Optimal Shape Design of Dielectric Micro Lens Using FDTD and Topology Optimization

Chung, Young-Seek; Lee, Byungje; Kim, Sung‐Chul

doi:10.3807/josk.2009.13.2.286

Cited by 14 publications

(5 citation statements)

References 15 publications

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“…Thus far, most topology optimization methods for nanophotonic structures have been formulated as frequency domain methods, for the design of photonic crystals, dielectric micro lenses, a plasmonic grating coupler, and thin film solar cells . However, frequency domain topology optimization cannot be directly applied for spatiotemporal control of the optical near field because ultrafast optical pulses contain broadband coherent components in the frequency domain.…”

Section: Introductionmentioning

confidence: 99%

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

Yasuda

Yamada

Nishiwaki

2018

Numerical Meth Engineering

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Recently, two emerging areas of photonics research, ultrafast photonics, and nanophotonics have started to come together. One of the main problems in this field is the precise control of spatial and temporal profiles of the optical pulses.In this paper, we propose a design method for user-specified spatiotemporal optical pulses using a level set-based time-domain topology optimization method.In the proposed method, the optimization problem is formulated based on time domain Maxwell equations so that the spatiotemporal optical pulses can be treated directly. The objective function is defined using the envelope information of the pulses, and an efficient way to calculate this information, based on calculations of the complex electromagnetic field, is introduced. A level set-based topology optimization method is applied to obtain optimized configurations.Using the proposed method, the spatiotemporal user-specified pulse profiles can be designed by modifying the structural details of the nanostructures through which the pulses propagate. As a simple example, we demonstrate that the optimized structures focus optical pulses into a single or multiple focal points with a user-specified pulse-width. The results show that the proposed method is able to design highly controlled spatiotemporal optical pulses by engineering the nanophotonic structure. KEYWORDSfinite difference methods, level sets, topology design INTRODUCTIONNanophotonics and ultrafast photonics are main subjects of research in the current photonics research field. Nanophotonics is the study of the behavior of light on the nanometer scale and of the interaction of nanometer-scale objects with light. Nanophotonics is an emerging technology with many applications 1-4 such as surface-enhanced Raman scattering, near field optical microscopy, and metamaterials. On the other hand, ultrafast photonics is the study of light and its interaction with matter on short timescales of less than a picosecond. 5,6 The main interest in this field is to investigate the processes that occur in atoms, molecules, and solids, such as the dynamics of and correlations between electrons.Nanophotonics and ultrafast photonics, which developed independently, have recently started to merge. [7][8][9] In the vicinity of a nanostructure, ultrafast pulses drastically change their spatial and temporal profiles. In other words, the spatiotemporal optical pulse profile can be arbitrarily changed by adjusting the surrounding nanostructure. Spatially and temporally controlled ultrafast pulses potentially offer an efficient way to enhance light-matter interactions at the nanoscale and provide a promising platform for information processing.Int J Numer Methods Eng. 2019;117:605-622.wileyonlinelibrary.com/journal/nme

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Section: Introductionmentioning

confidence: 99%

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

Yasuda

Yamada

Nishiwaki

2018

Numerical Meth Engineering

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“…Besides, the projecting turret increases air resistance and reduces cruising speed. [1][2][3][4] According to the above analysis it is necessary to investigate an improved airborne IR detection system which is inside the plane body to avoid injury, mounts with a tilted porthole conformal to the prow for decreasing air drag and has an appropriate scanning mechanism able to provide a large field of view.…”

Section: Introductionmentioning

confidence: 99%

Airborne Infrared Scanning Imaging System with Rotating Drum for Fire Detection

Song¹,

Chang²,

Cao³

et al. 2011

Journal of the Optical Society of Korea

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Airborne infrared techniques have been used in wild land fire management for decades. This paper describes a kind of infrared scanning system based on a rotating drum with a tilted porthole underside the plane nose. This design increases the stability of the mechanism system, reduces air resistance and protects inner parts. Aberration characteristics of a tilted ellipsoid porthole are analyzed and an effective solution is invented which makes the system achieve 30° field of regard. The system's ultimate value of modulation transfer function is near the diffraction limit, which indicates that the performance of the rotating optical system meets the imaging requirements.

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“…These techniques have been successfully applied for designing microwave components and antennas [18][19][20][21][22][23][24][25], but to the best of our knowledge, never for optimizing the unloaded quality factor of dielectric resonators.…”

Section: Introductionmentioning

confidence: 99%

“…The level-set method [10][11][12][13][14][15][16] relies on the shape derivative where the boundary is moving during the optimization process along the gradient direction. The topology gradient method [17][18][19][20][21] evaluates the gradient with respect to the modification of a topological element, which consists of changing the material characteristics very locally.…”

Section: Introductionmentioning

confidence: 99%

Shape optimization of a dielectric resonator for improving its unloaded quality factor

Khalil¹,

Bila²,

Aubourg³

et al. 2010

Int J RF and Microwave Comp Aid Eng

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International audienceA novel approach for shape optimization of dielectric resonators is presented with an objective of improving their unloaded quality factor. Shape (level-set) and topology (topology gradient) optimization methods coupled with finite element method are utilized together, which as a result, relaxes the traditional trade-off made between the spurious-free band (isolation) and the high unloaded quality factor of the resonators. The defined cost function is minimized by the proposed iterative coupling between the level-set method and the topology gradient method. The optimized resonator, which improves the unloaded quality factor of about 65% compared with the reference, is then approximated for fabrication. The reference, optimized, and approximated resonators are fabricated and measured. Results from the simulated and the fabricated resonators validate the optimization approach presented in this work

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Optimal Shape Design of Dielectric Micro Lens Using FDTD and Topology Optimization

Cited by 14 publications

References 15 publications

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

A design method of spatiotemporal optical pulse using level‐set based time domain topology optimization

Airborne Infrared Scanning Imaging System with Rotating Drum for Fire Detection

Shape optimization of a dielectric resonator for improving its unloaded quality factor

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