Scanning near-field microscopy SNOM

Tip-enhanced Raman spectroscopy (TERS) has been developed from the field of scanning near-field microscopy (SNOM), a field that is not directly related to SERS. Howevei one particular important concept of SNOM is also essential for the SERS process the near-field effect. It is common to both SNOM and the electromagnetic enhancement process of SERS and it is the heart of TERS. 

A common approach for imaging near-fields relies on scanning near-field microscopy [SNOM) [51, 52], which offers a lateral resolution, down to tens of nanometers (20-100 nm). However, the measurement involves the insertion of a probe in the immediate vicinity of the object under study, to locally either detect or excite an evanescent field. The presence of the probe generally perturbs the physics of the sample to be characterized and the effective object becomes a complex probe-sample nanosystem, whose physics strongly depends on probe features such as geometry, material, etc. Additionally, producing high quality SNOM probes in a... 

Similar to STM or AFM, scanning-near field microscopy (SNOM) measures the light induced very close to an atomic sized tip. Cinrent SNOM microscopes are either operated in the aperture or scattering mode. The first technique is based on a metal-coated, tapered glass fiber which squeezes the light through an aperture of 50 to 100 nm diameter, while the latter technique exploits the effect of field enhancement when illuminating close to an atomic-sized metal tip. 

Durig U T, Pohl D W and Rohner F 1986 Near-field optical-scanning microscopy J. Appl. Phys. 59 3318 Pohl D W 1991 Scanning near-field optical microscopy (SNOM)/Icfr/. Opt. Electron. Microsc. 12 243... 

More recently, the method of scanning near-field optical microscopy (SNOM) has been applied to LB films of phospholipids and has revealed submicron-domain structures [55-59]. The method involves scanning a fiber-optic tip over a surface in much the same way an AFM tip is scanned over a surface. In principle, other optical experiments could be combined with the SNOM, snch as resonance energy transfer, time-resolved flnorescence, and surface plasmon resonance. It is likely that spectroscopic investigation of snbmicron domains in LB films nsing these principles will be pnrsned extensively. 

Scanning Near-field Optical Microscopy (SNOM)... 

SNOM Scanning near-field optical microscopy (see NSOM)... 

Mechanistic investigations of gas-solid and solid-solid reactions as well as their proper engineering require identifiable crystal surfaces for atomic force microscopy (AFM) and scanning near-field optical microscopy (SNOM) [1,3, 13-15] in combination with X-ray diffraction data, which are the basis of crystal packing analyses [1,3,16-18]. 

Scanning near-field optical microscopy (SNOM) or near-field scanning optical microscopy (NSOM) Shear force microscopy (ShFM) Aperture SNOM (ASNOM) - Transmission ASNOM (T-ASNOM)... 

Fig. 34. dPS volume fraction (J)dPS vs depth z for a 50/50 dPS/PBrxS mixture after annealing for different times at T=180 °C as revealed by TOF-FRES a tA=10 min, b tA=160 min, c tA= 6175 min). In the bottom part, a sketch of the domain structure is shown as revealed from the ion beam and scanning near field optical microscopy (SNOM) results (shaded areas dPS-rich domains white areas dPS-poor domains). From Straub et al. [153]... 

Among the various techniques, we shall only discuss STM, scanning force microscopy (SFM or AFM), and scanning near-field optical microscopy (SNOM or NSOM), as those can well be considered the most prominent members of the SPM family. Among the three, we shall further focus on SFM, as most of the work done on polymers has indeed made use of this method. However, a brief note on STM and SNOM seems appropriate. 

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