Accession Number : ADP008304

Title :   Fluorescence Excitation of Single Molecules,

Corporate Author : BORDEAUX-1 UNIV TALENCE (FRANCE)

Personal Author(s) : Orrit, M. ; Bernard, J.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : A few years ago, many people would have deemed the optical observation of single molecules nearly impossible. Yet, new experiments at room and at liquid helium temperatures have started to remove this psychological barrier. Several applications to trace detection and sensing, to spectroscopy of localized neighborhoods and to optical addressing of local spots in solids may now be envisioned. The purpose of this presentation is to show that single molecules can be studied at helium temperatures by means of a fairly simple setup, at least in the very favorable case of pentacene in terphenyl crystal. We thus hope to stimulate further work either on this model system or on more difficult ones with more sophisticated detection methods. The main difficulties in dealing with single molecules arise from the weakness of the signal. During the long accumulation times, the molecular resonance frequency must be fixed: As hole burning and spectral diffusion will interrupt the accumulation, the host-guest couple should be chosen so that both processes are minimal.

Descriptors :   *MOLECULES, *FLUORESCENCE, *EXCITATION, ACCUMULATION, ADDRESSING, BARRIERS, CRYSTALS, DETECTION, DIFFUSION, FREQUENCY, HELIUM, LIQUID HELIUM, LIQUIDS, MODELS, OBSERVATION, RESONANCE, SIGNALS, SOLIDS, SPECTROSCOPY, TEMPERATURE, WORK, OPTICS, ABSORPTION, FIBERS, MOLECULAR SPECTROSCOPY.

Subject Categories : Optics
      Crystallography
      Inorganic Chemistry
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE