Article
Physics, Multidisciplinary
Stephen Sanders, Lauren Zundel, Wilton J. M. Kort-Kamp, Diego A. R. Dalvit, Alejandro Manjavacas
Summary: The study presents a theoretical framework for describing the temporal dynamics of radiative heat transfer in ensembles of nanostructures using an eigenmode expansion. The results reveal fundamental principles governing the thermalization of collections of nanostructures.
PHYSICAL REVIEW LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Rohith Mittapally, Ju Won Lim, Lang Zhang, Owen D. Miller, Pramod Reddy, Edgar Meyhofer
Summary: Recent experiments have revealed that near-field radiative heat transfer (NFRHT) between objects separated by nanoscale gaps can significantly enhance heat transfer rates. Silicon dioxide (SiO2) surfaces, which support surface phonon polaritons (SPhP), demonstrate the most prominent enhancements. However, theoretical analysis suggests that SPhPs in SiO2 occur at frequencies much higher than optimal. In this study, we demonstrate theoretically that NFRHT mediated by SPhPs can be 5-fold larger for materials supporting SPhPs closer to the optimal frequency of 67 meV at room temperature. Furthermore, we experimentally show that MgF2 and Al2O3 closely approach this limit, with near-field thermal conductance between MgF2 plates separated by 50 nm reaching nearly 50% of the global SPhP bound. These findings lay the foundation for exploring the limits of radiative heat transfer rates at the nanoscale.
Article
Thermodynamics
Jihong Zhang, Haotuo Liu, Kaihua Zhang, Jiangcheng Cao, Xiaohu Wu
Summary: This paper investigates the radiative heat transfer between stacked structures consisting of two different hyperbolic materials in both near-field and far-field. The results show that the far-field heat transfer is mainly affected by the substrate material, while the near-field heat transfer is dominated by the hyperbolic film. Additionally, the performance of heat transfer is influenced by the combination of different materials.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Materials Science, Multidisciplinary
Jonathan L. Wise, Denis M. Basko
Summary: In this study, the radiative heat current between two thin metallic layers separated by a vacuum gap was analytically calculated using the standard fluctuational electrodynamics framework. The role of dc conductivity of the metals compared to the speed of light in determining the heat current was identified, with different behaviors observed for poorly conducting metals versus well-conducting metals. Evanescent waves and their dominant role in heat current contributions were discussed in relation to the separation distance between the layers and the thermal wavelength.
Article
Thermodynamics
S. G. Castillo-Lopez, C. Villarreal, R. Esquivel-Sirvent, G. Pirruccio
Summary: This theoretical study focuses on the near-field radiative heat transfer between high-T-c superconducting thin films, showing that thin films enhance heat transfer significantly compared to bulk plates. The optical response above and below T-c plays a crucial role, with the superconducting phase transition leading to a suppression of total heat flux.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Multidisciplinary Sciences
Ivan Latella, Philippe Ben-Abdallah
Summary: A many-body conversion principle is introduced to harvest strong electromagnetic energy density near a hot solid using graphene-based pyroelectric conversion devices. Controlling the thermal state and spontaneous polarization of the active layer allows for high power density generation.
SCIENTIFIC REPORTS
(2021)
Article
Physics, Multidisciplinary
David Gelbwaser-Klimovsky, Noah Graham, Mehran Kardar, Matthias Krueger
Summary: Research suggests that a ratchetlike lateral Casimir force between two plates at different temperatures and with broken inversion symmetry cannot solely be explained by arguments based on symmetry and thermodynamics. At least one plate must be made of nonreciprocal material to transform heat radiation into mechanical force for the heat engine to operate. The ratio of the lateral force to heat transfer in the near field regime diverges inversely with the plates separation, d, but the engine efficiency is limited to the Carnot value by an extended Onsager symmetry.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
M. Reina, R. Messina, P. Ben-Abdallah
Summary: When two solids at different temperatures are separated by a vacuum gap, they exchange heat through radiation, phonon, or electron tunneling to reach equilibrium. A significant slowing-down of energy exchange is observed in the extreme near-field regime, impacting the temporal evolution of the thermal state of interacting solid systems at nanometric and subnanometric scales.
