scholarly journals Integration of bio-responsive silver in 1D photonic crystals: towards the colorimetric detection of bacteria

2020 ◽  
Vol 223 ◽  
pp. 125-135 ◽  
Author(s):  
Giuseppe M. Paternò ◽  
Liliana Moscardi ◽  
Stefano Donini ◽  
Aaron M. Ross ◽  
Silvia M. Pietralunga ◽  
...  

Colorimetric read-out of a silver/1D photonic crystal upon exposure to E. coli.

MRS Bulletin ◽  
2001 ◽  
Vol 26 (8) ◽  
pp. 623-626 ◽  
Author(s):  
R.B. Wehrspohn ◽  
J. Schilling

In the last few years, photonic crystals have gained considerable interest due to their ability to “mold the flow of light.” Photonic crystals are physically based on Bragg reflections of electromagnetic waves. In simple terms, a one-dimensional (1D) photonic crystal is a periodic stack of thin dielectric films with two different refractive indices, n1 and n2. The two important geometrical parameters determining the wavelength of the photonic bandgap are the lattice constant, a = d1(n1) + d2(n2), and the ratio of d1 to a (where d1 is the thickness of the layer with refractive index n1, and d2 is the thickness of layer n2). For a simple quarter-wavelength stack, the center wavelength λ of the 1D photonic crystal would be simply λ = 2n1d1 + 2n2d2. In the case of 2D photonic crystals, the concept is extended to either airholes in a dielectric medium or dielectric rods in air. Therefore, ordered porous dielectric materials like porous silicon or porous alumina are intrinsically 2D photonic crystals.


Nanoscale ◽  
2017 ◽  
Vol 9 (35) ◽  
pp. 12969-12975 ◽  
Author(s):  
Xiang Fei ◽  
Tao Lu ◽  
Jun Ma ◽  
Shenmin Zhu ◽  
Di Zhang

Photonic crystals with both optical and thermal responses based on a natural butterfly wing template.


2020 ◽  
pp. 2000317
Author(s):  
Weiqiang Xie ◽  
Peter Verheyen ◽  
Marianna Pantouvaki ◽  
Joris Van Campenhout ◽  
Dries Van Thourhout

2008 ◽  
Vol 1133 ◽  
Author(s):  
Brian T. Cunningham ◽  
Leo Chan ◽  
Patrick C. Mathias ◽  
Nikhil Ganesh ◽  
Sherine George ◽  
...  

Abstract Photonic crystal surfaces represent a class of resonant optical structures that are capable of supporting high intensity electromagnetic standing waves with near-field and far-field properties that can be exploited for high sensitivity detection of biomolecules and cells. While modulation of the resonant wavelength of a photonic crystal by the dielectric permittivity of adsorbed biomaterials enables label-free detection, the resonance can also be tuned to coincide with the excitation wavelength of common fluorescent tags - including organic molecules and semiconductor quantum dots. Photonic crystals are also capable of efficiently channeling fluorescent emission into a preferred direction for enhanced extraction efficiency. Photonic crystals can be designed to support multiple resonant modes that can perform label free detection, enhanced fluorescence excitation, and enhanced fluorescence extraction simultaneously on the same device. Because photonic crystal surfaces may be inexpensively produced over large surface areas by nanoreplica molding processes, they can be incorporated into disposable labware for applications such as pharmaceutical high throughput screening. In this talk, the optical properties of surface photonic crystals will be reviewed and several applications will be described, including results from screening a 200,000-member chemical compound library for inhibitors of protein-DNA interactions, gene expression microarrays, and high sensitivity of protein biomarkers.


2007 ◽  
Vol 2007 ◽  
pp. 1-8
Author(s):  
Xiaoshuang Chen ◽  
Renlong Zhou ◽  
Yong Zeng ◽  
Hongbo Chen ◽  
Wei Lu

We review the simulation work for the far-field focus and dispersionless anticrossing bands in two-dimensional (2D) photonic crystals. In a two-dimensional photonic-crystal-based concave lens, the far-field focus of a plane wave is given by the distance between the focusing point and the lens. Strong and good-quality far-field focusing of a transmitted wave, explicitly following the well-known wave-beam negative refraction law, can be achieved. The spatial frequency information of the Bloch mode in multiple Brillouin zones (BZs) is investigated in order to indicate the wave propagation in two different regions. When considering the photonic transmission in a 2D photonic crystal composed of a negative phase-velocity medium (NPVM), it is shown that the dispersionless anticrossing bands are generated by the couplings among the localized surface polaritons of the NPVM rods. The photonic band structures of the NPVM photonic crystals are characterized by a topographical continuous dispersion relationship accompanied by many anticrossing bands.


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