Interference Of Plasmon Polaritons Research Articles

Circular polarization analyzer based on surface plasmon polariton interference.

The determination of chirality of circularly polarized light (CPL) is of great significance to the development of various optical techniques. In this paper, a miniature circular polarization analyzer (CPA) based on surface plasmon polariton (SPP) interference is proposed. The proposed CPA consists of a micron scale long sub-wavelength slit and two groups of spatially arranged periodic sub-wavelength rectangular groove pairs, which are etched in a metal layer. Under the illumination of a CPL with a given chirality, the proposed CPA is capable of forming SPP-mediated interference fringes with different periods in far field. The chirality of CPL can be directly and quantitatively differentiated by the frequency value of the far field SPP-mediated interference fringes. Different from the existing SPP-based CPAs, the proposed CPA can directly image the chirality information in far field, avoiding near-field imaging of the SPP field.

Femtosecond laser-induced spatial-frequency-shifted nanostructures by polarization ellipticity modulation.

We demonstrate a prominent spatial frequency shift (SFS) for the femtosecond laser-induced periodic structures by only changing the polarization ellipticity of the working laser. The nanostructures are fabricated on the surfaces of silicon (Si) and zinc selenide (ZnSe) using elliptically polarized femtosecond laser pulses, with the pulse duration of 35 fs, the central wavelength of 800nm, and the repetition rate of 1kHz. The experimental results show that the red- and blue-shift trends of the SFS are individually represented on silicon and zinc selenide with the increased polarization ellipticity, where low- and high-spatial-frequency nano-ripples are fabricated, respectively. These unique phenomena are explained by using the laser-surface plasmon polariton interference mechanism and the effective medium theory. The proposed nanostructures with regulatable period are further used for creating nano-gratings on silicon which perform chirped characteristics.

Polarization-switchable nanoripples fabricated on a silicon surface by femtosecond-laser-assisted nanopatterning.

The polarization ripples on many materials have been intensively studied and have yielded significant applications such as modulating light fields, building hydrophobic or hydrophilic surfaces, and fabricating tunable thermal sources. It was shown that ripples are closely dependent on the ablation threshold of laser fluence and orientation of laser polarization. Here we demonstrate that laser polarization ellipticity also represents the switching effect on the formation of ripples. Two significantly different damage morphologies, ripples and hollows, are respectively observed below and above the switching value of incident laser polarization ellipticity. Furthermore, it is demonstrated that this ellipticity switching value varies with laser pulse energy and pulse number. These intriguing phenomena are qualitatively explained using a laser-surface plasmon polariton interference mechanism. Finally, we achieve the analogous laser-assisted nanopatterning by using a femtosecond laser beam with spatially inhomogeneous polarization state, demonstrating the application potential of these switchable nanoripples in laser-assisted nanopatterning.

Shift of the surface plasmon polariton interference pattern in symmetrical arc slit structures and its application to Rayleigh metallic particle trapping.

In symmetric nano/micro metal slit structures, interference patterns are produced by counter-propagating surface plasmon polaritons (SPPs) in the the center of structures, which can be employed to improve the resolution of microscopy and surface etching and to realize particle trapping. This paper focuses on the shift of the SPP interference patterns in the symmetric arc slit structures. The excitation models with one incident beam and two incident beams are established and analyzed respectively, and methods to shift the SPP interference patterns via adjusting the tilt angle and initial phase of the excitation beams are compared. The FDTD simulation results show that these methods can precisely shift the SPP interference patterns in the symmetrical arc slits. Compared to the linear slits, the SPP waves arising from arc slits are more strongly focused, resulting in a stronger gradient force. The characteristics of stronger focus and dynamic shifting of the focal spot give the symmetric arc slit structure unique advantages in the capture and transfer of the Rayleigh metallic particle.

