TUNNEL NEAR-FIELD OPTICAL MICROSCOPY - TNOM-2

Light emitted from the aperture of a near-field optical probe in the c lose vicinity of a dielectric object propagates in classically ''forbi dden'' as well as ''allowed'' directions; the two zones are separated by the critical angle for total internal reflection. The new ''tunnel' ' near-field optical microscopy (TNOM) technique makes use of forbidde n and allowed radiation, in contrast to standard scanning near-field o ptical microscopy (SNOM or NSOM), which records only the allowed light . Scan images obtained with allowed and forbidden light are complement ary to some extent; the latter, however, provide high contrast and res olution even in situations in which standard SNOM/NSOM shows little or no contrast. The influence of topography on image formation is analyz ed and discussed.