K. Munechika, Jiye Lee, D. Simatos, M. Melli, S. Whitelam, A. Weber-Bargioni
Semiconductor quantum dots are considered a promising material class with the potential of highly tunable and novel optoelectronic properties. Recent research efforts have shown that quantum dots, assembled in well-ordered 1D, 2D and 3D geometries have the potential to funnel excitons via Forster Resonance Energy Transfer (FRET) through the nanocrystal composite. Understanding the inter quantum dot coupling and the spatial extend of exciton diffusion is key to design material for the deliberate control of energy transport through them. In this regard, we study Förster Resonance Energy Transfer (FRET) between CdSe quantum dots in a well-defined 2D assembly with different interparticle distances. We then examine the spatial extent of FRET coupling between quantum dots using confocal fluorescence hyperspectral imaging. We spatially map out the degree of the coupling between the neighboring quantum dots by exciting the quantum dots at a known location and collect fluorescence signals at various distances relative to the excitation. We show that by varying the dimensionality, energy landscape, and exciton density, we are able to manipulate the spatial extent of exciton diffusion through the QDs assembly. Modeling was done in conjunction the experiments and well described our observations in each case. The results provide in-depth understanding into the spatial extent of exciton diffusion via FRET through ordered quantum dot assemblies and provide useful insights in engineering nano-building structures to direct and enhance the direction of the exciton transport to a preferred sites.
{"title":"Manipulating the spatial extent of the exciton diffusion through QDs assembly by controlling dimensionality, energy landscape, and exciton density (Presentation Recording)","authors":"K. Munechika, Jiye Lee, D. Simatos, M. Melli, S. Whitelam, A. Weber-Bargioni","doi":"10.1117/12.2194334","DOIUrl":"https://doi.org/10.1117/12.2194334","url":null,"abstract":"Semiconductor quantum dots are considered a promising material class with the potential of highly tunable and novel optoelectronic properties. Recent research efforts have shown that quantum dots, assembled in well-ordered 1D, 2D and 3D geometries have the potential to funnel excitons via Forster Resonance Energy Transfer (FRET) through the nanocrystal composite. Understanding the inter quantum dot coupling and the spatial extend of exciton diffusion is key to design material for the deliberate control of energy transport through them. In this regard, we study Förster Resonance Energy Transfer (FRET) between CdSe quantum dots in a well-defined 2D assembly with different interparticle distances. We then examine the spatial extent of FRET coupling between quantum dots using confocal fluorescence hyperspectral imaging. We spatially map out the degree of the coupling between the neighboring quantum dots by exciting the quantum dots at a known location and collect fluorescence signals at various distances relative to the excitation. We show that by varying the dimensionality, energy landscape, and exciton density, we are able to manipulate the spatial extent of exciton diffusion through the QDs assembly. Modeling was done in conjunction the experiments and well described our observations in each case. The results provide in-depth understanding into the spatial extent of exciton diffusion via FRET through ordered quantum dot assemblies and provide useful insights in engineering nano-building structures to direct and enhance the direction of the exciton transport to a preferred sites.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130682961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yue Sun, S. Suchkov, A. Miroshnichenko, A. Sukhorukov
We demonstrate that a gold split-ball resonator (SBR) in the form of a spherical nanoparticle with a cut supports both optical magnetic and acoustic modes, which have strong field confinement around the cut. Such localization away from the bottom is expected to lead to an immunity to anchor loss and thus potentially high quality factors of acoustic oscillations when positioned on a substrate. As a result, when a planewave pulse excites the optical resonance, it can then efficiently drive the acoustic vibration through laser heating and/or optical forces. We estimate the overall heat variation by modelling the optical energy dissipation inside the SBR due to the dispersive and absorbing nature of gold at optical wavelengths. The optically induced force is given by the time averaged Lorentz force density. We simulate the mechanical vibrations under the optical excitation through time-dependent simulations using solid mechanics module of COMSOL software. Assuming a moderate quality factor of 10, under a plane wave pulsed laser pump which gives 100K temperature change to the SBR, both the laser heating and optical forces lead to the excitation of the acoustic mode at the same frequency with different magnitudes of 200pm and 10pm, resulting 10% and 0.5% modification of the total optical scattering, respectively. These results show that the SBRs support strong opto-mechanical coupling and are promising in applications such as surface-enhanced Raman spectroscopy and detection of localised strain.
