scholarly journals Observation of miniaturized bound states in the continuum with ultra-high quality factors

2021 ◽  
Author(s):  
Zihao Chen ◽  
Xuefan Yin ◽  
Jicheng Jin ◽  
Zhao Zheng ◽  
Zixuan Zhang ◽  
...  
Keyword(s):  
Bound States ◽  
Photonic Band Gap ◽  
Light Trapping ◽  
Vertical Direction ◽  
Three Dimensions ◽  
Quality Factors ◽  
High Quality ◽  
Potential Applications ◽  
On Chip ◽  
The Continuum

Abstract Light trapping is a constant pursuit in photonics because of its importance in science and technology. Many mechanisms have been explored, including the use of mirrors made of materials or structures that forbid outgoing waves, and bound states in the continuum that are mirror-less but based on topology. Here we report a compound method, combing mirrors and bound states in the continuum in an optimized way, to achieve a class of on-chip optical cavities that have high quality factors and small modal volumes. Specifically, light is trapped in the transverse direction by the photonic band gap of the lateral hetero-structure and confined in the vertical direction by the constellation of multiple bound states in the continuum. As a result, unlike most bound states in the continuum found in photonic crystal slabs that are de-localized Bloch modes, we achieve light-trapping in all three dimensions and experimentally demonstrate quality factors as high as Q = 1.09×106 and modal volumes as low as V = 3.56 μm3 in the telecommunication regime. We further prove the robustness of our method through the statistical study of multiple fabricated devices. Our work provides a new method of light trapping, which can find potential applications in photonic integration, nonlinear optics and quantum computing.

scholarly journals High Quality-Factor Dual-Band Fano Resonances Induced by Bound States in The Continuum Using A Planar Nanohole Slab

2021 ◽  
Author(s):  
Tian Sang ◽  
Qing Mi ◽  
Yao Pei ◽  
Chaoyu Yang ◽  
Shi Li ◽  
...  
Keyword(s):  
Bound States ◽  
Near Field ◽  
Dual Band ◽  
Q Factor ◽  
Fano Resonances ◽  
High Quality ◽  
Potential Applications ◽  
Q Factors ◽  
Symmetry Protected ◽  
The Continuum

Abstract In photonics, it is essential to achieve high quality (Q)-factor resonances to enhance light-mater interactions for improving performances of optical devices. Herein, we demonstrate that high Q-factor dual-band Fano resonances can be achieved by using a planar nanohole slab (PNS) based on the excitation of bound states in the continuum (BICs). By shrinking or expanding the tetramerized holes of the superlattice of the PNS, symmetry-protected BICs can be excited and the locations of Fano resonances as well as their Q-factors can be flexibly tuned. Physical mechanisms for the dual-band Fano resonances can be interpreted as the resonant couplings between the electric-toroidal dipoles or the magnetic-toroidal dipoles based on the far-field multiple decompositions and the near-field distributions of the superlattice. The dual-band Fano resonances of the PNS possess polarization independent feature, they can be survived even the geometric parameters of the PNS are significantly altered, making them more suitable for potential applications.

scholarly journals High-quality-factor dual-band Fano resonances induced by dual bound states in the continuum using a planar nanohole slab

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Qing Mi ◽  
Tian Sang ◽  
Yao Pei ◽  
Chaoyu Yang ◽  
Shi Li ◽  
...  
Keyword(s):  
Bound States ◽  
Near Field ◽  
Dual Band ◽  
Q Factor ◽  
Fano Resonances ◽  
High Quality ◽  
Dual Bound ◽  
Potential Applications ◽  
Q Factors ◽  
The Continuum

AbstractIn photonics, it is essential to achieve high-quality (Q)-factor resonances to improve optical devices’ performances. Herein, we demonstrate that high-Q-factor dual-band Fano resonances can be achieved by using a planar nanohole slab (PNS) based on the excitation of dual bound states in the continuum (BICs). By shrinking or expanding the tetramerized holes of the superlattice of the PNS, two symmetry-protected BICs can be induced to dual-band Fano resonances and their locations as well as their Q-factors can be flexibly tuned. Physical mechanisms for the dual-band Fano resonances can be interpreted as the resonant couplings between the electric toroidal dipoles or the magnetic toroidal dipoles based on the far-field multiple decompositions and the near-field distributions of the superlattice. The dual-band Fano resonances of the PNS possess polarization-independent feature, and they can be survived even when the geometric parameters of the PNS are significantly altered, making them more suitable for potential applications.

scholarly journals Tunable Bound States in the Continuum in All-Dielectric Terahertz Metasurfaces

