Verification and improvement of equivalent refractive index models for evaluating the shielding effectiveness of high-transmittance double-layer metallic meshes

This paper first presents a switchable photonic nanojet (PNJ) generated by a polystyrene (PS) microsphere immersed in nematic liquid crystals (NLCs). The PNJ is switched by applying external voltage, which originates from the refractive index change in the surrounding medium caused by the field-induced realignment of liquid crystal molecules. By tuning the refractive index of NLCs larger or smaller than that of the PS microsphere, the PNJ can be switched off or on. Moreover, we present an optimization study to seek a better electric energy focusing property of the PNJ. Our results reveal that the switchability of PNJ can be optimized by applying a shorter incident wavelength, a double-layer microsphere, and a PS ellipsoid. The full width at half-maximum (FWHM) generated by the PS ellipsoid is narrower than that generated by the microsphere with a shorter incident wavelength. The intensity contrast of the PS ellipsoid is higher than that of the double-layer microsphere. As a whole, the switchability of PNJ can be best optimized by a PS ellipsoid. This should open the way for the development of integrated photonic devices.

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A hydrophobic and abrasion-resistant MgF2coating with an ultralow refractive index for double-layer broadband antireflective coatings

Journal of Materials Chemistry C ◽

10.1039/c6tc05307f ◽

2017 ◽

Vol 5 (12) ◽

pp. 3088-3096 ◽

Cited By ~ 12

Author(s):

Xinmin Cui ◽

Ruimin Ding ◽

Mengchao Wang ◽

Conghui Wang ◽

Jing Zhang ◽

...

Keyword(s):

Refractive Index ◽

Double Layer ◽

Abrasion Resistance ◽

Sol Gel ◽

Antireflective Coatings

A novel sol–gel route was proposed in order to prepare an ultralow-index MgF2coating with both hydrophobicity and good abrasion-resistance.

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High Polaried Transmission Effects for Double-Layer Metallic Grating Films on GaN Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.295-297.1289 ◽

2011 ◽

Vol 295-297 ◽

pp. 1289-1293

Author(s):

Bing Cao ◽

Gui Ju Zhang ◽

Qin Han ◽

Chin Hua Wang ◽

Jian Feng Wang ◽

...

Keyword(s):

Refractive Index ◽

Double Layer ◽

Transition Layer ◽

Light Transmission ◽

Light Emitting Diode ◽

Extinction Ratio ◽

Polarized Light ◽

Incident Wavelength ◽

Metallic Grating ◽

Low Refractive Index

Highly polarized light transmission from GaN based light emitting diode is proposed using a double-layer metallic grating film and a dielectric transition layer. TM mode transmission and the polarized extinction ratio (ER) are calculated using commercial software, based on a full vector implementation of Rigorous Coupled Wave Analysis (RCWA) algorithm. Such a thin-film double-layer grating with subwavelength metallic stripes are designed and simulated by perfect parameters of period, thickness and filling factor for achieving good polarization properties. It is found that TM transmission and ER are almost stable and flat under different slit arrays of the double-layer grating. The polarized structure shows larger width of incident wavelength with a transition layer of a low refractive index than that of a high refractive index, but higher TM transmission and ER can be obtained for low refractive index transition layer. Flat sensitivity and high transmission of the TM mode on the double-layer metal grating thickness have been achieved. Up to 100nm range of the grating height can be employed to achieve TM transmission more than 92% while ER> 20dB. The results provide guidance in designing, optimizing and fabricating the integrated GaN-based and polarized photonic devices.

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