Novel Materials and Structures for Nonlinear Optics
Abstract
Nonlinear optics is a fascinating branch of science that investigates the light-matter interactions in media, in which the dielectric polarization responds nonlinearly to the electric and/or magnetic field of the light. Although this field has been developing for decades, nonlinear optical materials available to date are still limited by either slow material response time in such phenomena as saturable absorption, photorefractive effect, and thermal nonlinear phenomena, or by relatively low and generally band-limited nonlinear susceptibilities responsible for ultrafast nonlinear processes. While thermally nonlinearities such as thermally induced metal-to-insulator transition in vanadium dioxide and thermo-optical effects in silicon result in refractive index changes of the order of 1, the response time is slow. On the other hand, it is difficult to find any ultrafast nonlinear material that is capable of achieving an ultrafast refractive index change larger than 0.1%. For decades, scientists have been exploring ways of creating materials with a large, fast, and broadband nonlinear response; if found, these would revolutionize nonlinear optics, leading to low-power, compact, and ultra-fast applications of nonlinear optical phenomena. The emergence of metamaterials has a potential to provide a breakthrough in the development of such materials. Indeed, metamaterials were predicted to enable a plethora of novel linear and nonlinear light-matter interactions, including magnetic nonlinear response, backward phase-matching, and the nonlinear mirror, recently demonstrated at microwave frequencies. Since it has already been demonstrated that linear optical properties, such as dielectric permittivity, magnetic permeability, and refractive index of metamaterials can be designed to be positive, negative or even zero at any selected frequency by properly adjusting the dimensions, periodicity and other properties of the so-called metaatoms, it is expected to be possible to largely transform nonlinear properties of metamaterials. At optical frequencies, significant efforts have been devoted to the enhancement of nonlinear optical response using various plasmonic nanostructures, photonic bandgap structures, micro-cavities and resonators. While these first steps demonstrate the feasibility of enhancing the nonlinear response, it is important to note that a majority of these studies essentially exploited strong local field enhancements rather than actual rational design of the nonlinear optical response of the metamaterial. We propose to develop novel physics-based approach to the design of nonlinear metamaterials enabled by the unique electromagnetic properties of meta-atoms. Therefore, we propose the following main directions for our research program: Thrust 1. Nonlinear optical response: origin, limitations, and rational design We propose to develop a comprehensive theoretical framework enabling us to embrace different routes of novel rationally designed photonic metamaterials and structures. In order to do this, we will re-examine existing approaches to the description of nonlinear phenomena in nanostructures to reveal microscopic physical reasons for the limited nonlinear response of existing natural and artificial structures, and develop a path to overcome these limitations. Thrust 2. All-dielectric nonlinear metamaterials Stimulated by recent study of the limited usefulness of plasmonically enhanced structures for nonlinear optics that concluded that these structures, along with other high-Q resonantly enhanced structures, are not as promising as was initially hoped for nonlinear optical processes requiring high efficiency, such as wavelength conversion or switching, we will investigate other degrees of freedom afforded by all-dielectric metamaterials when designing useful nonlinear materials. Thrust 3. Nonlinear interactions in inhomogeneous metamaterials...
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1510146
Entities
People
- Natalia M. Litchinitser
Organizations
- Army Contracting Command
- United States Army
- University at Buffalo