The Experts below are selected from a list of 3393 Experts worldwide ranked by ideXlab platform
Albert Polman - One of the best experts on this subject based on the ideXlab platform.
-
Single-Step Soft-Imprinted Large-Area Nanopatterned Antireflection Coating
2015Co-Authors: Jorik Van De Groep, Pierpaolo Spinelli, Albert PolmanAbstract:We demonstrate an effective nanopatterned Antireflection Coating on glass that is based on sol–gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) Antireflection Coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance
-
mode coupling by plasmonic surface scatterers in thin film silicon solar cells
Applied Physics Letters, 2012Co-Authors: M Van Lare, Marc A Verschuuren, F O Lenzmann, Albert PolmanAbstract:We demonstrate effective mode coupling by light scattering from periodic Ag nanoparticle arrays printed onto a completed thin-film a-Si:H solar cell. Current-voltage measurements show a photocurrent enhancement of 10% compared to a flat reference cell with a standard Antireflection Coating. External quantum efficiency measurements for the nanopatterned cells show clear infrared photocurrent enhancement peaks, corresponding to coupling to discrete waveguide modes in the a-Si:H layer. The data are in good agreement with three-dimensional finite element simulations, which are used to further optimize the design. We show that broadband photocurrent enhancement can be obtained over the 450–750 nm spectral range.
-
broadband omnidirectional Antireflection Coating based on subwavelength surface mie resonators
Nature Communications, 2012Co-Authors: Pierpaolo Spinelli, Marc A Verschuuren, Albert PolmanAbstract:Minimising reflection from the interface between materials is an important goal for optical devices such as solar cells or photodetectors. Spinelli et al. show almost total loss of reflection over a broad spectral range from a silicon surface using periodic arrays of sub-wavelength silicon nanocylinders.
-
Broadband omnidirectional Antireflection Coating based on subwavelength surface Mie resonators
Nature Communications, 2012Co-Authors: Pierpaolo Spinelli, MARCUS ANTONIUS VERSCHUUREN, Albert PolmanAbstract:Reflection is a natural phenomenon that occurs when light passes the interface between materials with different refractive index. In many applications, such as solar cells or photodetectors, reflection is an unwanted loss process. Many ways to reduce reflection from a substrate have been investigated so far, including dielectric interference Coatings, surface texturing, adiabatic index matching and scattering from plasmonic nanoparticles. Here we present an entirely new concept that suppresses the reflection of light from a silicon surface over a broad spectral range. A two-dimensional periodic array of subwavelength silicon nanocylinders designed to possess strongly substrate-coupled Mie resonances yields almost zero total reflectance over the entire spectral range from the ultraviolet to the near-infrared. This new Antireflection concept relies on the strong forward scattering that occurs when a scattering structure is placed in close proximity to a high-index substrate with a high optical density of states.
Pierpaolo Spinelli - One of the best experts on this subject based on the ideXlab platform.
-
single step soft imprinted large area nanopatterned Antireflection Coating
Nano Letters, 2015Co-Authors: Jorik Van De Groep, Pierpaolo Spinelli, A PolmanAbstract:We demonstrate an effective nanopatterned Antireflection Coating on glass that is based on sol–gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) Antireflection Coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance <0.05% at 590 nm. The nanoglass Coating is made using a simple process involving only spin-Coating and an imprint step, without vacuum technology or annealing required. The refractive index of the nanoglass layers can be tailored over a broad range by controlling the geometry (1.002 < n < 1.44 in theory), covering a wide range that is not achievable with natural materials. We demonstrate that the nanoglass Coating effectively eliminates glare from smart-phone display windows and significantly improves the efficiency o...
-
Single-Step Soft-Imprinted Large-Area Nanopatterned Antireflection Coating
2015Co-Authors: Jorik Van De Groep, Pierpaolo Spinelli, Albert PolmanAbstract:We demonstrate an effective nanopatterned Antireflection Coating on glass that is based on sol–gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) Antireflection Coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance
-
broadband omnidirectional Antireflection Coating based on subwavelength surface mie resonators
Nature Communications, 2012Co-Authors: Pierpaolo Spinelli, Marc A Verschuuren, Albert PolmanAbstract:Minimising reflection from the interface between materials is an important goal for optical devices such as solar cells or photodetectors. Spinelli et al. show almost total loss of reflection over a broad spectral range from a silicon surface using periodic arrays of sub-wavelength silicon nanocylinders.
-
Broadband omnidirectional Antireflection Coating based on subwavelength surface Mie resonators
Nature Communications, 2012Co-Authors: Pierpaolo Spinelli, MARCUS ANTONIUS VERSCHUUREN, Albert PolmanAbstract:Reflection is a natural phenomenon that occurs when light passes the interface between materials with different refractive index. In many applications, such as solar cells or photodetectors, reflection is an unwanted loss process. Many ways to reduce reflection from a substrate have been investigated so far, including dielectric interference Coatings, surface texturing, adiabatic index matching and scattering from plasmonic nanoparticles. Here we present an entirely new concept that suppresses the reflection of light from a silicon surface over a broad spectral range. A two-dimensional periodic array of subwavelength silicon nanocylinders designed to possess strongly substrate-coupled Mie resonances yields almost zero total reflectance over the entire spectral range from the ultraviolet to the near-infrared. This new Antireflection concept relies on the strong forward scattering that occurs when a scattering structure is placed in close proximity to a high-index substrate with a high optical density of states.
