Monthly Archives: February 2011

Bragg layer, 1D optical crystal fibre

Historically the 1D photonic crystal has been known as the Bragg reflector or mirror, a periodic structure composed of two alternating layers of thickness t=\lambda/4n, where n is the refractive index of the layer and lambda is the free space wavelength for which optimal reflection has been designed.[Y. Yi, http://photonics.mit.edu/Photonic_Crystals.html%5D

A popular example of a photonic crystal device is the photonic crystal fiber, successfully demonstrated by Fink, Joannopoulos et al. at MIT. The ‘Omni guide’ fibre were fabricated using a bilayer (polymer and AsSe glass).[Nature 420, 650-653 (12 December 2002)]

The first demonstration of a photonic crystal waveguide, a planar-processed version of this device, developed by the EMAT group (see in figure). Comprised of a conformal cladded 1D Si/Si3N4photonic crystal; the waveguide core is a defect layer of SiO2.[Y.Yi]

Also, other groups (http://www.4spepro.org/view.php?article=002597-2010-02-05) demonstrated the fabrication of Bragg layer waveguide in polymer.

The future challenge will be demonstration of Bragg-layer fibres in all-glasses.

 

 

Antennas for light

Optical antennas devices can convert freely propagating optical radiation into localized energy (vice versa). They enable the control and manipulation of optical fields at the nanometre scale, and hold promise for enhancing the performance and efficiency of photodetection, light emission and sensing. [Lukas Novotny, NATURE PHOTONICS | REVIEW]

 

Applications:

Photodetection and photovoltaics

Antenna probes for nano-imaging

Nonlinear signal conversion

Information processing

Super-bright single-photon sources

[http://www.nature.com]

Periodic table & optics

Discover relationship between Periodic table & optics