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 623 ◽  
Author(s):  
Xu Chen ◽  
Wenhui Fan
Keyword(s):  
Strontium Titanate ◽  
Fano Resonance ◽  
Bound States ◽  
Cell Structure ◽  
Unit Cell ◽  
Graphene Monolayer ◽  
Quality Factors ◽  
Resonance Amplitude ◽  
Potential Applications ◽  
The Continuum

In this paper, a tunable terahertz dielectric metasurfaces consisting of split gap bars in the unit cell is proposed and theoretically demonstrated, where the sharp high-quality Fano resonance can be achieved through excitation of quasi-bound states in the continuum (quasi-BIC) by breaking in-plane symmetry of the unit cell structure. With the structural asymmetry parameter decreasing and vanishing, the calculated eigenmodes spectra demonstrate the resonance changes from Fano to symmetry-protected BIC mode, and the radiative quality factors obey the inverse square law. Moreover, combining with graphene monolayer and strontium titanate materials, the quasi-BIC Fano resonance can be tuned independently, where the resonance amplitude can be tuned by adjusting the Fermi level of graphene and the resonance frequency can be tuned by controlling the temperature of strontium titanate materials. The proposed structure has numerous potential applications on tunable devices including modulators, switches, and sensors.

scholarly journals Design and simulation of bio fluidic sensor based on photonic crystal

2014 ◽  
Vol 3 (2) ◽  
pp. 106
Author(s):  
Rajini Gaddam Kesava Reddy ◽  
Sharmila Ashok kumar ◽  
Sankardoss Varadhan
Keyword(s):  
Photonic Crystals ◽  
Photonic Band Gap ◽  
Optical Cavity ◽  
Fdtd Method ◽  
High Sensitivity ◽  
Three Dimensions ◽  
Fluidic Channel ◽  
Optical Cavities ◽  
Fluid Sensor ◽  
On Chip

Photonic crystals are materials patterned with a periodicity in dielectric constant in one, two and three dimensions and associated with Bragg scattering which can create range of forbidden frequencies called Photonic Band Gap (PBG). By optimizing various parameters and creating defects, we will review the design and characterization of waveguides, optical cavities and multi-fluidic channel devices. We have used such waveguides and laser nanocavities as Biosensor, in which field intensity is strongly dependent on the type of biofliud and its refractive index. This design and simulation technique leads to development of a nanophotonic sensor for detection of biofluids. In this paper, we have simulated sensing of biofliud in various photonic defect structures with the help of a numerical algorithm called Finite Difference Time Domain (FDTD) method. The simulation result shows the high sensitivity for the change in the bio-molecular structure. For developing the complete sensor system, we have to use the MEMS technologies to integrate on-chip fluidic transport components with sensing systems. The resulting biofluidic system will have the capability to continuously monitor the concentration of a large number of relevant biological molecules continuously from ambulatory patients. Keywords: FDTD, Photonic Crystals, Bio fluid Sensor, Optical Cavity.

scholarly journals Polarization-selective modulation of supercavity resonances originating from bound states in the continuum

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Chan Kyaw ◽  
Riad Yahiaoui ◽  
Joshua A. Burrow ◽  
Viet Tran ◽  
Kyron Keelen ◽  
...  
Keyword(s):  
Strong Coupling ◽  
Bound States ◽  
Photonic Band Gap ◽  
Incidence Angle ◽  
Polarization State ◽  
Normal Incidence ◽  
Polarization Angle ◽  
Sensing Applications ◽  
Symmetry Protected ◽  
The Continuum

AbstractBound states in the continuum (BICs) are widely studied for their ability to confine light, produce sharp resonances for sensing applications and serve as avenues for lasing action with topological characteristics. Primarily, the formation of BICs in periodic photonic band gap structures are driven by symmetry incompatibility; structural manipulation or variation of incidence angle from incoming light. In this work, we report two modalities for driving the formation of BICs in terahertz metasurfaces. At normal incidence, we experimentally confirm polarization driven symmetry-protected BICs by the variation of the linear polarization state of light. In addition, we demonstrate through strong coupling of two radiative modes the formation of capacitively-driven Freidrich-Wintgen BICs, exotic modes which occur in off-Γ points not accessible by symmetry-protected BICs. The capacitance-mediated strong coupling at 0° polarization is verified to have a normalized coupling strength ratio of 4.17% obtained by the Jaynes-Cummings model. Furthermore, when the polarization angle is varied from 0° to 90° (0° ≤ ϕ < 90°), the Freidrich-Wintgen BIC is modulated until it is completely switched off at 90°.