{"title":"Opto-mechanical interactions in split ball resonators (Presentation Recording)","authors":"Yue Sun, S. Suchkov, A. Miroshnichenko, A. Sukhorukov","doi":"10.1117/12.2190289","DOIUrl":"https://doi.org/10.1117/12.2190289","url":null,"abstract":"We demonstrate that a gold split-ball resonator (SBR) in the form of a spherical nanoparticle with a cut supports both optical magnetic and acoustic modes, which have strong field confinement around the cut. Such localization away from the bottom is expected to lead to an immunity to anchor loss and thus potentially high quality factors of acoustic oscillations when positioned on a substrate. As a result, when a planewave pulse excites the optical resonance, it can then efficiently drive the acoustic vibration through laser heating and/or optical forces. We estimate the overall heat variation by modelling the optical energy dissipation inside the SBR due to the dispersive and absorbing nature of gold at optical wavelengths. The optically induced force is given by the time averaged Lorentz force density. We simulate the mechanical vibrations under the optical excitation through time-dependent simulations using solid mechanics module of COMSOL software. Assuming a moderate quality factor of 10, under a plane wave pulsed laser pump which gives 100K temperature change to the SBR, both the laser heating and optical forces lead to the excitation of the acoustic mode at the same frequency with different magnitudes of 200pm and 10pm, resulting 10% and 0.5% modification of the total optical scattering, respectively. These results show that the SBRs support strong opto-mechanical coupling and are promising in applications such as surface-enhanced Raman spectroscopy and detection of localised strain.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121610352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Solid-state junctions based on a metal-insulator-semiconductor (MIS) architecture are of great interest for a number of optoelectronic applications such as photovoltaics, photoelectrochemical cells, and photodetection. One major advantage of the MIS junction compared to the closely related metal-semiconductor junction, or Schottky junction, is that the thin insulating layer (1-3 nm thick) that separates the metal and semiconductor can significantly reduce the density of undesirable interfacial mid-gap states. The reduction in mid-gap states helps “un-pin” the junction, allowing for significantly higher built-in-voltages to be achieved. A second major advantage of the MIS junction is that the thin insulating layer can also protect the underlying semiconductor from corrosion in an electrochemical environment, making the MIS architecture well-suited for application in (photo)electrochemical applications. In this presentation, discontinuous Si-based MIS junctions immersed in electrolyte are explored for use as i.) photoelectrodes for solar-water splitting in photoelectrochemical cells (PECs) and ii.) position-sensitive photodetectors. The development and optimization of MIS photoelectrodes for both of these applications relies heavily on understanding how processing of the thin SiO2 layer impacts the properties of nano- and micro-scale MIS junctions, as well as the interactions of the insulating layer with the electrolyte. In this work, we systematically explore the effects of insulator thickness, synthesis method, and chemical treatment on the photoelectrochemical and electrochemical properties of these MIS devices. It is shown that electrolyte-induced inversion plays a critical role in determining the charge carrier dynamics within the MIS photoelectrodes for both applications.
