Experimental observation of flat focusing mirror based on photonic jet effect

Igor V Minin,Cheng-Yang Liu,Oleg V Minin,Kestutis Staliunas,Yu-Chih Yang

doi:10.1038/s41598-020-65292-7

Igor V Minin, Cheng-Yang Liu + Show 3 more

Open Access

https://doi.org/10.1038/s41598-020-65292-7

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Abstract

In this work, we experimentally demonstrate that a thin rectangle dielectric-metal structure can have a function of a flat focusing mirror based on photonic jet effect in reflection mode. Using polydimethylsiloxane (PDMS) rectangle with size length of 10 μm and wavelength-scale thickness of 1 μm on the top of a silicon wafer, we have built a flat mirror which focuses an incident beam at the focal length changing from 1.38 μm to 11.67 μm upon tuning the beam incidence angle from 30° to 75°. The focusing properties of such a mirror persist in the wavelength range of 405 nm to 671 nm. Our approach can be extended to realize other optical functionalities by properly controlling rectangle dimensions and materials. This flat focusing mirror is able to guide the incident beam in free space without perceptible diffraction at the distance equal to the photonic jet length and suitable for small-scale photonic circuits.

Highlights

In this work, we experimentally demonstrate that a thin rectangle dielectric-metal structure can have a function of a flat focusing mirror based on photonic jet effect in reflection mode
The capabilities of localized electromagnetic field using mesoscale 3D dielectric cuboid placed on flat surface and working in reflection mode are studied under plane-wave illumination
The capability to produce photonic jet (PJ) in reflection mode is numerically studied using dielectric thin rectangle (TR) illuminated by laser beam under different oblique angles

Summary

Introduction

We experimentally demonstrate that a thin rectangle dielectric-metal structure can have a function of a flat focusing mirror based on photonic jet effect in reflection mode. It could be noted that a flat focusing lens based on a flat chirped dielectric mirror cannot focus a radiation at normal incidence[9] Another approach to building a FFM is based on the photonic jet (PJ) effect[10,11,12,13] in reflection mode. In this case, the dielectric cuboid is illuminated with a plane wave and a PJ (the beam focus) appears close to the cuboid surface from the opposite direction of the incident electromagnetic field[14,15]. The PJ performance is directly observed from dielectric TR under oblique incidence

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