A near-field probe fabrication technique for far-infrared frequencies based on photoconducting antennas is developed. A subwavelength-size field source is accomplished by means of an aperture and protruding high refractive index tip. The near-field probe is tested by using free space traveling electromagnetic pulses with a broadband spectrum in the range of 0.3–1.5 THz. A spatial resolution of ...

The influence of the near-field probe-tip on a model sample consisting one-dimensional apertures is investigated using scanning optical microscopy (SNOM). We use finite-difference time-domain (FDTD) simulations combined with SNOM scans to show that has rather profound effect shape measured transmission intensity profiles. By taking into account perturbations introduced by probe, our newly devel...

We analyze the coupling between conduction and radiative heat transfer in near-field regime two coaxial cylinders separated by a vacuum gap. By solving transport equation steady-state metals or polar materials, we highlight flux saturation mechanism for even without non-local effect. In case of this occurs separation distances range 1–10 nm, which can be experimentally explored.

We have performed scanning gate microscopy (SGM) on graphene field effect transistors (GFET) using a biased metallic nanowire coated with a dielectric layer as a contact mode tip and local top gate. Electrical transport through graphene at various back gate voltages is monitored as a function of tip voltage and tip position. Near the Dirac point, the response of graphene resistance to the tip v...

We have detected sub-wavelength spot sizes in the near-field of a metal tip, which is illuminated with terahertz (THz) pulses. The THz near-field is detected by using electro-optic detection in a (100) oriented GaP crystal. Contrary to conventional electro-optic detection, which uses (110) oriented detection crystals, (100) crystals only allow the detection of THz light, polarized perpendicular...

In this paper, we investigate the effects of the non-singular stress (T stress) on the mode I near-tip fields lbr elastic perfectly plastic pressure-sensitive materials under plane-stress and small-scale yielding conditions. The T stress is the normal stress parallel to the crack faces. The yield criterion for pressure-sensitive materials is described by a linear combination of the effective st...

In this thesis, a new apertureless scanning near-field optical microscope (aSNOM) with the ability to resolve optical properties of surfaces with a lateral resolution better than 50 nm in a broadband infrared (IR) spectrum is described. The high resolution beyond the diffraction limit is achieved by using the sharp tip of an atomic force microscope (AFM) to probe the local electromagnetic field...

A B S TR AC T This paper presents an incremental elastic-plastic finite element solution to the problem of small scale yieldmg near a crack in plane strain for a non-hardening material. Emphasis is placed on the design of finite elements which allow accurate reproduction, m a numerical solution, of the detailed structure of the near crack tip stress and strain fields, as understood from previou...