Photonic Crystals and their applications to microwave and photonic devices
Speaker: Dr Marian Majewski, ITEE
When: 2003-07-29 14:00:00
Venue: 78-622
Host: Dr Marian Majewski
Abstract:Photonic Crystals (PCs) are periodic structures and there are
natural examples already existing in nature which reflect
electromagnetic radiation as propagation through them is selectively
prohibited. Semiprecious opals and wings of some tropical
butterflies known for their brilliantly rich colours are just only
two examples of natural photonic crystals. Present work on
artificial PCs concentrates on copying these unique properties found
in nature to use them to develop novel photonic and microwave
devices.
The action of repulsion/reflection of electromagnetic waves,
whatever the frequency at which it occurs is due to the fabric of
the crystal. The periodicity and the fill factor of the crystal are
important characteristics to the formation of the desired bad gap.
In principle, the PC operation relies on producing the optical
equivalent of the 'forbidden energy band-gap' to the well known
electronic bad-gap in the electronic structure of semiconductor
crystals. The electronic band-gap excludes electrons of certain
energies - an essential feature of many semiconductor devices
ranging from transistors to lasers. This property of PCs enables one
to fully control light (electromagnetic waves) propagation in any
direction and at the desired wavelength range. The light in PCs
travels in a form of Bloch waves that are similar to ordinary plane
waves in continuous crystals, and because of the scalability of this
property of PCs they can also be used at microwave/millimetre wave
frequencies for integrated circuits and antennas, for example.
First artificial PCs (or Photonic Band-Gap (PBG) materials) were
proposed about a decade ago by Sajeev John (Univ. of Toronto), and
Eli Yablonovitch (UCLA).
The seminar will start with a brief outline of some important
similarities between the quantum mechanical (periodic potential) and
electromagnetic (periodic dielectric) analytical treatment of the
solid-state matter. Then the three basic PC structures namely; 1-D,
2-D, and 3-D and their fundamental properties will be
discussed. Subsequently, several practical microwave (planar
antenna), and photonic devices (waveguides, couplers, single-mode
laser, and a super-prism) using PCs will be presented. In this part
a brief discussion on the recent commercial availability of the PC
based optical fibres will be included.
In addition, some basic characterization methods that are applicable
to PC devices at both microwave and optical frequencies will be
presented.
Finally, comments on the leading research group in this area
worldwide will conclude the seminar.
Biography:Speaker biography see http://www.itee.uq.edu.au/~mpsg/
Type: ITEE Seminar
Contact:Dr Marian Majewski, seminar host (mjm@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator)
(guido@itee.uq.edu.au)