{"title":"The role of ultra-thin SiO2 layers in metal-insulator-semiconductor (MIS) photoelectrochemical devices (Presentation Recording)","authors":"D. Esposito","doi":"10.1117/12.2190513","DOIUrl":"https://doi.org/10.1117/12.2190513","url":null,"abstract":"Solid-state junctions based on a metal-insulator-semiconductor (MIS) architecture are of great interest for a number of optoelectronic applications such as photovoltaics, photoelectrochemical cells, and photodetection. One major advantage of the MIS junction compared to the closely related metal-semiconductor junction, or Schottky junction, is that the thin insulating layer (1-3 nm thick) that separates the metal and semiconductor can significantly reduce the density of undesirable interfacial mid-gap states. The reduction in mid-gap states helps “un-pin” the junction, allowing for significantly higher built-in-voltages to be achieved. A second major advantage of the MIS junction is that the thin insulating layer can also protect the underlying semiconductor from corrosion in an electrochemical environment, making the MIS architecture well-suited for application in (photo)electrochemical applications. In this presentation, discontinuous Si-based MIS junctions immersed in electrolyte are explored for use as i.) photoelectrodes for solar-water splitting in photoelectrochemical cells (PECs) and ii.) position-sensitive photodetectors. The development and optimization of MIS photoelectrodes for both of these applications relies heavily on understanding how processing of the thin SiO2 layer impacts the properties of nano- and micro-scale MIS junctions, as well as the interactions of the insulating layer with the electrolyte. In this work, we systematically explore the effects of insulator thickness, synthesis method, and chemical treatment on the photoelectrochemical and electrochemical properties of these MIS devices. It is shown that electrolyte-induced inversion plays a critical role in determining the charge carrier dynamics within the MIS photoelectrodes for both applications.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125219950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Josslyn Beltran Madrigal, M. Berthel, F. Gardillou, Ricardo Tellez Limon, C. Couteau, D. Barbier, A. Drezet, R. Salas-Montiel, S. Huant, S. Blaize, W. Geng
Several works have already shown that the excitation of plasmonic structures through waveguides enables a strong light confinement and low propagation losses [1]. This kind of excitation is currently exploited in areas such as biosensing [2], nanocircuits[3] and spectroscopy[4]. The efficient excitation of surface plasmon modes (SPP) with guided modes supported by high-index-contrast waveguides, such as silicon-on-insulator waveguides, had already been shown [1,5]. However, the use of weakconfined guided modes of a glass ion exchanged waveguide as a SPP excitation source represents a technological challenge, because the mismatch between the size of their respective electromagnetic modes is so high that the resultant coupling loss is unacceptable for practical applications. In this work, we describe how an adiabatic taper structure formed by an intermediate high-index-contrast layer placed between a plasmonic structure and an ion-exchanged waveguide decreases the mismatch between effective indices, size, and shape of the guided modes. This hybrid structure concentrates the electromagnetic energy from the micrometer to the nanometer scale with low coupling losses to radiative modes. The electromagnetic mode confined to the high-index-contrast waveguide then works as an efficient source of SPP supported by metallic nanostructures placed on its surface. We theoretically studied the modal properties and field distribution along the adiabatic coupler structure. In addition, we fabricated a high-index-contrast waveguide by electron beam lithography and thermal evaporation on top of an ion-exchanged waveguide on glass. This structure was characterized with the use of near field scanning optical microscopy (NSOM). Numerical simulations were compared with the experimental results. [1] N. Djaker, R. Hostein, E. Devaux, T. W. Ebbesen, and H. Rigneault, and J. Wenger, J. Phys. Chem. C 114, 16250 (2010). [2] P. Debackere, S. Scheerlinck, P. Bienstman, R. Baets, Opt. Express 14, 7063 (2006).] [3] A. A. Reiserer, J.-S. Huang, B. Hecht, and T. Brixner. Opt. Express 18(11), 11810–11820 (2010). [4] R. Salas-Montiel, A. Apuzzo, C. Delacour, Z. Sedaghat, A. Bruyant et al. Appl. Phys Lett 100, 231109 (2012) [5] A. Apuzzo M. Fevier, M. Salas-Montiel et al. Nano letters, 13, 1000-1006
