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We present the photonic printing that can display different color images depending on the optical polarization of incident light. The dynamic selection among different images becomes possible by using anisotropic Fabry-Perot resonators that incorporate a layer of liquid crystal molecules aligned by directional molecular registration (DMR) as polarization-dependent color pixels. Using the new device platform, we demonstrate a prototype of an anticounterfeiting label with inherent anti-replicability that results from the molecular-level origin of security images. In addition, this concept is extended to polarization-selective holography. Our molecular-level approach enables to develop a new class of security labels and holographic storage media.

Waveguide-integrated plasmonics is a growing field with many innovative concepts and demonstrated devices in the visible and near-infrared. Here, we extend this body of work to the mid-infrared for the application of surface-enhanced infrared absorption (SEIRA), a spectroscopic method to probe molecular vibrations in small volumes and thin films. Built atop a silicon-on-insulator (SOI) waveguide platform, two key plasmonic structures useful for SEIRA are examined using computational modeling: gold nanorods and coaxial nanoapertures. We find resonance dips of 90% in near diffraction-limited areas due to arrays of our structures and up to 50% from a single resonator. Each of the structures is evaluated using the simulated SEIRA signal from poly(methyl methacrylate) and an octadecanethiol self-assembled monolayer. The platforms we present allow for a compact, on-chip SEIRA sensing system with highly efficient waveguide coupling in the mid-IR.

The scattering of electromagnetic waves by periodic layered media plays a crucial role in many applications in optics and photonics, in particular in nanoplasmonics for topics as diverse as extraordinary optical transmission, photonic crystals, metamaterials, and surface plasmon resonance biosensing. With these applications in mind, we focus on surface plasmon resonances excited in the context of insulator-metal structures with a periodic, corrugated interface. The object of this contribution is to study the geometric limits required to generate these fundamentally important phenomena. For this we use the robust, rapid, and highly accurate field expansions method to investigate these delicate phenomena and demonstrate how very small perturbations (e.g., a 5 nm deviation on a 530 nm period grating) can generate strong (in this instance 20%) plasmonic absorption, and vanishingly small perturbations (e.g., a 1 nm deviation on a 530 nm period grating) can generate nontrivial (in this instance 1%) plasmonic absorption.

The scattering of time-harmonic linear waves by periodic media arises in a wide array of applications from materials science and nondestructive testing to remote sensing and oceanography. In this work we have in mind applications in optics, more specifically plasmonics, and the surface plasmon polaritons that are at the heart of remarkable phenomena such as extraordinary optical transmission, surface-enhanced Raman scattering, and surface plasmon resonance biosensing. In this paper we develop robust, highly accurate, and extremely rapid numerical solvers for approximating solutions to grating scattering problems in the frequency regime where these are commonly used. For piecewise-constant dielectric constants, which are commonplace in these applications, surface formulations are clearly advantaged as they posit unknowns supported solely at the material interfaces. The algorithms we develop here are high-order perturbation of surfaces methods and generalize previous approaches to take advantage of the fact that these algorithms can be significantly accelerated when some or all of the interfaces are trivial (flat). More specifically, for configurations with one nontrivial interface (and one trivial interface) we describe an algorithm that has the same computational complexity as a two-layer solver. With numerical simulations and comparisons with experimental data, we demonstrate the speed, accuracy, and applicability of our new algorithms.

This paper investigates the millimeter electromagnetic waves passing through a metal nanogap. Based upon the study of a perfect electrical conductor model, we show that the electric field enhancement inside the gap saturates as the gap size approaches zero, and the ultimate enhancement strength is inversely proportional to the thickness of the metal film. In addition, no significant enhancement can be gained by decreasing the gap size further if the aspect ratio between the dimensions of the underlying geometric structure exceeds approximately 100.

In this paper we demonstrate that rigorous high-order perturbation of surfaces (HOPS) methods coupled with analytic continuation mechanisms are particularly well-suited for the assessment and design of nanoscale devices (e.g., biosensors) that operate based on surface plasmon resonances generated through the interaction of light with a periodic (metallic) grating. In this connection we explain that the characteristics of the latter are perfectly aligned with the optimal domain of applicability of HOPS schemes, as these procedures can be shown to be the methods of choice for low to moderate wavelengths of radiation and grating roughness that is representable by a few (e.g., tens of) Fourier coefficients. We argue that, in this context, the method can, for instance, produce full and precise reflectivity maps in computational times that are orders of magnitude faster than those of alternative numerical schemes (e.g., the popular "C-method," finite differences, integral equations or finite elements). In this initial study we concentrate on the description of the basic principles that underlie the solution scheme, including those that relate to analytic continuation procedures. Within this framework, we explain how, in spite of conventional wisdom to the contrary, the resulting perturbative techniques can provide a most valuable tool for practical investigations in plasmonics. We demonstrate this with some examples that have been previously discussed in the literature (including treatments of the reflectivity and band gap structure of some simple geometries) and extend this to demonstrate the wider applicability of the proposed approach.

We propose a method of optical data storage that exploits the small dimensions of metallic nano-particles and/or nano-structures to achieve high storage densities. The resonant behavior of these particles (both individually and in small clusters) in the presence of ultraviolet, visible, and near-infrared light may be used to retrieve pre-recorded information by far-field spectroscopic optical detection. In plasmonic data storage, a very short (approximately few femtoseconds) laser pulse is focused to a diffraction-limited spot over a small region of an optical disk containing metallic nano-structures. The digital data stored in each bit-cell, comprising multiple bits of information, modifies the spectrum of the incident light pulse. This spectrum is subsequently detected, upon reflection/transmission, with the aid of an optical spectrum analyzer. We present theoretical as well as preliminary experimental results that confirm the potential of plasmonic nano-structures for high-density optical data storage applications.

Free-space-based channelized dynamic spectral equalizers are theoretically investigated by solving the temporal-frequency-dependent power-coupling integral for commonly used active device technologies: liquid-crystal modulators, tilting micromirror arrays, and deformable gratings. Channel-filter characteristics, such as bandwidth and interchannel transition, are found to depend on the different attenuation mechanisms provided by the active devices. Such information is required for choosing the proper device parameters in designing channel equalizers and similar free-space spatially dispersed subsystems.