Experimental study of Terahertz superfocusing with super-oscillation phenomenon

We experimentally study the superfocusing performance of the Terahertz super-oscillation lens (TSOL). The TSOL which generates Terahertz super-oscillation light field in the focal plane is composed of a Terahertz aspheric lens and an optimized binary 0-pi. phase device. For a proofed TSOL (numerical aperture NA = 0.4614) @ working wavelength of lambda = 119 mu m, the FWHM of the super-oscillation spot similar to 0.80 lambda. is about 0.70 times of the Airy spot. Theoretical simulation is performed to validate the confocal scanning imaging resolution enhancement of the TSOL and the imaging resolution of the TSOL is about 0.85 times of the Rayleigh criterion. This study has potential applications in the terahertz super-resolution imaging.