{"title":"Adiabatic mode coupler on ion-exchanged waveguides for the efficient excitation of surface plasmon modes (Presentation Recording)","authors":"Josslyn Beltran Madrigal, M. Berthel, F. Gardillou, Ricardo Tellez Limon, C. Couteau, D. Barbier, A. Drezet, R. Salas-Montiel, S. Huant, S. Blaize, W. Geng","doi":"10.1117/12.2188304","DOIUrl":"https://doi.org/10.1117/12.2188304","url":null,"abstract":"Several works have already shown that the excitation of plasmonic structures through waveguides enables a strong light confinement and low propagation losses [1]. This kind of excitation is currently exploited in areas such as biosensing [2], nanocircuits[3] and spectroscopy[4]. The efficient excitation of surface plasmon modes (SPP) with guided modes supported by high-index-contrast waveguides, such as silicon-on-insulator waveguides, had already been shown [1,5]. However, the use of weakconfined guided modes of a glass ion exchanged waveguide as a SPP excitation source represents a technological challenge, because the mismatch between the size of their respective electromagnetic modes is so high that the resultant coupling loss is unacceptable for practical applications. In this work, we describe how an adiabatic taper structure formed by an intermediate high-index-contrast layer placed between a plasmonic structure and an ion-exchanged waveguide decreases the mismatch between effective indices, size, and shape of the guided modes. This hybrid structure concentrates the electromagnetic energy from the micrometer to the nanometer scale with low coupling losses to radiative modes. The electromagnetic mode confined to the high-index-contrast waveguide then works as an efficient source of SPP supported by metallic nanostructures placed on its surface. We theoretically studied the modal properties and field distribution along the adiabatic coupler structure. In addition, we fabricated a high-index-contrast waveguide by electron beam lithography and thermal evaporation on top of an ion-exchanged waveguide on glass. This structure was characterized with the use of near field scanning optical microscopy (NSOM). Numerical simulations were compared with the experimental results. [1] N. Djaker, R. Hostein, E. Devaux, T. W. Ebbesen, and H. Rigneault, and J. Wenger, J. Phys. Chem. C 114, 16250 (2010). [2] P. Debackere, S. Scheerlinck, P. Bienstman, R. Baets, Opt. Express 14, 7063 (2006).] [3] A. A. Reiserer, J.-S. Huang, B. Hecht, and T. Brixner. Opt. Express 18(11), 11810–11820 (2010). [4] R. Salas-Montiel, A. Apuzzo, C. Delacour, Z. Sedaghat, A. Bruyant et al. Appl. Phys Lett 100, 231109 (2012) [5] A. Apuzzo M. Fevier, M. Salas-Montiel et al. Nano letters, 13, 1000-1006","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127832707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Spin orbit coupling at interfaces can give rise to chiral magnetic textures such as homochiral domain walls and skyrmions, as well as current-induced torques that can effectively manipulate them [1-3]. This talk will describe interface-driven spin-orbit torques and Dzyaloshinskii-Moriya interactions (DMIs) in ultrathin metallic ferromagnets adjacent to nonmagnetic heavy metals. We show that the DMI depends strongly on the heavy metal, differing by a factor of ~20 between Pt and Ta [4], and describe the influence of strong DMI on domain wall dynamics and spin Hall effect switching [5]. We present high-resolution magnetic force microscopy imaging of static magnetic textures that directly reveal the role of DMI and allow its strength to be quantified. Finally, we will describe how SOTs can be enhanced through interface engineering [6] and tuned by a gate voltage [7] by directly controlling the interfacial oxygen coordination at a ferromagnet/oxide interface [8]. [1] A. Thiaville, et al., Europhys. Lett. 100, 57002 (2012). [2] S. Emori, et al., Nature Mater. 12, 611 (2013). [3] J. Sampaio, V. Cros, S. Rohart, A. Thiaville, and A. Fert, Nature Nano. 8, 839 (2013). [4] S. Emori, et al., Phys. Rev. B 90, 184427 (2014). [5] N. Perez, et al., Appl. Phys. Lett. 104, 092403 (2014). [6] S. Woo, et al., Appl. Phys. Lett. 105, 212404 (2014). [7] S. Emori, et al., Appl. Phys. Lett. 105, 222401 (2014). [8] U. Bauer, et al., Nature Mater. 14, 174 (2015).