Article
Chemistry, Multidisciplinary
Kezhang Shi, Zhaoyang Chen, Yuxin Xing, Jianxin Yang, Xinan Xu, Julian S. Evans, Sailing He
Summary: This study demonstrates the challenges of modulating near-field radiative heat transfer (NFRHT) with a high dynamic range in nanoscale thermal science and engineering. The researchers achieved a modulation depth of approximately 32.2% using a pair of graphene-covered SU8 heterostructures. The results show the importance of symmetry in polariton-mediated NFRHT and represent the largest modulation depth to date in a two-body system with fixed gap distance and temperature.
Article
Physics, Fluids & Plasmas
Leila Ghaderipoor, Mohammad Mardaani, Ehsan Amooghorban, Hassan Rabani
Summary: By using the extended mass-spring chain model, this study investigates the contribution of phonons to heat transport across a narrow vacuum gap through the harmonic approximation and Green's function technique. It shows that the phonon transmission across the vacuum gap can be improved under specific values of interaction strengths, incoming phonon frequency, and gap distance. The thermal conductance of the system is calculated as a function of interaction strength, gap distance, and temperature, revealing a suitable fitting function for determining or controlling the internal interaction strengths.
Article
Optics
Lu Lu, Bo Zhang, Bowen Li, Jinlin Song, Zixue Luo, Qiang Cheng
Summary: Magneto-optical materials have the potential to actively control near-field radiative heat transfer under weak magnetic fields. This study investigates the NFRHT between dual MO graphene/InSb core-shell nanoparticles-based metamaterials and provides insights into the physical mechanisms and applications of magnetic field-controlled devices.
Article
Physics, Applied
S. G. Castillo-Lopez, P. Esquivel-Sirvent, C. Villarreal, G. Pirruccio
Summary: Engineering the heat flux between two surfaces at different temperatures can be effectively achieved by tailoring the dispersion of modes using metasurfaces. This can be done by manipulating the geometrical parameters and controlling the excitation or suppression of surface and hyperbolic modes.
APPLIED PHYSICS LETTERS
(2022)
Article
Thermodynamics
Ming-Qian Yuan, Yong Zhang, Shui-Hua Yang, Hong-Liang Yi
Summary: The study focuses on the near-field radiative heat transfer (NFRHT) between charged metallic plates under an external electric field, showing that copper plates have the largest NFRHT. The p-wave heat flux is greatly amplified by the perpendicular electric field, leading to rapid increase in heat flux between copper plates. The external electric field can be used to control NFRHT, which has various applications in thermal nano-devices.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Physics, Multidisciplinary
Peng Tian, Wenxuan Ge, Songsong Li, Lei Gao, Jianhua Jiang, Yadong Xu
Summary: Research on near-field radiative heat transfer (NFRHT) is an important project in nanotechnology following a major breakthrough. By studying the effects of multilayer structures, we discovered that changing the filling ratio can lead to the decoupling of hyperbolic modes (HMs) and the suppression of heat flow. We also found that introducing disorder in the layer thickness can affect heat transfer, although the reduction in heat transfer is not significant even with large disorder. This work provides valuable insights for understanding the impact of disorder on NFRHT and guiding the fabrication of NFRHT devices.