Generating a lattice of optical skyrmions

Topological Optics The topological properties of systems can be robust to defects and imperfections. Skyrmions are one such topological entity, which resemble “hedgehog-like” structures. Tsesses et al. controlled the interference of plasmon polaritons on a patterned metallic surface to generate a lattice of optical skyrmions. Such control could potentially optically mimic complex condensed matter systems or help in the development of robust optical communications and circuits. Science , this issue p. [993][1] [1]: /lookup/volpage/361/993?iss=6406

Optical skyrmion lattice in evanescent electromagnetic fields.

Topological defects play a key role in a variety of physical systems, ranging from high-energy to solid-state physics. A skyrmion is a type of topological defect that has shown promise for applications in the fields of magnetic storage and spintronics. We show that optical skyrmion lattices can be generated using evanescent electromagnetic fields and demonstrate this using surface plasmon polaritons, imaged by phase-resolved near-field optical microscopy. We show how the optical skyrmion lattice exhibits robustness to imperfections while the topological domain walls in the lattice can be continuously tuned, changing the spatial structure of the skyrmions from bubble type to Néel type. Extending the generation of skyrmions to photonic systems provides various possibilities for applications in optical information processing, transfer, and storage.

2D surface optical lattice formed by plasmon polaritons with application to nanometer-scale molecular deposition

Surface plasmon polaritons, due to their tight spatial confinement and high local intensity, hold great promises in nanofabrication which is beyond the diffraction limit of conventional lithography. Here, we demonstrate theoretically the 2D surface optical lattices based on the surface plasmon polariton interference field, and the potential application to nanometer-scale molecular deposition. We present the different topologies of lattices generated by simple configurations on the substrate. By explicit theoretical derivations, we explain their formation and characteristics including field distribution, periodicity and phase dependence. We conclude that the topologies can not only possess a high stability, but also be dynamically manipulated via changing the polarization of the excitation laser. Nanometer-scale molecular deposition is simulated with these 2D lattices and discussed for improving the deposition resolution. The periodic lattice point with a width resolution of 33.2 nm can be obtained when the fullerene molecular beam is well-collimated. Our study can offer a superior alternative method to fabricate the spatially complicated 2D nanostructures, with the deposition array pitch serving as a reference standard for accurate and traceable metrology of the SI length standard.

Direction-tunable enhanced emission from a subwavelength metallic double-nanoslit structure.

Controlling light emission out of subwavelength nanoslit/aperture structures is of great important for highly integrated photonic circuits. Here we propose a new method to achieve direction-tunable emission based on a compact metallic microcavity with double nanoslit. Our method combines the principles of Young's interference and surface plasmon polaritons interference. We show that the direction of the far-field beam can be controlled over a wide range of angles by manipulating the frequency and relative phase of light arriving at the two slits, which holds promise for applications in the ultracompact optoelectronic devices.

Four-Port Polarization and Topological Charge Controlled Directional Plasmonic Coupler

In this letter, a four-port directional plasmonic coupler based on excited surface plasmon polariton interference is proposed, which is capable of coupling surface wave into different directions according to polarization directions and topological charges of incident light. In addition, it also acts as a light detector for both polarization and phase twist determination. It is believed that the directional plasmonic coupler will be potential in future plasmonic circuit designs and applications.

Period reduction lithography in normal UV range with surface plasmon polaritons interference and hyperbolic metamaterial multilayer structure

A plasmonic lithography method is proposed to generate a large-area, period-reduced, subwavelength one-dimensional grating pattern. It is demonstrated with a surface plasmon polaritons interference effect and a hyperbolic metamaterial multilayer structure by UV radiation at 405 nm wavelength. Photoresist patterns of 1.5 × 1.5 cm2 area with 350 nm period and 100 nm linewidth were fabricated on polyethylene terephthalate films by using a 700-nm-period Al grating mask and exposed to a transverse magnetic polarized laser. The proposed lithography approach provides a cost-effective and less laborious pathway for the fabrication of large-area periodic nano-patterns.