界面处的自旋轨道耦合可以产生手性磁织构，如同手性畴壁和skyrmions，以及可以有效操纵它们的电流诱导转矩[1-3]。本次演讲将描述界面驱动的自旋轨道扭矩和Dzyaloshinskii-Moriya相互作用(dmii)在与非磁性重金属相邻的超薄金属铁磁体中。我们发现DMI强烈依赖于重金属，在Pt和Ta之间相差约20倍[4]，并描述了强DMI对畴壁动力学和自旋霍尔效应开关的影响[5]。我们展示了静态磁性结构的高分辨率磁力显微镜成像，直接揭示了DMI的作用，并允许其强度被量化。最后，我们将描述如何通过界面工程[6]增强sot，并通过直接控制铁磁体/氧化物界面上的界面氧配位[8]通过栅极电压[7]进行调谐。[1]李晓明，李晓明，等。植物学报，2000,57002(2012)。[2]王晓明，王晓明，王晓明，等。气候变化与气候变化的关系。[3]张晓明，张晓明，张晓明，等。中国科学:自然科学进展，2013,33(4):387 - 387。[4]李春华，李春华，等。Rev. B 90, 184427(2014)。[5]李志强，李志强，等。理论物理。生物工程学报，2014,29(2)。[6]吴志强，李志强，等。理论物理。快报，105,212404(2014)。[7]李春华，李春华。理论物理。科学通报，2014,22(2)。[8]王晓明，王晓明，等。生物多样性与生物多样性研究进展。
{"title":"Spin orbit torques and chiral spin textures in ultrathin magnetic films (Presentation Recording)","authors":"G. Beach","doi":"10.1117/12.2191374","DOIUrl":"https://doi.org/10.1117/12.2191374","url":null,"abstract":"Spin orbit coupling at interfaces can give rise to chiral magnetic textures such as homochiral domain walls and skyrmions, as well as current-induced torques that can effectively manipulate them [1-3]. This talk will describe interface-driven spin-orbit torques and Dzyaloshinskii-Moriya interactions (DMIs) in ultrathin metallic ferromagnets adjacent to nonmagnetic heavy metals. We show that the DMI depends strongly on the heavy metal, differing by a factor of ~20 between Pt and Ta [4], and describe the influence of strong DMI on domain wall dynamics and spin Hall effect switching [5]. We present high-resolution magnetic force microscopy imaging of static magnetic textures that directly reveal the role of DMI and allow its strength to be quantified. Finally, we will describe how SOTs can be enhanced through interface engineering [6] and tuned by a gate voltage [7] by directly controlling the interfacial oxygen coordination at a ferromagnet/oxide interface [8]. [1] A. Thiaville, et al., Europhys. Lett. 100, 57002 (2012). [2] S. Emori, et al., Nature Mater. 12, 611 (2013). [3] J. Sampaio, V. Cros, S. Rohart, A. Thiaville, and A. Fert, Nature Nano. 8, 839 (2013). [4] S. Emori, et al., Phys. Rev. B 90, 184427 (2014). [5] N. Perez, et al., Appl. Phys. Lett. 104, 092403 (2014). [6] S. Woo, et al., Appl. Phys. Lett. 105, 212404 (2014). [7] S. Emori, et al., Appl. Phys. Lett. 105, 222401 (2014). [8] U. Bauer, et al., Nature Mater. 14, 174 (2015).","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132517587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Alloatti, C. Kieninger, A. Frölich, M. Lauermann, T. Frenzel, K. Köhnle, W. Freude, J. Leuthold, C. Koos, M. Wegener
[invited] We introduce ABC laminate metamaterials composed of layers of three different dielectrics. Each layer has zero bulk second-order optical nonlinearity, yet centro-symmetry is broken locally at each inner interface. To achieve appreciable effective bulk metamaterial second-order nonlinear optical susceptibilities, we densely pack many inner surfaces to a stack of atomically thin layers grown by conformal atomic-layer deposition. For the ABC stack, centro-symmetry is also broken macroscopically. Our experimental results for excitation at around 800 nm wavelength indicate interesting application perspectives for frequency conversion or electro-optic modulation in silicon photonics.