-
optical impedance matching using coupled plasmonic nanoparticle arrays
Nano Letters, 2011Co-Authors: Pierpaolo Spinelli, Maarten Hebbink, R De Waele, Lachlan E Black, F O Lenzmann, A PolmanAbstract:Silver nanoparticle arrays placed on top of a high-refractive index substrate enhance the coupling of light into the substrate over a broad spectral range. We perform a systematic numerical and experimental study of the light incoupling by arrays of Ag nanoparticle arrays in order to achieve the best impedance matching between light propagating in air and in the substrate. We identify the parameters that determine the incoupling efficiency, including the effect of Fano resonances in the scattering, interparticle coupling, as well as resonance shifts due to variations in the near-field coupling to the substrate and spacer layer. The optimal configuration studied is a square array of 200 nm wide, 125 nm high spheroidal Ag particles, at a pitch of 450 nm on a 50 nm thick Si(3)N(4) spacer layer on a Si substrate. When integrated over the AM1.5 solar spectral range from 300 to 1100 nm, this particle array shows 50% enhanced incoupling compared to a bare Si wafer, 8% higher than a standard interference Antireflection Coating. Experimental data show that the enhancement occurs mostly in the spectral range near the Si band gap. This study opens new perspectives for Antireflection Coating applications in optical devices and for light management in Si solar cells.
A Polman - One of the best experts on this subject based on the ideXlab platform.
-
single step soft imprinted large area nanopatterned Antireflection Coating
Nano Letters, 2015Co-Authors: Jorik Van De Groep, Pierpaolo Spinelli, A PolmanAbstract:We demonstrate an effective nanopatterned Antireflection Coating on glass that is based on sol–gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) Antireflection Coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance <0.05% at 590 nm. The nanoglass Coating is made using a simple process involving only spin-Coating and an imprint step, without vacuum technology or annealing required. The refractive index of the nanoglass layers can be tailored over a broad range by controlling the geometry (1.002 < n < 1.44 in theory), covering a wide range that is not achievable with natural materials. We demonstrate that the nanoglass Coating effectively eliminates glare from smart-phone display windows and significantly improves the efficiency o...
-
optical impedance matching using coupled plasmonic nanoparticle arrays
Nano Letters, 2011Co-Authors: Pierpaolo Spinelli, Maarten Hebbink, R De Waele, Lachlan E Black, F O Lenzmann, A PolmanAbstract:Silver nanoparticle arrays placed on top of a high-refractive index substrate enhance the coupling of light into the substrate over a broad spectral range. We perform a systematic numerical and experimental study of the light incoupling by arrays of Ag nanoparticle arrays in order to achieve the best impedance matching between light propagating in air and in the substrate. We identify the parameters that determine the incoupling efficiency, including the effect of Fano resonances in the scattering, interparticle coupling, as well as resonance shifts due to variations in the near-field coupling to the substrate and spacer layer. The optimal configuration studied is a square array of 200 nm wide, 125 nm high spheroidal Ag particles, at a pitch of 450 nm on a 50 nm thick Si(3)N(4) spacer layer on a Si substrate. When integrated over the AM1.5 solar spectral range from 300 to 1100 nm, this particle array shows 50% enhanced incoupling compared to a bare Si wafer, 8% higher than a standard interference Antireflection Coating. Experimental data show that the enhancement occurs mostly in the spectral range near the Si band gap. This study opens new perspectives for Antireflection Coating applications in optical devices and for light management in Si solar cells.
Jorik Van De Groep - One of the best experts on this subject based on the ideXlab platform.
-
single step soft imprinted large area nanopatterned Antireflection Coating
Nano Letters, 2015Co-Authors: Jorik Van De Groep, Pierpaolo Spinelli, A PolmanAbstract:We demonstrate an effective nanopatterned Antireflection Coating on glass that is based on sol–gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) Antireflection Coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance <0.05% at 590 nm. The nanoglass Coating is made using a simple process involving only spin-Coating and an imprint step, without vacuum technology or annealing required. The refractive index of the nanoglass layers can be tailored over a broad range by controlling the geometry (1.002 < n < 1.44 in theory), covering a wide range that is not achievable with natural materials. We demonstrate that the nanoglass Coating effectively eliminates glare from smart-phone display windows and significantly improves the efficiency o...
-
Single-Step Soft-Imprinted Large-Area Nanopatterned Antireflection Coating
2015Co-Authors: Jorik Van De Groep, Pierpaolo Spinelli, Albert PolmanAbstract:We demonstrate an effective nanopatterned Antireflection Coating on glass that is based on sol–gel chemistry and large-area substrate-conformal soft-imprint technology. The printed 120 nm tall silica nanocylinders with a diameter of 245 nm in a square array with 325 nm pitch form an effective-index (n = 1.20) Antireflection Coating that reduces the double-sided reflection from a borosilicate glass slide from 7.35% to 0.57% (averaged over the visible spectral range) with a minimum reflectance
B Hubner - One of the best experts on this subject based on the ideXlab platform.
-
laterally tapered inp ingaasp waveguides for low loss chip to fiber butt coupling a comparison of different configurations
IEEE Photonics Technology Letters, 1995Co-Authors: R Zengerle, O Leminger, W Weiershausen, K Faltin, B HubnerAbstract:Low-loss chip to-fiber coupling can be achieved by on-chip spot-size transformers. Two simple versions using laterally tapered InP-InGaAsP waveguides at the 1.55 /spl mu/m wavelength have been fabricated: one consisting of two differently tapered layers, the other with only one taper. The influence of the taper shape and of fabrication tolerances on their performance is compared both experimentally and theoretically. The optimum insertion loss for a single transformer without Antireflection Coating, including Fresnel losses, amounts to 1.1 dB. >