Nonlinear effects in modulated photonic structures: metal-dielectric and graphene-based nanostructures and random nonlinear media
Abstract
We propose to conduct state-of-the-art experimental studies in sub-wavelength, nano-structured photonic materials, in order to study the feasibility to enhance and manage simultaneously linear and nonlinear optical effects. The peculiarities of these modulated micro structures have emerged as being pivotal for applications in the field of nanotechnology and all-optical devices. We will focus our attention on nonlinear phenomena in a variety of metal-dielectric or metal-semiconductor nano-structures that display either: (i) enhanced field penetration inside the bulk metal, or (ii) plasmonic effects, which tend to enhance field amplitudes near the surface of the metal, and make possible the exploitation of the evanescent portion of the field. The main goal is to study and prove enhancement of pump absorption and nonlinear frequency conversion, such as second (SHG) and third harmonic generation (THG) in several configurations: (i) metal-dielectric lamellar stacks and gratings, but also more complicated 2D structures combining metals and dielectrics. (ii) metal-dielectric and/or semiconductor sub-wavelength modulated structures filled with gain, epsilon-near-zero (ENZ), or other nonlinear material. Our experimental results will be developed in very close relation with the numerical simulations and theoretical study of these structures. Another important portion of this effort will focus on the expansion of our studies about nonlinear effects and their applications in materials with a random size and distribution of anti-parallel orientated nonlinear domains. As we have previously shown, such crystals provide phase matching for frequency conversion processes over wide angular and frequency bandwidths without need for angular or temperature tuning and can generate second harmonic signal in a direction transverse to the propagation beam (TSHG). We have implemented the single-shot autocorrelation technique based on the TSHG trace monitoring and analysis for the analysis of 200fs pulses. This measurement, combined with the known dispersion of the SBN crystal, makes possible the determination of the pulse duration and chirp parameter of the incident pulse. This technique permits a real-time analysis of the pulse evolution and facilitates fast in-situ correction of pulse chirp acquired in the propagation through an optical system. Here we propose to extend this method to: (i) characterization of pulses shorter that 30 fs and different wavelengths in the range of 0.8 and 3 microns; (ii) develop a cross-correlation scheme based of the TSHG method; (iii) design a new experimental configuration for the full-field pulse retrieval (phase effects).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 22, 2018
- Source ID
- W911NF1610563
Entities
People
- Crina Cojocaru
Organizations
- Army Contracting Command
- Polytechnic University of Catalonia
- United States Army