A Fano-resonance plasmonic assembly for broadband-enhanced coherent anti-Stokes Raman scattering

Abstract

Surface-enhanced coherent anti-Stokes Raman scattering (SECARS) technique has triggered huge interests due to the significant signal enhancement for high-sensitivity detection. Previous SECARS work has tended to focus only on the enhancement effect at a certain combination of frequencies, more suitable for single-frequency CARS. In this work, based on the enhancement factor for broadband SECARS excitation process, a novel Fano resonance plasmonic nanostructure for SECARS is studied. In addition to the 12 orders of magnitude enhancement effect that can be realized under single-frequency CARS, this structure also shows huge enhancement under broadband CARS in a wide wavenumber region, covering most of the fingerprint region. This geometrically-tunable Fano plasmonic nanostructure provides a way to realize broadband-enhanced CARS, with potentials in single-molecular monitoring and high-selectivity biochemical detection.

Application of multi-objective optimization genetic algorithm to design terahertz metamaterials with fano resonances

“…In order to achieve these objectives, a multi-objective optimization mathematical model was developed, with the geometric parameters d and g as the design variables and δ I and Q-factor as the optimization objectives. The mathematical expression for this optimization model is presented as equation (2). Q-factor but at the expense of low δ I .…”

“…The Fano resonance lineshape, which is an asymmetric lineshape, has been observed and studied from the microwave to optical frequency regimes [1][2][3]. When the structural symmetry of the metamaterial is disrupted, a Fano resonance occurs.…”