Surface–plasmon microscopy

摘要: The imaging of low-contrast samples is a challenging task for optical measuring techniques, especially if high lateral resolution also required. For example, heterogeneously organized lipid monolayer transferred from the water surface to solid substrate1 still needs an additional contrast enhancement mechanism (the solubility difference fluorescing chromophore incorporated between fluid and crystalline domains monolayer) be visualized by fluorescence microscopy. mere thickness or index different regions not sufficient use either phase Nomarsky microscopy2 more recently developed Isoscope ellipsometer3. Here we describe new microscope technique—surface plasmon microscopy (SPM)— which offers superior without loss spatial using polariton (PSP) fields instead normal light as illumination source. Such electromagnetic modes travel along metal–dielectric interface bound, non-radiative wave, with its field amplitudes decaying exponentially perpen-dicular interface. Although photons can converted into PSPs means coupler (a grating prism in many cases) this 'light' differs considerably plane electromagneticwaves4. are characterized first, pronounced disper-sion (energy momentum linearly related speed light); second, intensity that concentrated at strongly enhanced there. Some these properties make sensitive measure interfaces ultrathin films. If used illuminate interfacial structures microscopy, obtained owing sensitivity resonance coupling (for example) small variations thin dielectric coatings.