One-dimensional Photonic Crystal Films Research Articles

Wavelength-dependent Goos-Hänchen shifts observed in one-dimensional photonic crystal films with different structures

The wavelength modulation method is innovatively adopted to measure the enhanced Goos-Hänchen (GH) shift in one-dimensional photonic crystal (1DPC) instead of typical angular modulation method. Experimental results of two samples show that dramatic effect of the photonic bandgap of different PC films on the reflection coefficient can lead to the large GH shift on several special wavelengths. The large GH shifts at different wavelengths could reveal the structure of films more clearly. The wavelength modulation method will provide a new direction for GH shift sensing and reduce the uncertainty of the calculated results in the measurement of film parameters.

Angle-Insensitive Transmission and Reflection of Nanopatterned Dielectric Multilayer Films for Colorful Solar Cells

Aesthetically appealing photovoltaic (PV) panels with colorful layers are used in numerous applications involving color matching with the surroundings. To develop a colored film for a PV system, appropriate optical properties such as high transparency and low angle sensitivity are necessary because the colored layers can reduce the efficiency of the PV system by causing variations in the transmittance and angle of incidence. Herein, we propose a facile fabrication method for bioinspired three-dimensional (3D) photonic crystal (PC) films that exhibit broad angle-insensitive transmission and reflection, for application in colorful PV. This structure, patterned on a sequentially stacked 11-layer film of SiO2 and TiO2, is fabricated via nanoimprint lithography and a one-step dry-etching process, without using a metal mask. The changes in transmission and reflection are observed via ultraviolet-visible spectroscopy and from the reflected images obtained under various angles. The transmittance dips of the 3D PC film shift by less than 10 nm in wavelength, for angles from 0 to 45°, indicating low angle dependency. In addition, the change in the observed color, with respect to the viewing position, is less in the fabricated film. Once the 3D PC film was added to a commercial PV cell, it exhibited a higher efficiency (approximately 6% upper) when compared to a cell with a one-dimensional PC film, during the duration of the experiment, from 0 to 30°. Thus, the proposed method demonstrates excellent potential for developing structural color films for achieving aesthetically appealing PV cells.

All nanoparticle-based P(MMA–AA)/TiO2 one-dimensional photonic crystal films with tunable structural colors

All nanoparticle-based P(MMA–AA)/TiO2 1DPCs with functional structural colors were fabricated using an aqueous-based and environmentally friendly spin-assisted LbL process.

聚乙二醇/二氧化钛一维光子晶体的制备及其性质研究

Multilayer polyethylene glycol / titanium dioxide( PEG / TiO2) one-dimensional photonic crystal films were fabricated by using spin coating technique. PEG / TiO2one-dimensional photonic crystal membranes with different photonic stopbands were fabricated by changing the time of spin coating,spin speed and the mass concentration of polyethylene glycol solution. The experiment results show that PEG / TiO2 film has a dual response to dimethyl sulfoxide( DMSO) and strong alkali solution.

Air waveguide in a hybrid 1D and 2D photonic crystal hetero-structure

An air waveguide in hybrid one-dimensional photonic crystal and two-dimensional photonic crystal slab hetero-structure is designed. Light propagating in air waveguide can be confined by two-dimensional photonic crystal slab in x– y plane and one-dimensional photonic crystal films in z direction. Theoretical calculations show that air waveguide in the hetero-structure can achieve some functions as 3D PhCs but could be made more easily than 3D PhCs.