CHINESE PHYSICS LETTERS
(2023)
Article
Thermodynamics
Song Li, Deyu Xu, Junming Zhao, Linhua Liu
Summary: This study theoretically investigates the effect of surface roughness on the performance of near-field thermophotovoltaic (NF-TPV) systems. The results show that surface roughness changes the mode of near-field radiative heat transfer and affects the system's performance, depending on the cooperation between the resonance frequency of the emitter and the bandgap of the TPV cell.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Physics, Applied
Ying Pan, Rasmus E. Christiansen, Jerome Michon, Juejun Hu, Steven G. Johnson
Summary: Surface-enhanced Raman spectroscopy (SERS) is a powerful sensing method with the potential to detect single molecules, and topology optimization (TopOpt) can be used to design SERS substrates adhering to realistic fabrication constraints. By relaxing the fabrication minimum-feature-size constraint, TopOpt can be used to design SERS substrates with orders of magnitude larger enhancement factors. The results validate topology optimization as an effective method for engineering optimized SERS nanostructures adhering to fabrication limitations.
APPLIED PHYSICS LETTERS
(2021)
Article
Optics
Alec M. Hammond, Ardavan Oskooi, Steven G. Johnson, Stephen E. Ralph
Summary: This study presents a unified density-based topology optimization framework for optimizing integrated photonic designs for manufacturing constraints such as minimum area, minimum enclosed area, linewidth, linespacing, and curvature. Differentiable morphological transforms are utilized to create devices that are robust to etching issues and meet manufacturing constraints.
Article
Physics, Applied
Fan Wang, Steven G. Johnson, Henry O. Everitt
Summary: The performance of powerful tunable narrow-band continuous-wave terahertz radiation lasers heavily relies on molecular collision physics, pump saturation, and laser cavity design. An optimized laser cavity can produce tens of milliwatts of power tunable over frequencies above 1 THz when pumped by a multiwatt QCL.
PHYSICAL REVIEW APPLIED
(2021)
Article
Optics
Alec M. Hammond, Ardavan Oskooi, Mo Chen, Zin Lin, Steven G. Johnson, Stephen E. Ralph
Summary: We present a photonics topology optimization (TO) package that can address a wide range of practical photonics design problems. The package incorporates robustness and manufacturing constraints and can scale to large devices and massive parallelism. It employs a hybrid algorithm that solves multiple frequency-domain TO problems using a mature time-domain (FDTD) package and is enhanced by new filter-design sources and material-interpolation methods.
Article
Optics
Zin Lin, Raphael Pestourie, Charles Roques-Carmes, Zhaoyi Li, Federico Capasso, Marin Soljacic, Steven G. Johnson
Summary: We introduce end-to-end inverse design for multi-channel imaging, which involves optimizing a nanophotonic frontend and an image-processing backend to extract depth, spectral, and polarization channels from a single monochrome image. We demonstrate that subwavelength-scale metasurface designs can easily distinguish similar wavelength and polarization inputs, unlike diffractive optics. Our proposed technique combines a single-layer metasurface frontend with an efficient Tikhonov reconstruction backend, requiring only a grayscale sensor. Through spontaneous demultiplexing, our method achieves multi-channel imaging by separating different channels into distinct spatial domains on the sensor. We present large-area metasurface designs for multi-spectral imaging, depth-spectral imaging, and all-in-one spectro-polarimetric-depth imaging, demonstrating robust reconstruction performance.
Article
Physics, Applied
Mohammed Benzaouia, John D. Joannopoulos, Steven G. Johnson, Aristeidis Karalis
Summary: This study presents general analytical criteria for designing standard filters and demonstrates the method of designing filter devices through specific unitary coupling ratios. By solving a nonlinear optimization problem, filter design can be achieved, with a focus on elliptic filters for optimal performance.
PHYSICAL REVIEW APPLIED
(2022)
Article
Optics
Wenjie Yao, Francesc Verdugo, Henry O. Everit, Rasmus E. Christiansen, Steven G. Johnson
Summary: We propose a general framework for inverse design of nanopatterned surfaces that maximize surface-enhanced Raman spectra from randomly distributed molecules. Our optimized structures outperform coating with optimized spheres or bowtie structures by about 4 and 20 times, respectively, when considering nonlinear damage effects.