Self-imaging confirmed in plasmonic channel waveguides at visible wavelengths

We experimentally confirm self-imaging induced by multi-mode interference of plasmon polaritons in a channel waveguide at visible wavelengths. A designed plasmonic channel waveguide, fabricated as three structural segments at two different channel depths, operates as a single- and multi-mode waveguide. Illuminated by incident light of wavelength 635 nm, the channel plasmon polaritons propagate towards the output port if the length of the multi-mode waveguide is equivalent to twice the beat length for multi-mode interference. If the length of the multi-mode waveguide is equivalent to the beat length, only a few of these plasmon polaritons propagate to the output port as most of them are reflected at the far end of the multi-mode segment of the waveguide. Experimental results enable a clear characterization of self-imaging induced by the multi-mode interference of channel plasmon polaritons.

248 nm imaging photolithography assisted by surface plasmon polariton interference

A new photolithography technique for 248 nm based on the interference of surface plasmon waves is proposed and demonstrated by using computer simulations. The basic structure consists of surface plasmon polariton (SPP) interference mask and multi-layer film superlens. Using the amplification effect of superlens on evanescent wave, the near field SPP interference pattern is imaged to the far field, and then is exposed on photo resist (PR). The simulation results based on finite difference time domain (FDTD) method show that the full width at half maximum (FWHM) of the interference pattern is about 19 nm when the p-polarization light from 248 nm source is vertically incident to the structure. Meanwhile, the focal depth is 150 nm for negative PR and 60 nm for positive PR, which is much greater than that in usual SPP photolithography.

Nanometer-scale molecular deposition using the surface Plasmon polariton interference field on a metal film

We explore the possibility of using the surface plasmon polariton interference field to deposit neutral molecules onto a silver film perforated with two double-slits. The Monte Carlo simulated results show that the deposited molecular pattern is the periodic line array with a width resolution of ∼10 nm and a period of 530 nm when the molecular beam is well-collimated. Dependences of the deposition resolution on the system parameters, the potential applications and improvements are also discussed in some detail.

Imaging of surface plasmon polariton interference using phase-sensitive photon scanning tunneling microscope

We report the surface plasmon polariton interference, generated via a ‘buried’ gold grating, and imaged using a phase-sensitive Photon Scanning Tunneling Microscope (PSTM). The phase-resolved PSTM measurement unravels the complex surface plasmon polariton interference fields at the gold-air interface.

背向曝光表面等离子体激元干涉光刻系统中银层超透镜的优化设计

背向曝光表面等离子体激元干涉光刻系统中银层超透镜的优化设计

A practical nanofabrication method: surface plasmon polaritons interference lithography based on backside-exposure technique

For the experiments of surface plasmon polaritons (SPPs) interference lithography based on attenuated total reflection-coupling mode to be done conveniently, we introduce a backside-exposure technique in this paper. The physical mechanisms of SPPs interference with the backside -exposure method are studied and the interference fringes with feature size below 65 nm are experimentally obtained. The technique can be used to fabricate nanostructures conveniently with large area, and avoids the difficulties for seeking high refractive prism and matching fluid.

A tunable unidirectional surface plasmon polaritons source

A new structure to be used as a tunable unidirectional surface plasmon source is introduced. The structure is composed of two silver films, with a nanoslit fabricated in the top Ag film and lying below is a movable Ag film. The field distribution of the structure is investigated by using the finite-difference time-domain(FDTD) method. It is found that the surface plasmon polariton intensity and the splitting ratio change periodically as the bottom film is moved, which is interpreted in terms of surface plasmon polaritons interference in two Fabry-Perot(F-P) cavities. The period obtained by the FDTD agrees well with the F-P interferometer model. The surface plasmon polaritons can be unidirectionally excited with a large intensity splitting ratio.

193 nm interference nanolithography based on SPP

Large-area surface plasmon polariton interference lithography (LSPPIL) is a promising nano-fabrication technique for making periodic nano-patterns. In this paper, for reducing further the feature size of a lithography pattern, we propose to use 193nm illumination wavelength in LSPPIL and replace the silver coating by tungsten. Theoretical analysis and preliminary numerical simulations indicate that 193nm-LSPPIL can produce periodic patterns with a critical dimension as small as 30nm with high contrast and enough long exposure depth. 193nm interference nanolithography based on SPP has the potential to realize the 32nm node periodic nano-structure manufacture.