{"title":"Second-harmonic generation from atomic-scale ABC-type laminate optical metamaterials (Presentation Recording)","authors":"L. Alloatti, C. Kieninger, A. Frölich, M. Lauermann, T. Frenzel, K. Köhnle, W. Freude, J. Leuthold, C. Koos, M. Wegener","doi":"10.1117/12.2187154","DOIUrl":"https://doi.org/10.1117/12.2187154","url":null,"abstract":"[invited] We introduce ABC laminate metamaterials composed of layers of three different dielectrics. Each layer has zero bulk second-order optical nonlinearity, yet centro-symmetry is broken locally at each inner interface. To achieve appreciable effective bulk metamaterial second-order nonlinear optical susceptibilities, we densely pack many inner surfaces to a stack of atomically thin layers grown by conformal atomic-layer deposition. For the ABC stack, centro-symmetry is also broken macroscopically. Our experimental results for excitation at around 800 nm wavelength indicate interesting application perspectives for frequency conversion or electro-optic modulation in silicon photonics.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128335362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metasurfaces composed of sub-wavelength artificial structures show promise for extraordinary light-manipulation and development of ultrathin optical components such as lenses, wave plates, orbital angular detection, and holograms over a broad range of the electromagnetic spectrum. However structures developed to date do not allow for post-fabrication control of antenna properties. We have investigated the integration of the transparent conductor indium tin oxide (ITO) active elements to realize gate-tunable phased arrays of subwavelength patch antenna in a metasurface configuration to enable gate tunable permittivity. The magnetic dipole resonance of each patch antenna interacts with the carrier density-dependent permittivity resonance of the ITO to enable phase and amplitude tunability. Operation of patch antennas and beam steering phased arrays will be discussed.
{"title":"Tunable metasurfaces (Presentation Recording)","authors":"H. Atwater","doi":"10.1117/12.2191641","DOIUrl":"https://doi.org/10.1117/12.2191641","url":null,"abstract":"Metasurfaces composed of sub-wavelength artificial structures show promise for extraordinary light-manipulation and development of ultrathin optical components such as lenses, wave plates, orbital angular detection, and holograms over a broad range of the electromagnetic spectrum. However structures developed to date do not allow for post-fabrication control of antenna properties. We have investigated the integration of the transparent conductor indium tin oxide (ITO) active elements to realize gate-tunable phased arrays of subwavelength patch antenna in a metasurface configuration to enable gate tunable permittivity. The magnetic dipole resonance of each patch antenna interacts with the carrier density-dependent permittivity resonance of the ITO to enable phase and amplitude tunability. Operation of patch antennas and beam steering phased arrays will be discussed.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127655335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Resonant nanostructures made of high-refractive index dielectric materials offer a new way for manipulation of light at nanoscale. Due to their inherently high magnetic and electric resonant response and low losses at optical frequencies these nanostructures offers unique functionalities, which are not achievable with conventional nanoscale plasmonics. Simple examples are strong magnetic near-field enhancement and directional scattering by nanoparticles of spherical shape, also known as a Kerker’s effect. In this talk, I will review this new rapidly developing research direction and present several new results of our team, which demonstrate a huge potential of dielectric nanoantennas for various applications. Fist will be experimental demonstration of highly localized magnetic and electric fields in silicon nanodimer antennas, which can be excited at any polarization of incoming light. Second will show low-loss light propagation in silicon nanoparticle waveguides, which can be much longer than in plasmonic waveguide of similar dimensions. Finally I will present how the light can be manipulated with almost fully transparent resonant dielectric metasurfaces having a full 2π control over the phase of incoming light at visible and near-IR wavelengths.
{"title":"Light manipulation by resonant dielectric nanostructures and metasurfaces (Presentation Recording)","authors":"A. Kuznetsov","doi":"10.1117/12.2187942","DOIUrl":"https://doi.org/10.1117/12.2187942","url":null,"abstract":"Resonant nanostructures made of high-refractive index dielectric materials offer a new way for manipulation of light at nanoscale. Due to their inherently high magnetic and electric resonant response and low losses at optical frequencies these nanostructures offers unique functionalities, which are not achievable with conventional nanoscale plasmonics. Simple examples are strong magnetic near-field enhancement and directional scattering by nanoparticles of spherical shape, also known as a Kerker’s effect. In this talk, I will review this new rapidly developing research direction and present several new results of our team, which demonstrate a huge potential of dielectric nanoantennas for various applications. Fist will be experimental demonstration of highly localized magnetic and electric fields in silicon nanodimer antennas, which can be excited at any polarization of incoming light. Second will show low-loss light propagation in silicon nanoparticle waveguides, which can be much longer than in plasmonic waveguide of similar dimensions. Finally I will present how the light can be manipulated with almost fully transparent resonant dielectric metasurfaces having a full 2π control over the phase of incoming light at visible and near-IR wavelengths.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121852601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Ren, Bowen Liu, Xu Yao, Shu Chen, Liang Zhang, Lei Wang, Zhilin Yang
Compared with some precise nanofabrication methods, such as EBL and FIB, holographic lithography (HL) is a convenient way to fabricate periodic structures in a large area and with superb uniformity. In this work, we developed the deep UV HL with 266 nm laser to obtain structure with a periodicity between 100 nm to 1μm, which cannot be achieved by traditional photolithography. We further developed a strategy to fabricate hybrid periodical dimmer arrays by deep UV HL and lift-off process, followed by selectively surface functionalization. Thermal treatment was employed to as an effective approach to tune the gap size, which provides an additionally adjustable factor. By coating the substrate with gold and the obtained nanostructures with gold or silver, we have obtained periodic plasmonic structure with excellent figure of merit based on refractive index change and strong and uniform SER activity. Such a hybrid periodical dimmer arrays can be used as an effective plasmonics structure, and have potential application as a platform for high-efficiency surface- and bio- analysis.