scholarly journals Bound states in the continuum in resonant nanostructures: an overview of engineered materials for tailored applications

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Shereena Joseph ◽  
Saurabh Pandey ◽  
Swagato Sarkar ◽  
Joby Joseph
Keyword(s):  
Bound States ◽  
Beam Steering ◽  
Functional Materials ◽  
Bound State ◽  
Dielectric Medium ◽  
Quality Factors ◽  
Theoretical Frameworks ◽  
Experimental Realization ◽  
Promising Tool ◽  
The Continuum

Abstract From theoretical model to experimental realization, the bound state in the continuum (BIC) is an emerging area of research interest in the last decade. In the initial years, well-established theoretical frameworks explained the underlying physics for optical BIC modes excited in various symmetrical configurations. Eventually, in the last couple of years, optical-BICs were exploited as a promising tool for experimental realization with advanced nanofabrication techniques for numerous breakthrough applications. Here, we present a review of the evolution of BIC modes in various symmetry and functioning mediums along with their application. More specifically, depending upon the nature of the interacting medium, the excitations of BIC modes are classified into the pure dielectric and lossy plasmonic BICs. The dielectric constituents are again classified as photonic crystal functioning in the subwavelength regime, influenced by the diffraction modes and metasurfaces for interactions far from the diffraction regime. More importantly, engineered functional materials evolved with the pure dielectric medium are explored for hybrid-quasi-BIC modes with huge-quality factors, exhibiting a promising approach to trigger the nanoscale phenomena more efficiently. Similarly, hybrid modes instigated by the photonic and plasmonic constituents can replace the high dissipative losses of metallic components, sustaining the high localization of field and high figure of merit. Further, the discussions are based on the applications of the localized BIC modes and high-quality quasi-BIC resonance traits in the nonlinear harmonic generation, refractometric sensing, imaging, lasing, nanocavities, low loss on-chip communication, and as a photodetector. The topology-controlled beam steering and, chiral sensing has also been briefly discussed.

Fine Temperature Measurement and Fabrication of On-Chip Whispering-Gallery Mode Micro-Sensors

2013 ◽  
Author(s):  
Matthew Frenkel ◽  
Marlon Avellan ◽  
Zhixiong Guo
Keyword(s):  
High Sensitivity ◽  
Whispering Gallery Mode ◽  
Heat Transfer Analysis ◽  
Fabrication Technique ◽  
Quality Factors ◽  
High Quality ◽  
Whispering Gallery ◽  
Thermal Measurements ◽  
On Chip

Whispering-Gallery mode based optical micro-devices have been demonstrated to have extremely high sensitivity to changes in local temperature owing to their high quality factors and frequency-based measurements. In this paper, we first examine different fabrication techniques for integrating whispering-gallery mode sensors directly onto heating components to realize on-chip in-situ dynamic temperature measurements and monitoring. The merits and drawbacks of each fabrication technique are discussed. Then, the capability of the fabricated on-chip micro-sensors to perform precise real-time thermal measurements was tested, and the findings are discussed. Finally, the advantages of such on-chip sensors are established through heat transfer analysis.

scholarly journals Bound states in the continuum and strong phase resonances in integrated Gires-Tournois interferometer

Nanophotonics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 83-92 ◽  
Author(s):  
Dmitry A. Bykov ◽  
Evgeni A. Bezus ◽  
Leonid L. Doskolovich
Keyword(s):  
Bound States ◽  
Resonance Effect ◽  
Wave Model ◽  
Slab Waveguide ◽  
Strong Phase ◽  
Practical Applications ◽  
Wide Range ◽  
On Chip ◽  
The Continuum ◽  
Phase Resonance

AbstractPhotonic bound states in the continuum (BICs) are eigenmodes with an infinite lifetime, which coexist with a continuous spectrum of radiating waves. BICs are not only of great theoretical interest but also have a wide range of practical applications, e.g. in the design of optical resonators. Here, we study this phenomenon in a new integrated nanophotonic element consisting of a single dielectric ridge terminating an abruptly ended slab waveguide. This structure can be considered as an on-chip analog of the Gires-Tournois interferometer (GTI). We demonstrate that the proposed integrated structure supports high-Q phase resonances and robust BICs. We develop a simple but extremely accurate coupled-wave model that clarifies the physics of BIC formation and enables predicting BIC locations. The developed model shows that the studied BICs are topologically protected and describes the strong phase resonance effect that occurs when two BICs with opposite topological charges annihilate.

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