Nicklas Anttu
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Deep Sub-Wavelength 3D Imaging Using a Single Nanowire Detector Open
Nanowires have an ideal shape for high-resolution imaging, with a small cross-section for high resolution and a long length for strong absorption. However, since the absorption in nanowires is dominated by nanophotonic effects, it is uncle…
Fluorophore signal detection and imaging enhancement in high refractive index nanowire biosensors Open
Semiconductor nanowires are an efficient platform for fluorescence-based biosensors. Here, we model how a GaP nanowire (i) enhances the excitation intensity at the position of the fluorophore attached to the nanowire sidewall, (ii) enhance…
Image analysis optimization for nanowire-based optical detection of molecules Open
Semiconductor nanowires can enhance the signal of fluorescent molecules, thus significantly improving the limits of fluorescence detection in optical biosensing. In this work, we explore how the sensitivity can further be enhanced through …
Chiro-Optical Structures with Magnetizable Plasmonic Elements for Modulating the Chiral Transmission of Light Open
Manipulating external stimuli is crucial for enhancing and controlling the optical response in chiral structures. This study introduces chiral structures composed of single, dimer, or trimer arrays of plasmonic and magneto-plasmonic trapez…
Fluorophore signal detection and imaging enhancement in high refractive index nanowire biosensors Open
High refractive index semiconductor nanowires have recently been demonstrated experimentally as an efficient platform for enhancing the signal in fluorescence-based biosensors. Here, we study through modelling how a vertical GaP nanowire (…
Optimized absorption of light in perovskite nanowire solar cells Open
Metal halide perovskite nanowires (PrvNWs) have recently emerged as an interesting path for nanostructured solar cells. Here, we model the absorption of light in PrvNW arrays for varying diameter and length of the PrvNWs and period for the…
Analysis of Nanowire pn-Junction with Combined Current–Voltage, Electron-Beam-Induced Current, Cathodoluminescence, and Electron Holography Characterization Open
We present the characterization of a pn-junction GaAs nanowire. For the characterization, current–voltage, electron-beam-induced current, cathodoluminescence, and electron holography measurements are used. We show that by combining informa…
Wide angle anapole excitation in stacked resonators Open
In the search for resonances with high localized field strengths in all-dielectric nanophotonics, novel states such as anapoles, hybrid anapoles and bound states in the continuum have been realized. Of these, the anapoles are the most read…
Beyond ray optics absorption of light in CsPbBr<sub>3</sub> perovskite nanowire arrays studied experimentally and with wave optics modelling Open
We study experimentally and with wave optics modelling the absorption of light in CsPbBr 3 perovskite nanowire arrays fabricated into periodic pores of an anodized aluminum oxide matrix, for nanowire diameters from 30 to 360 nm. First, we …
Optimized Absorption of Light in Perovskite Nanowire Solar Cells Open
Metal halide perovskite nanowires (PrvNWs) have recently emerged as an interesting path for nanostructured solar cells. Here, we model the absorption of light in PrvNW arrays for varying diameter and length of the PrvNWs and period for the…
Absorption of Light in Vertical III-V Semiconductor Nanowires for Solar Cell and Photodetector Applications Open
Vertical III-V semiconductor nanowires have shown promising absorption of light for solar cell and photodetector applications. The absorption properties can be tuned through the choice of III-V materials and geometry of the nanowires. Here…
Absorption of Light in Vertical III-V Semiconductor Nanowires for Solar Cell and Photodetector Applications Open
Vertical III-V semiconductor nanowires have shown promising absorption of light for solar cell and photodetector applications. The absorption properties can be tuned through the choice of III-V materials and geometry of the nanowires. Here…
Absorption of Light in Vertical III-V Semiconductor Nanowires for Solar Cell and Photodetector Applications Open
Vertical III-V semiconductor nanowires have shown promising absorption of light for solar cell and photodetector applications. The absorption properties can be tuned through the choice of III-V materials and geometry of the nanowires. Here…
Electro-Optical Coupling in Double Diode Structures Open
Funding Information: The authors acknowledge the provision of facilities and technical support by Aalto University at Micronova Nanofabrication Centre, Professor M. Guina for the MBE samples, and Dr Janne Halme for access and training to t…
Modeling selective narrowband light absorption in coaxial InAs-GaAs<sub>0.1</sub>Sb<sub>0.9</sub> nanowires with partial shell segment coverage Open
Vertical III-V nanowire (NW) arrays are promising candidates for infrared (IR) photodetection applications. Generally, NWs with large diameters are required for efficient absorption in the IR range. However, increasing the NW diameter resu…
Fluorescence excitation enhancement by waveguiding nanowires Open
Fluorescence excitation enhancement is important for biosensing; we for the first time study it quantitatively for GaP NWs.
