Enhanced Bragg reflections from size-matched heterostructure photonic crystal thin films prepared by the Langmuir-Blodgett method

Abstract

The Langmuir-Blodgett method was used to engineer photonic crystal thin films of an AB architecture. Structures were studied by transmittance and reflectance spectroscopies. For an AB structure in which the silica particle diameter B is twice that of A, reflectance features associated with the first order Bragg peak for the "A" domain are only observed when the structure is probed from the A side of the structure. Furthermore, this feature is enhanced in intensity compared to that for a structure consisting solely of A particles. These findings are attributed to a matching of first and second order Bragg processes. (c) 2006 American Institute of Physics. (DOI:10.1063/1.2339031

A photonic heterostructure produces diverse iridescent colours in duck wing patches

“…By contrast, in all duck species examined here, the cortex produced interference effects as indicated by secondary reflectance peaks at shorter wavelengths (figure 2 and electronic supplementary material, S5). Further, we show that the cortex increases brightness and saturation-possibly owing to resonance occurring as a result of size matching between the thickness of the one-dimensional film (cortex) and lattice constant (melanosome spacing) of the two-dimensional PC [38]-and results in polarized iridescence ( figures 3 and 4). While the role of the keratin cortex in colour production has been studied in other iridescent bird species [11,12], to our knowledge, this is the first study to show the optical properties arising from both one-dimensional and twodimensional periodicity, rather than a one-dimensional multilayer.…”

One-dimensional metal–organic framework photonic crystals used as platforms for vapor sorption

“…20 Enhanced reflectivity is achieved by increasing the number of bilayers or by choosing dielectric materials featuring a high refractive index contrast (Scheme 1). 21 Currently, intensive research efforts are focused on the development of tunable optical sensors with a label-free operation and compact set-up. There are several approaches ranging from plasmonic noble metal nanotubes 22 or field effect transistors based on reduced graphene 23 to Bragg stacks built up from an alternating polymer architecture, 24 which deal with the implementation of these materials as tunable and label-free sensors.…”

Three-dimensionally ordered photonic crystal heterostructures with a double photonic stop band

“…In addition, the optical features presented here are better resolved compared to the optical properties of the PhC hetrostructures fabricated using other methods. 1,2,4,6,7 We show in this paper that the surface roughness of the initial PhC will play a major role in deciding the final optical quality of the PhC heterostructures. We have used colloidal spheres made of polystyrene ͑PS͒ and polymethyl methacrylate ͑PMMA͒ with different diameters in making the PhC heterostructure.…”

“…Photonic crystal ͑PhC͒ heterostructures have been fabricated in the past using convective self-assembling, [1][2][3] Langmuir-Blodgett ͑LB͒, 4,5 and controlled dip-coating 6 methods. Double photonic stop band is obtained in transmission/reflection for opal PhC partially filled with semiconductor materials.…”