CTF - Metamaterials. Unidad Asociada ICMM-CSIC/UPV

Home
nanocavity mirror image
Tuesday, 21 May 2013 14:45

Reflection in a mirror changes the handedness of the real world, and right-handed objects turn left-handed and vice versa (M. Gardner, The Ambidextrous Universe, Penguin Books, 1964). Also, we learn from electromagnetism textbooks that a flat metallic mirror transforms an electric charge into a virtual opposite charge. Consequently, the mirror image of a magnet is another parallel virtual magnet as the mirror image changes both the charge sign and the curl handedness. Here we report the dramatic modification in the optical response of a silicon nanocavity induced by the interaction with its image through a flat metallic mirror. The system of real and virtual dipoles can be interpreted as an effective magnetic dipole responsible for a strong enhancement of the cavity scattering cross section.
Read more...
 
silicon colloids metamaterials
Tuesday, 21 May 2013 14:44

It is generally accepted that the magnetic response of materials at optical frequency values is completely negligible. The recent discovery of Metamaterials (MMs) has broken this traditional understanding, since both the electric and the magnetic field are key ingredients in MMs. The top-down technology used so far employs noble metals with large intrinsic losses. Here we report on a bottom-up approach for processing MMs based on suspensions of monodisperse full dielectric silicon nanocavities with a large magnetic response in the near infrared region (NIR). Experimental results and theory show that silicon colloids (SCs) based liquid suspensions and photonic crystals made of two dimensional (2D) arrays of particles have strong magnetic response in the NIR region with small optical losses.
Read more...
 
Colloidal Crystal Thin Films
Tuesday, 21 May 2013 14:14

We show that hard spheres confined between two parallel hard plates pack denser with periodic adaptive prismatic structures which are composed of alternating prisms of spheres. The internal structure of the prisms adapts to the slit height which results in close packings for a range of plate separations, just above the distance where three intersecting square layers fit exactly between the plates. The adaptive prism phases are also observed in real-space experiments on confined sterically stabilized colloids and in Monte Carlo simulations at finite pressure..

Read more...
 
silicon nanocavities
Tuesday, 21 May 2013 11:07

The most popular photonic metamaterials are made of metals, which lead to inherent losses, particularly in the near infrared (NIR) and visible regions. One potential way to circumvent this obstacle concerns using high refractive index value dielectric structures. Here we report on the synthesis of silicon colloids by chemical vapor deposition (CVD) technique and their optical properties with show strong magnetic response in the NIR region. Both experimental results and theoretical calculations (Mie theory and the finite difference time domain (FDTD) simulations) clearly show that single submicrometer-sized silicon nanocavities support well defined and robust magnetic resonances, even in a liquid medium environment, at wavelength values up to six times larger than the cavity radius.
Read more...
 
Photonic Barcode
Thursday, 03 November 2011 11:08
A barcode is an optical readable representation of data, that consists of parallel lines of different widths separated by blank spaces, which contains encoded information about the object it attaches. In this paper we report on the use of high refractive index optical microcavities as photonic barcode structures. The encoding platform we show here consists of porous silicon microcavities. The intrinsic luminescence of porous silicon couples strongly to the whispering gallery modes of the microcavity resulting in a unique barcode like luminescent profile associated to each single particle. Since the photoluminescence emission of porous silicon microcavities appear in the transparent region of biological tissue it may have applications for sensing in biomedicine.
Read more...
 
<< Start < Prev 1 2 3 Next > End >>

Page 1 of 3