Department of Physics, University
of Utah
In the absence of light localization a new problem arises:
trapping of
light for a long time. The importance of such traps is determined by
their role as high-Q resonators for coherent lasing.
In the first part of the talk I will discuss the problem of trapping of
a
photon in disordered media. The experimental manifestation of such
trapping is coherent random lasing, the effect, which has been
discovered
just a few years ago. I will review the experimental results and
present
the theory of high-Q random resonators, which are responsible for a
trapping of photon in disordered media and serve as the resonators for
coherent random lasing.
In the second part of the talk I will discuss the problem of trapping
of
light in periodic structures-photonic crystals. The conventional
approach
to this problem is introduction of a defect inside a photonic crystal
with high contrast of dielectric constant, i,e. inside a photonic
crystal
with complete bandgap. Such a defect creates an in-gap localized mode.
I
will show that strong localization of light can be achieved in photonic
crystals without complete bandgap by introducing a special type of
defects into “magic” photonic crystal with special geometry of unit
cell.