A novel 3D printed focusing probe in scattering-type scanning near-field millimetre & Terahertz wave microscope

Scattering-type scanning near-field microscope has been important to increase the resolution and overcome the limitation of Rayleigh criterion about the wavelength in the far field. Millimetre- (30 - 300GHz) and Terahertz- (300 - 3000GHz) waves provide unique opportunities for the development of novel applications in the active near-field imaging and spectroscopy of microscopic objects. In this paper, we report a novel focusing probe made by 3D printer in the scanning near-field millimetre wave microscope. We analyse the structure and the dielectric properties of this material. The parameters of the tapered tip are simulated in Cassandra which is a three-dimensional full-wave electromagnetic solver developed at the department of information technology (INTEC) at UGent. The experiments are carried out to verify that the 3D printed focusing probes improve the transmission amplitude imaging, the phase images are worse than Teflon probe's phase images because of the inner structure of 3D printed probe which is not homogenous.