Article
Computer Science, Interdisciplinary Applications
Giuseppe Romano, Steven G. Johnson
Summary: In this study, a methodology for density-based topology optimization of non-Fourier thermal transport in nanostructures is introduced. It utilizes adjoint-based sensitivity analysis of the phonon Boltzmann transport equation (BTE) and a novel material interpolation technique called the transmission interpolation model (TIM). The approach is able to handle the interplay between real- and momentum-resolved material properties by parameterizing the material density with an interfacial transmission coefficient. This methodology allows for the systematic optimization of materials for heat management and conversion, as well as the design of devices where diffusive transport is not valid.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Nanoscience & Nanotechnology
Pengning Chao, Rodrick Kuate Defo, Sean Molesky, Alejandro Rodriguez
Summary: The local density of states (LDOS) plays a crucial role in photonics engineering. We propose a framework for evaluating upper bounds on LDOS in structured media, which can handle arbitrary bandwidths and considers wave scattering effects. We derive an analytical expression for the maximum LDOS and discover scaling laws for maximum LDOS enhancement, with implications on material selection and design applications.
Article
Optics
Mohammed Benzaouia, A. D. Stone, Steven G. Johnson
Summary: In this study, a general analysis is presented for finding and characterizing nonlinear exceptional point (EP) lasers above threshold. The stability of the EP laser is confirmed through numerical analysis, and a new method for characterizing the EP laser is proposed.
Article
Optics
Sophie Fisher, Raphael Pestourie, Steven G. Johnson
Summary: This study presents a semianalytical framework for computing the coupling of radiative and guided waves in slowly varying surfaces. It fills the gap in current approximate methods by allowing the modeling of their coupling using a combination of two methods.
Article
Physics, Multidisciplinary
Lu Lu, Raphael Pestourie, Steven G. Johnson, Giuseppe Romano
Summary: This paper proposes a multifidelity neural operator based on deep neural networks, which can reduce the demand for high-fidelity data and achieve smaller errors in solving heat transport problems. By combining with genetic algorithms and topology optimization, it enables fast solvers and inverse design for the phonon Boltzmann transport equation (BTE).
PHYSICAL REVIEW RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Chinmay Khandekar, Siddharth Buddhiraju, Paul R. Wilkinson, James K. Gimzewski, Alejandro W. Rodriguez, Charles Chase, Shanhui Fan
Summary: This study demonstrates that an isotropic dipolar particle near an asymmetric medium surface may experience lateral force and torque when the particle's temperature differs from the surrounding environment. The presence of the lateral force is associated with the asymmetric dispersion of nonreciprocal surface polaritons, while the presence of lateral torque is linked to the spin-momentum locking of surface waves. Additionally, it is found that the directions of the lateral force and torque are dependent on the constituent materials of the particles.
Article
Materials Science, Multidisciplinary
Yi-Xin Sha, Bo-Yuan Liu, Hao-Zhe Gao, Heng-Bin Cheng, Hai-Li Zhang, Ming-Yao Xia, Steven G. Johnson, Ling Lu
Summary: The iterative Green's function based on cyclic reduction of block-tridiagonal matrices is an ideal algorithm to compute the surface density of states of semi-infinite topological electronic materials. This method is applied to photonic and acoustic crystals using finite-element discretization and a generalized eigenvalue formulation to calculate the local density of states on a single surface of semi-infinite lattices. Three-dimensional examples of gapless helicoidal surface states in Weyl and Dirac crystals are shown, and the computational cost, convergence, and accuracy are analyzed.
Article
Physics, Multidisciplinary
Mohammed Benzaouia, John D. Joannopoulos, Steven G. Johnson, Aristeidis Karalis
Summary: Researchers have developed a quasi-normal mode theory for calculating a system's scattering S matrix, which simultaneously satisfies energy conservation and reciprocity. This practical reduced-order model is based on resonant frequencies and constant mode-to-port coupling coefficients, and can easily compute and describe various electromagnetic metasurfaces' Fano resonant phenomena.
PHYSICAL REVIEW RESEARCH
(2021)