scholarly journals Theoretical Comparison of Optothermal Absorption in Transmissive Metalenses Composed of Nanobricks and Nanoholes

Photonics ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 39
Author(s):  
Feng Tang ◽  
Qingzhi Li ◽  
Haichao Yu ◽  
Zao Yi ◽  
Xin Ye
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Field Enhancement ◽  
Optical Systems ◽  
Optical Components ◽  
Theoretical Comparison ◽  
Unit Cells ◽  
The Mean ◽  
Intense Light

Background: Optical components with high damage thresholds are very desirable in intense-light systems. Metalenses, being composed of phase-control nanostructures with peculiar properties, are one of the important component candidates in future optical systems. However, the optothermal mechanism in metalenses is still not investigated adequately. Methods: In this study, the optothermal absorption in transmissive metalenses made of silicon nanobricks and nanoholes is investigated comparatively to address this issue. Results: The geometrical dependencies of nanostructures’ transmittance, phase difference, and field distribution are calculated numerically via simulations. To demonstrate the optothermal mechanism in metalenses, the mean absorption efficiencies of the selected unit-cells, which would constitute metalenses, are analyzed. The results show that the electric field in the silicon zone would lead to an obvious thermal effect, and the enhancement of the localized electric field also results in the strong absorption of optical energy. Then, two typical metalenses are designed based on these nanobricks and nanoholes. The optothermal simulations show that the nanobrick-based metalens can handle a power density of 0.15 W/µm2, and the density of the nanohole-based design is 0.12 W/µm2. Conclusions: The study analyzes and compares the optothermal absorption in nanobricks and nanoholes, which shows that the electric-field distribution in absorbent materials and the localized-field enhancement are the two key effects that lead to optothermal absorption. This study provides an approach to improve the anti-damage potentials of transmissive metalenses for intense-light systems.

Tuning the Localized Surface Plasmon Resonance of Al-Al2O3 Nanosphere Towards NIR Region by Gold Coating

2020 ◽  
Vol 12 ◽  
Author(s):  
Jyoti Katyal ◽  
Shivani Gautam
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Dielectric Layer ◽  
Electric Field Distribution ◽  
Active Material ◽  
Visible Region ◽  
Field Enhancement ◽  
Localized Surface Plasmon ◽  
Sers Substrate ◽  
Al Nanoparticles

Background: A relatively narrow LSPR peak and a strong inter band transition ranging around 800 nm makes Al strongly plasmonic active material. Usually, Al nanoparticles are preferred for UV-plasmonic as the SPR of small size Al nanoparticles locates in deep UV-UV region of the optical spectrum. This paper focused on tuning the LSPR of Al nanostructure towards infrared region by coating Au layer. The proposed structure has Au as outer layer which prevent the further oxidation of Al nanostructure. Methods: The Finite Difference Time Domain (FDTD) and Plasmon Hybridization Theory has been used to evaluated the LSPR and field enhancement of single and dimer Al-Al2O3-Au MDM nanostructure. Results: It is observed that the resonance mode show dependence on the thickness of Al2O3 layer and also on the composition of nanostructure. The Au layered MDM nanostructure shows two peak of equal intensities simultaneously in UV and visible region tuned to NIR region. The extinction spectra and electric field distribution profiles of dimer nanoparticles are compared with monomer to reveal the extent of coupling. The dimer configuration shows higher field enhancement ~107 at 1049 nm. By optimizing the thickness of dielectric layer the MDM nanostructure can be used over UV-visible-NIR region. Conclusion: The LSPR peak shows dependence on the thickness of dielectric layer and also on the composition of nanostructure. It has been observed that optimization of size and thickness of dielectric layer can provide two peaks of equal intensities in UV and Visible region which is advantageous for many applications. The electric field distribution profiles of dimer MDM nanostructure enhanced the field by ~107 in visible and NIR region shows its potential towards SERS substrate. The results of this study will provide valuable information for the optimization of LSPR of Al-Al2O3-Au MDM nanostructure to have high field enhancement.

Electric field distribution of Ag@CuO and Ag@ZnO core–shell dimer

2021 ◽  
Vol 35 (12) ◽  
pp. 2150203
Author(s):  
Guoli Li ◽  
Haixia Chen ◽  
Jijun Ding
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Shell Thickness ◽  
Electric Field Distribution ◽  
Field Enhancement ◽  
Shell Structures ◽  
Core Shell ◽  
Enhancement Effect ◽  
Surface Plasma ◽  
Surface Plasma Resonance

The effect of shape, material and shell thickness on electric field distribution of both Ag@CuO and Ag@ZnO core–shell dimer is investigated. First, three core–shell structures, including plane@circle, triangle@circle and quadrilateral@circle are designed. The field enhancement advantages of the quadrilateral@circle structures are summarized by analyzing the electric field distribution diagrams. Then the influence of materials on the field enhancement effect of core–shell dimer is discussed. The results show that Ag@CuO structure has better stability, while Ag@ZnO structure have larger electric field enhancement. Finally, the shell thickness is changed from 0.1 nm to 1.5 nm. We found that the X-component electric field of both the Ag@ZnO and Ag@CuO core–shell dimer structure is decreased with the increase in the shell thickness. Also, the X-component electric field of Ag@ZnO core–shell dimer is about five times than that of the Ag@CuO. The increase of electric field indicated that Ag@ZnO core–shell dimer has strong local surface plasma resonance characteristics.

scholarly journals Construction of a femtosecond laser for the study of aberrations in optical systems

2013 ◽  
Vol 23 ◽  
pp. 7-11
Author(s):  
Miguel Ángel González Galicia ◽  
M. Rosete-Aguilar ◽  
N. C. Bruce ◽  
J. Garduño-Mejía ◽  
R. Ortega-Martínez
Keyword(s):  
Femtosecond Laser ◽  
Electric Field ◽  
Field Distribution ◽  
Focal Plane ◽  
Electric Field Distribution ◽  
Laser System ◽  
Optical Systems ◽  
Sapphire Crystal ◽  
Field Curvature ◽  
Theoretical Results

We present the construction of a femtosecond laser, based on a titanium sapphire crystal. This laser produce pulses of 20 fs. We also present theoretical results for the electric field distribution near the focal plane of a lens for gaussian illumination under the influence of primary aberrations: spherical aberrations, coma, astigmatism and field curvature, for an achromatic doublet. The theoretical results are compared with results obtained with the laser system constructed.

Effect of Void Shape in Polymeric Insulator on the Electric Field Distribution

2017 ◽  
Vol 5 (3) ◽  
pp. 96
Author(s):  
I. Made Yulistya Negara ◽  
Dimas Anton Asfani ◽  
Daniar Fahmi ◽  
Yusrizal Afif
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Void Shape

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

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