A Hyperlens-Embedded Solid Immersion Lens for Beam Focusing Beyond the Diffraction Limit

A novel beam focusing device called hyperlens-embedded solid immersion lens (HESIL) is proposed in this letter. In the device, a hyperlens which supports propagating waves with very large wavenumbers is embedded into a super-hemispherical solid immersion lens and a super-resolution focusing spot can be formed at the bottom planar plane of the HESIL. The working principles and characteristics of the device are discussed in detail. Numerical simulations verify that a nano-scale spot with a diameter of 57.5 nm (1/6.5 of the vacuum wavelength
$\lambda_{0}$
) is achieved (the numerical aperture of the objective is 0.45) and the system transmission exceeds 34%, which validates the effectiveness of our proposed device for beam focusing. The device is expected to find numerous applications in high-density near-field optical data storage, nano-photolithography, and so on.