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Science thrives on analogies, and a considerable number of inventions and discoveries have been made by pursuing an unexpected connection to a very different field of inquiry. For example, photonic crystals have been referred to as “semiconductors of light” because of the far-reaching analogies between electron propagation in a crystal lattice and light propagation in a periodically modulated photonic environment. However, two aspects of electron behavior, its spin and helicity, escaped emulation by photonic systems until recent invention of photonic topological insulators (PTIs). The impetus for these developments in photonics came from the discovery of topologically nontrivial phases in condensed matter physics enabling edge states immune to scattering. The realization of topologically protected transport in photonics would circumvent a fundamental limitation imposed by the wave equation: inability of reflections-free light propagation along sharply bent pathway. Topologically protected electromagnetic states could be used for transporting photons without any scattering, potentially underpinning new revolutionary concepts in applied science and engineering. I will demonstrate that a PTI can be constructed by applying three types of perturbations: (a) finite bianisotropy, (b) gyromagnetic inclusion breaking the time-reversal (T) symmetry, and (c) asymmetric rods breaking the parity (P) symmetry. We will experimentally demonstrate (i) the existence of the full topological bandgap in a bianisotropic, and (ii) the reflectionless nature of wave propagation along the interface between two PTIs with opposite signs of the bianisotropy.
{"title":"Guiding electromagnetic waves around sharp corners: topologically protected photonic transport in meta-waveguides (Presentation Recording)","authors":"G. Shvets, A. Khanikaev, Tzuhsuan Ma, K. Lai","doi":"10.1117/12.2189717","DOIUrl":"https://doi.org/10.1117/12.2189717","url":null,"abstract":"Science thrives on analogies, and a considerable number of inventions and discoveries have been made by pursuing an unexpected connection to a very different field of inquiry. For example, photonic crystals have been referred to as “semiconductors of light” because of the far-reaching analogies between electron propagation in a crystal lattice and light propagation in a periodically modulated photonic environment. However, two aspects of electron behavior, its spin and helicity, escaped emulation by photonic systems until recent invention of photonic topological insulators (PTIs). The impetus for these developments in photonics came from the discovery of topologically nontrivial phases in condensed matter physics enabling edge states immune to scattering. The realization of topologically protected transport in photonics would circumvent a fundamental limitation imposed by the wave equation: inability of reflections-free light propagation along sharply bent pathway. Topologically protected electromagnetic states could be used for transporting photons without any scattering, potentially underpinning new revolutionary concepts in applied science and engineering. I will demonstrate that a PTI can be constructed by applying three types of perturbations: (a) finite bianisotropy, (b) gyromagnetic inclusion breaking the time-reversal (T) symmetry, and (c) asymmetric rods breaking the parity (P) symmetry. We will experimentally demonstrate (i) the existence of the full topological bandgap in a bianisotropic, and (ii) the reflectionless nature of wave propagation along the interface between two PTIs with opposite signs of the bianisotropy.","PeriodicalId":432358,"journal":{"name":"SPIE NanoScience + Engineering","volume":"88 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122697137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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