Ultra-Enhanced Lasing Effect of Plasmonic Lens Structured with Elliptical Nanopinholes Distributed in Variant Periods

Abstract

A plasmonic lens constructed with elliptical pinholes ranging from micron to nanoscales distributed in variant periods along the radial direction was presented. Our computational numerical calculation results demonstrated that an ultra-enhanced lasing effect exists while linear polarized plane wave illuminates and passes through the pinholes. The lasing effect can extend the longitudinal focal region and reach as long as 12 µm along the propagation direction. Benefiting from the lasing effect, depth of focus with extraordinarily elongated length (three orders of magnitude in comparison to that of the conventional microlenses) is generated accordingly. Undoubtedly, it may be helpful for practical applications such as data storage, photolithography, and bioimaging.

Investigation of Metallic Elliptical Nano-Pinholes Structure-Based Plasmonic Lenses: From Design to Testing

“…It is in accordance with our previous theoretical calculation and analyses reported in Ref. [6]. 1.0λ…”

“…Many types of plasmonic lenses appeared subsequently such as metallic cone-shaped waveguide [1,2], width modulation-based lenses [3][4][5], elliptical nanopinhole lens [6,7], single circular ring-based lens [8][9][10][11], circular pinholes lens [12], nanowaveguide focusing [13], radial polarization-based circular grating lens [14,15], photon sieve [16], and polarization-based elliptical nanohole arrays [17,18]. All of the reported structures have functions and advantages of focusing surface plasmons, superfocusing within the range of micron-scale along propagation direction and spatial resolution beyond diffraction limit, and extraordinary transmission.…”

“…Ag thin film-based elliptical nano-pinhole structured plasmonic lens was theoretically studied by means of computational numerical calculation on the basis of finite-difference time-domain (FDTD) algorithm in Ref. [6] before.…”

“…The formula was deduced in terms of optical path difference λ by the relationship of f 2 +r n 2 =(f+nλ) 2 , where n is integer number of rings, f is focal length, and r n is n th radius of the rings. Advantage of the elliptical pinholes in comparison to circular grating metallic structure is that the pinhole lens has elongated focal length and extended depth of focus (DOF) [6]. The focal region is formed by interference between the cavity mode-coupled SPPs wave and diffraction wavelets passing through the rings designed as the metallic dielectric-air (MDA) waveguides formed by the Au films as well as their clad dielectric layers.…”

Nanofabrication and Characterization of Plasmonic Structures

“…8 (a) [17]. The plasmonic lens is composed of elliptical pinholes with different sizes distributed in different rings with variant periods.…”