the luminescent point source. As it is scanned over a sample, it senses a variety of perturbations such as quenching or external heavy atom effects. It can also actively excite a luminescent probe. The latter process can be non-radiative (e.g., Forster) or may involve absorption and re-emission of evanescent luminescence. Spatially coupled emission and absorption processes are of both theoretical and practical interest. They open a way for reducing by many orders of magnitude the number of photons required to excite a single, isolated chromophore. Molecular exiton microscopy allows extention of near-field microscopy beyond the 50 nm limit already achieved and, thus, permits a new frontier of resolution with light based on the limits of energy transfer measurements. In essence, then, the goal of this research is a spectrally sensitive light microscope that will have the capability to zoom non-destructively and in air from the limits of resolution of lens-based confocal light microscopy (200 nm) to molecular dimensions of 1 nm.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
PublisherPubl by Int Soc for Optical Engineering
Pages96-101
Number of pages6
ISBN (Print)0819405256
StatePublished - 1991
Externally publishedYes
EventOptical Methods for Ultrasensitive Detection and Analysis: Techniques and Applications - Los Angeles, CA, USA
Duration: 21 Jan 199123 Jan 1991

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1435
ISSN (Print)0277-786X

Conference

ConferenceOptical Methods for Ultrasensitive Detection and Analysis: Techniques and Applications
CityLos Angeles, CA, USA
Period21/01/9123/01/91

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