Near-field thermal radiation of gradient refractive index slab: Internal polaritons

2021 ◽  
Vol 119 (14) ◽  
pp. 141106
Author(s):  
Deyu Xu ◽  
Junming Zhao ◽  
Linhua Liu
Keyword(s):  
Refractive Index ◽  
Thermal Radiation ◽  
Near Field ◽  
Gradient Refractive Index

Two-Dimensional Hybrid Photonic Crystal With Graded Low-Index Using a Nonuniform Voltage

2019 ◽  
Vol 75 (1) ◽  
pp. 65-71
Author(s):  
Behrooz Rezaei ◽  
Ibrahim Halil Giden ◽  
Mohammad Sadegh Zakerhamidi ◽  
Amid Ranjkesh ◽  
Tae-Hoon Yoon
Keyword(s):  
Refractive Index ◽  
Liquid Crystal ◽  
Photonic Crystal ◽  
Light Propagation ◽  
Near Field ◽  
Refractive Index Profile ◽  
Index Structure ◽  
Focal Distance ◽  
Graded Index ◽  
Gradient Refractive Index

AbstractWe proposed a new method for designing graded index lens using liquid crystal infiltration into annular photonic crystals. Applying an external nonuniform voltage in the transverse direction perpendicular to the direction of light propagation yields different orientation of liquid crystal molecules inside the photonic crystal unit cells. As a result, a gradient refractive index was modulated. We numerically investigate focusing properties of the designed graded index structure using plane-wave expansion and finite-difference time-domain methods. The gradient refractive index profile was adjusted by varying the nonuniform voltage excitations, which consequently altered the focal distance of the graded index structure. A wide tuning range of 1856 nm was achieved for focal distance by the proposed graded index structure. This feature can be implemented for planning a flat lens with tunable focal distance based on electro-optic effect. These achievements may have future applications in some optical devices such as near-field imaging and scanning.

scholarly journals Optical Sensitivity of Waveguides Inscribed in Nanoporous Silicate Framework

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 123
Author(s):  
Zhong Lijing ◽  
Roman A. Zakoldaev ◽  
Maksim M. Sergeev ◽  
Andrey B. Petrov ◽  
Vadim P. Veiko ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Field ◽  
Experimental Studies ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Direct Writing ◽  
Sensor Applications ◽  
Refractive Index Contrast ◽  
Optical Sensitivity ◽  
Index Contrast

Laser direct writing technique in glass is a powerful tool for various waveguides’ fabrication that highly develop the element base for designing photonic devices. We apply this technique to fabricate waveguides in porous glass (PG). Nanoporous optical materials for the inscription can elevate the sensing ability of such waveguides to higher standards. The waveguides were fabricated by a single-scan approach with femtosecond laser pulses in the densification mode, which resulted in the formation of a core and cladding. Experimental studies revealed three types of waveguides and quantified the refractive index contrast (up to Δn = 1.2·10−2) accompanied with ~1.2 dB/cm insertion losses. The waveguides demonstrated the sensitivity to small objects captured by the nanoporous framework. We noticed that the deposited ethanol molecules (3 µL) on the PG surface influence the waveguide optical properties indicating the penetration of the molecule to its cladding. Continuous monitoring of the output near field intensity distribution allowed us to determine the response time (6 s) of the waveguide buried at 400 µm below the glass surface. We found that the minimum distinguishable change of the refractive index contrast is 2 × 10−4. The results obtained pave the way to consider the waveguides inscribed into PG as primary transducers for sensor applications.

Near-field and far-field effects in thermal radiation from metallic carbon nanotubes

2007 ◽  
Author(s):  
Andrei M. Nemilentsau ◽  
Gregory Ya. Slepyan ◽  
Sergey A. Maksimenko
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Radiation ◽  
Near Field ◽  
Far Field ◽  
Field Effects

Gradient refractive-index optical rod prepared from methacrylate derivatives

1997 ◽  
Vol 22 (10) ◽  
pp. 668 ◽  
Author(s):  
Jui-Hsiang Liu ◽  
Hung-Tsai Liu
Keyword(s):  
Refractive Index ◽  
Gradient Refractive Index

Hybrid Polymers for Gradient Refractive Index Lens

2021 ◽  
Author(s):  
Omena Okpowe ◽  
Andriy Durygin ◽  
Vadym Drozd ◽  
Temitayo Olowu ◽  
Nezih Pala ◽  
...  
Keyword(s):  
Refractive Index ◽  
Hybrid Polymers ◽  
Gradient Refractive Index

scholarly journals The Polymerization of MMA and ST to Prepare Material with Gradient Refractive Index in Electric Field

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Yao Huang ◽  
Daming Wu ◽  
Dongyun Ren ◽  
Qingyun Meng ◽  
Xiaojun Di
Keyword(s):  
Molecular Weight ◽  
Refractive Index ◽  
Electric Field ◽  
Cylindrical Sample ◽  
Electrical Field ◽  
Molecular Weights ◽  
The Matrix ◽  
Gradient Refractive Index ◽  
Scattering Material ◽  
Different Parts

Light scattering material with gradient refractive index was prepared under the electrical field by taking methyl methacrylate (MMA) monomer as the matrix with the addition of a little preheated styrene (ST) and peroxidation benzoin formyl (BPO). The material obtained under electrical field presented different transmittance and molecular weight at different parts of the cylindrical sample along the axis of the direction of electric field which led to the layering phenomenon and gradient refractive index. The disparity of molecular weight between different layers can be as much as 230 thousand. There were several peaks in the figure of GPC test of the sample under electric field. This proved that there were polymers with different molecular weights in the sample. Therefore, it can be concluded that electrical field has a significant effect on polymerization.

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