A near-field scanning optical microscope with a metallic probe tip was developed for detecting localized photons near the surface of fine structure sample. In this is used converting evanescent sample to propagating scattering light wave; scattered detected in far field external condenser optics. During measurement vibrates normal an amplitude ~5 nm at 2.5 kHz, and intensity modulated frequency lock-in detected. This operation permits removal stray-light noise contribution. Experimental...

The optical probe of a scanning near-field microscope is shown to act as point source surface plasmon (SP) polaritons on gold and silver films. Plasmon excitation manifests itself by emission light in the direction SP resonance angle, originating from an area with shape dipole radiation pattern whose extension given decay length. Interaction selected, individual inhomogeneities gives rise characteristic modifications emitted radiation, which provide detailed information about scattering,...

Near-field optical (NFO) microscopes with an auxiliary gap width regulation (shear force, tunneling) may produce images that represent the path of probe rather than properties sample. Experimental and theoretical evidence leads us to conclusion many NFO results reported in past might have been affected or even dominated by resulting artifact. The specifications derived from such for different types used therefore warrant reexamination. We show resolving power aperture microscopes, 30–50 nm,...

An electric field enhanced by a metallic nanoprobe has locally induced coherent anti-Stokes Raman scattering (CARS) of adenine molecules in nanometric DNA network structure. Owing to the third-order nonlinearity, excitation CARS polarization is extremely confined end tip apex, resulting spatial resolution far beyond diffraction limit light. Our tip-enhanced microscope visualized structure at specific vibrational frequency (approximately 1337 cm(-1)) corresponding ring-breathing mode diazole...

The tip-enhanced near-field Raman (TERS) bands of Rhodamine 6G (R6G), that we reported earlier [Chem. Phys. Lett. 2001, 335, 369.], are assigned on the basis density-functional theory (DFT) calculations at 6-311++G(d,p) level. and infrared intensities as well frequencies vibrational modes used for band assignments. These modes, in combination with characterization resonant electronic transitions using time-dependent DFT calculations, predict spectral changes surface-enhanced scatterings R6G....

We demonstrate dynamic imaging of molecular distribution in unstained living cells using Raman scattering. By combining slit-scanning detection and optimizing the excitation wavelength, we imaged distributions cytochrome c, protein beta sheets, lipids HeLa with a temporal resolution 3 minutes. found that 532-nm can be used to generate strong scattering signals suppress autofluorescence typically obscures signals. With this technique, reveal time-resolved c other biomolecules process...

Detecting and identifying single molecules are the ultimate goal of analytic sensitivity. Single molecule detection by surface-enhanced Raman scattering (SM-SERS) depends predominantly on SERS-active metal substrates that usually colloidal silver fractal clusters. However, high chemical reactivity low reproducibility its complicated synthesis with clusters have been serious obstacles to practical applications SERS, particularly for probing biomolecules in extensive physiological...

The problem of blind estimation source signals is to estimate the without knowing characteristics transmission channel. It shown that minimum-variance unbiased estimates can be obtained if and only channel identified blindly. blindly there not more than one Gaussian source. This condition suggests waveform-preserving achieved over a wide range signal processing applications, including those cases in which have identical nonGaussian distributions. constructive proof necessary sufficient...

Near-field Raman imaging of organic molecules is demonstrated by an apertureless near-field scanning optical microscope, the tip which a silver-layer-coated cantilever atomic force microscope (AFM). The virtue enhanced electric field at apex due to surface plasmon polariton excitations enhances scattering cross sections. This phenomenon allows us reveal from images molecular vibrational distributions Rhodamine6G and Crystal Violet beyond diffraction limit light. These vibrations cannot be...

We report on near-field Raman spectra of a single nanocrystal DNA-base adenine molecules using silver-layer-coated apertureless probe tip an atomic force microscope. The tip-enhanced spectrum shows eight bands that are assigned to the normal modes based density-functional theory (DFT) calculations. vibrational frequencies several observed have unambiguously shifted values corresponding bands, conventional surface-enhanced Raman-scattering adsorbed colloidal silver particles. DFT calculations...

The structural colour of the neon tetra is distinguishable from those of, e.g., butterfly wings and bird feathers, because it can change in response to light intensity surrounding environment. This fact clearly indicates variability colour-producing microstructures. It has been known that an iridophore contains a few stacks periodically arranged light-reflecting platelets, which cause multilayer optical interference phenomena. As mechanism variability, Venetian blind model proposed,...

We present a near-field Raman investigation in the subnanometric vicinity of metallic nanotip, where tip-sample distance is precisely controlled by our newly developed time-gated illumination technique. Using this scheme on an isolated carbon nanotube, we have profiled spatial decay evanescent light. also investigated extremely short-ranged chemical and mechanical interactions between metal tip apex molecules adenine sample, which are observable only within tip. The results show with...

Abstract We demonstrate nano‐scale optical analysis of graphene layers by tip‐enhanced near‐field Raman spectroscopy (TERS). In this technique, the spatial resolution ∼30 nm is realized probe which acts as a nano‐light source. From intensity change band silicon generated from probe, we can conveniently estimate edge boundaries and number stacking layers. TERS measurement across layer edges reveals properties material well existence local defects boundaries. The G‐band shows step‐like...

We provide an overview of Fano resonance and plasmon induced transparency (PIT) as well on plasmons coupling in planar structures, we discuss their application sensing enhanced spectroscopy. Metal-insulator-metal (MIM) which are known to support symmetric anti-symmetric surface polaritons (SPPs) arising from the between two SPPs at metal-insulator interfaces, exhibit anticrossing behavior dispersion relations SPP metal/air SPP. Multilayer formed by a metal film high-index dielectric...

High-speed atomic force microscopy (HS-AFM) is an indispensable technique in the field of biology owing to its imaging capability with high spatiotemporal resolution. Furthermore, recent developments established tip-scan stand-alone HS-AFM combined optical microscope, drastically improving versatility. It has considerable potential contribute not only but also various research fields. A great candidate a photoactive material, such as azo-polymer, which important for applications because...

We have developed a scanning near-field optical microscope with an optically trapped metallic particle that has small diameter compared to the wavelength of visible light. In this we employed spot illumination enhance intensity light scattered from probe so could reduce 40 nm. detected slight irregularities surface cover glass near 10-nm depth. Also, observed gold colloidal particles on glass.

Given cumulants of a stationary, perhaps noisy, non-Gaussian r-variate moving average, MA(q) process, identifiability conditions are studied, under which the MA coefficient matrices, input statistics, and order q can be uniquely determined. The selection unique representative from equivalence class corresponding to given cumulant structure involves fewer restrictions than that covariance structure. Two algorithms derived for estimating (possibly) nonminimum-phase matrices.< <ETX...

In situ measurement of tip-enhanced near-field Raman spectra an isolated single-wall carbon nanotube (SWNT) bundle has been demonstrated by applying a uniaxial pressure up to ∼2 GPa the via metal-coated atomic force microscope tip. We investigated dependences frequencies and intensity radial breathing mode bands, D-band G-band, which were related deformation SWNTs caused tip pressure.

Temporal fluctuations of spectral shapes have been observed in tip-enhanced Raman scattering (TERS) spectra adenine molecules. The TERS a nanocrystalline cluster molecules showed distinct temporal changes including peak frequencies and intensities extraordinary enhancements several peaks. fluctuating signals originate primarily from the first layer 5 nm thick cluster. possible origin is attributed to molecular orientation under metal-coated tip, which responsible for changing adsorption...