Exceptional points and enhanced nanoscale sensing with a plasmon-exciton hybrid system

Abstract

Singularities in the spectra of open systems, known as exceptional points (EPs), have been shown to exhibit nontrivial topological properties and enhanced sensitivities. Here, we propose a novel approach to realize the EPs in a plasmon-exciton hybrid system and explore their applications in enhanced nanoscale sensing technology. We consider a plasmon-exciton system composed of a gold nanorod and a monolayer WSe 2 . By controlling the geometric parameters of the nano-hybrid system, we obtain simultaneous coalescence of the resonance frequencies and loss rates of the hybrid system, which is a unique feature of EPs. Numerical simulations show its application in enhanced nanoscale sensing for environmental refractive indices. Our work opens the way to a new class of sensors based on EP-enhanced sensing, with intrinsic nanoscale sensitivity due to the sub-diffraction-limit size of the plasmon-exciton nano-hybrid system.

Microwave Plasmonic Exceptional Points for Enhanced Sensing

“…The complex frequency information is extracted by fitting the transmission spectra using a doublet Lorentz model (see Section S6 in the Supporting Information). [ 39 ] The blue and red dots represent the real and imaginary parts of the complex frequencies when the angular position of the object is changed. It is found that the frequency splitting (real part) and the difference in linewidth (imaginary part) alternate periodically between maximum and minimum.…”

Exceptional points in parity-time symmetric plasmonic Huygens’ metasurfaces

“…While EPs have been extensively investigated in bulky photonic designs [12][13][14][15], their exotic functionalities in nanophotonic non-Hermitian plasmonic systems still remain relatively unexplored. Some recent notable efforts towards this goal are the investigation of active and passive metallic gratings [16,17], plasmonic nanostructures [18][19][20][21], graphene [22,23], and epsilon-near-zero materials [24][25][26][27][28]. An alternative promising class of nanophotonic non-Hermitian scatterers are core-shell plasmonic nanoparticles loaded with active (gain) materials.…”

Anomalous spontaneous emission dynamics at chiral exceptional points

“…A plethora of intriguing effects and exotic phenomena emerge around EPs due to their nontrivial topological properties and the dimensionality reduction, including ultrasensitive sensing [6][7][8][9][10][11][12], laser mode selection [13,14], chiral mode conversion [15][16][17][18], and unidirectional invisibility [19,20]. Harnessing these peculiar features of non-Hermitian degeneracies for building novel devices with unprecedented performance has been experimentally demonstrated in various classical dissipative platforms, ranging from nanophotonics [2,[21][22][23][24][25], acoustics [26] to macroscopic facilities, such as fiber network [27], electric circuits [28] and heat diffusive system [29]. In recent years, great efforts have been dedicated to accessing the quantum EPs by implementing the non-Hermiticity in quantum systems [11,[30][31][32][33][34][35][36][37][38][39][40][41], and investigating the quantum states control through EPs [18, 33-35, 40, 42-44].…”