Experimental demonstration for scanning near-field optical microscopy using a metal micro-slit probe at millimeter wavelengths

Abstract

Scanning near-field optical microscopy using a slit-type probe is discussed. The slit-type probe has a width of much less than a wavelength, λ, and a length on the order of λ, and thus has high transmission efficiency. Two dimensional near-field images of objects have been constructed using an image reconstruction algorithm based on computerized tomographic imaging. Experiments performed at 60 GHz (λ=5 mm) show that this type of near-field microscopy can achieve a spatial resolution of better than λ/45 for two dimensional imaging. A method for fabricating a submicron width slit probe at the end of an optical fiber is presented for extending this microscopy to optical waves.

Review on Microwave Metamaterial Structures for Near‐Field Imaging

“…Other waveguide structure microscopes based on a scanned aperture were developed by Golosovsky et al [31,32] and Bae et al [33][34][35].…”

Current Status of Infrared Technology

“…To overcome this limit, near-field optical microscope has been proposed and demonstrated. The near-field microscope has been made in the millimeter wave region by using the slit-type probe and the spatial resolution of 83 µm has been attained at the wavelength of 5 mm (14) . Usually the sensitivity is limited by the hole diameter of the probe.…”

Near-Field Microwave Microscopy of Materials Properties

“…The most common technique is to measure reflectivity from a coaxial transmission line terminated (possibly with an air gap) by the sample [26,27,28,29,30,31,32,33]. Variations include the use of waveguides [34,35], waveguides covered by a resonant slit [36,37] and microstrip lines [38] in reflection. Transmission measurements also have been done in the coaxial [31,39] and waveguide [37] geometries.…”

“…Variations include the use of waveguides [34,35], waveguides covered by a resonant slit [36,37] and microstrip lines [38] in reflection. Transmission measurements also have been done in the coaxial [31,39] and waveguide [37] geometries. These techniques have mainly been used to map metallic conductivity or sheet resistance, and dielectric constant.…”