Falling beads on a falling rod Open
The falling rod paradox, i.e. the fact that the tip of an almost horizontal rod falls with an acceleration ‘higher than g ’, when the other end is hinged or supported, is a popular physics demonstration. It can be visualized by placing e.g…
Enhanced Optical Biosensing by Aerotaxy Ga(As)P Nanowire Platforms Suitable for Scalable Production Open
Sensitive detection of low-abundance biomolecules is central for diagnostic applications. Semiconductor nanowires can be designed to enhance the fluorescence signal from surface-bound molecules, prospectively improving the limit of optical…
Designing outcoupling of light from nanostructured emitter in stratified medium with parasitic absorption Open
We demonstrate dipole-based modeling for designing nanostructured emitters in a stratified surrounding medium in the presence of parasitic absorption, while giving equivalent information about far-field emission as Lorentz reciprocity. We …
Absorption of Light in Finite Semiconductor Nanowire Arrays and the Effect of Missing Nanowires Open
When modelling the absorption in semiconductor nanowire (NW) arrays for solar cell and photodetector applications, the array is typically assumed to be infinitely periodic such that a single unit cell suffices for the simulations. However,…
Wafer-Scale Synthesis and Optical Characterization of InP Nanowire Arrays for Solar Cells Open
Nanowire solar cells have the potential to reach the same efficiencies as the world-record III-V solar cells while using a fraction of the material. For solar energy harvesting, large-area nanowire solar cells have to be processed. In this…
Symmetry Reduction in FEM Optics Modeling of Single and Periodic Nanostructures Open
Numerical optics modeling is an invaluable tool in the design of nanostructures for nanophotonics applications where diffraction effects often lead to complex dependency between the nanostructure geometry and its optical properties and res…
Applied electromagnetic optics simulations for nanophotonics Open
Nanophotonics—the science and technology of confining, guiding, and making photons interact with matter at the nanoscale—is an active research field. By varying the geometry and constituent materials, nanostructures allow precise control o…
Nanowire Oligomer Waveguide Modes towards Reduced Lasing Threshold Open
Semiconductor nanowires offer a promising route of realizing nanolasers for the next generation of chip-scale optoelectronics and photonics applications. Established fabrication methods can produce vertical semiconductor nanowires which ca…
Comparison of absorption simulation in semiconductor nanowire and nanocone arrays with the Fourier modal method, the finite element method, and the finite-difference time-domain method Open
For the design of nanostructured semiconductor solar cells and photodetectors, optics modelling can be a useful tool that reduces the need of time-consuming and costly prototyping. We compare the performance of three of the most popular nu…
Management of light and scattering in InP NWs by dielectric polymer shell Open
Understanding and management of light is of great importance for nanoscale devices. This report demonstrates enhanced absorption, photoluminescence and scattering in InP nanowires when coated with dielectric polymer shell. The shells incre…
Geometry Tailoring of Emission from Semiconductor Nanowires and Nanocones Open
Semiconductor nanowires are of interest as light emitters in applications such as light-emitting diodes and single-photon sources. Due to the three-dimensional geometry in combination with a size comparable to the wavelength of the emitted…
Optical far-field extinction of a single GaAs nanowire towards in situ size control of aerotaxy nanowire growth Open
A substrate-free approach of semiconductor nanowire growth has been achieved by the aerotaxy technique previously. In this work, we propose an in situ method to monitor the size of nanowires through non-destructive optical-extinction measu…
Absorption modeling with FMM, FEM and FDT Open
Absorption modeling is at the core of the design process of nanostructured solar cells and photodetectors. We compare the performance of three of the most popular numerical modeling methods: the Fourier modal method (FMM), the finite eleme…
Tailored emission to boost open-circuit voltage in solar cells Open
Recently, a lot of research focus has been on how to make solar cells more efficient. One direction is to enhance the open-circuit voltage V oc by optimizing the emission of photons in the cell, where emission is a necessary loss process d…