You can communicate with me in Czech, Dutch, English, French, German,
Polish, Russian, Slovak, and Ukrainian languages.
My free-time research interests
Various subjects of theoretical physics, including general scattering theory,
numerical solution of electromagnetic scattering problems,
negative refractive index metamaterials, luminescence and scattering properties
of small metal nanoparticles, affinity sensors,
subwavelength nanoguides, surface plasmons, optical imaging of biotissues,
quantum optics, light-matter interactions, theory of optical tweezers, and
physics of photonic band-gap structures, or, photonic crystals.
My work before 2001 has been summarized in the contribution Towards
complete photonic band gap structures below infrared wavelengths to the Proceedings
of the NATO ASI Photonic Crystals and
Light Localization in the 21st Century
(Kluwer, Amsterdam, 2001) and in the contribution K7.5,
Photonic
Crystals at Near-Infrared and Optical Wavelengths
[pdf], in the Proceedings of
the MRS Fall Meeting 2001 - BB symposium.
A popular review on the use, properties, and
fabrication of photonic crystals has recently appeared in
PhysicsWeb.
See also Guiding Surface Waves
and
Tungsten Crystals Could Provide More Power for Electrical Devices.
You will find more about why a periodic array of metal rods may be the best
way to create narrow, high-frequency microwave signals
for everything from satellites to cell phones
in Lattice Sends a Crystal
Clear Signal. Some additional information, together with selected photonic
web links, is supplied below:
J. J. Penninkhof, L. A. Sweatlock, A. Moroz, H. A. Atwater,
A. van Blaaderen, and A. Polman,
Optical cavity modes in gold shell colloids,
J. Appl. Phys. 103, 123105 (2008).
(Accompanying F77 code sphere.f. Read compilation and
further instructions here.)
A. van der Horst, P. D. J. van Oostrum, A. Moroz, A. van Blaaderen, and M. Dogterom,
High-refractive index particles
trapped in dynamic arrays of dual-beam optical tweezers, Appl. Opt. 47(17),
3196-3202 (2008).
(For accompanying F77 code opttrap.f read compilation and
further instructions here.)
J. J. Penninkhof, A. Moroz, A. Polman, and A. van Blaaderen,
Optical properties of spherical and oblate spheroidal gold shell colloids,
J. Phys. Chem. C 112, 4146-4150 (2008).
(Accompanying F77 code sphere.f. Read compilation and
further instructions here.)
Previous scientific highlights:
Together with Vassilis Yannopapas
we have recently published an article in
J. Phys.: Condens. Matter. 17, 3717-3734 (2005)
which shows that even a composite of inherently
non-magnetic homogeneous spheres can provide
a negative refractive index metamaterial.
Note that materials that exhibit magnetic response are:
i) particularly rare at THz and
infrared frequencies and, if they exist,
ii) they usually
suffer from high losses.
The resulting negative
refractive index structure is
a truly subwavelength structure with wavelength-to-structure ratio
as high as 14:1, which appears to be almost by 50% higher
than it has been achieved so far using split ring resonators and wires.
Our results were explained in the context of the extended
Maxwell - Garnett theory
(see accompanying F77 code EFFE2P) and reproduced by
the ab initio calculations
based on multiple-scattering theory. The role of absorption in
the constituent materials is discussed.
The centre wavelength lambda of the negative refractive
index band can be tuned over a wide frequency
range from deep infrared to terahertz (1-10 THz) frequency ranges.
This can
lead to efficient optical components for terahertz beams, which
are required in many scientific and technological applications,
ranging from the imaging of biological materials to manipulating
quantum states in semiconductors, from drug discovery and medical
imaging to security screening.
Power (total and differential) of a dipole radiating anywhere inside or
outside a multilayered sphere has been determined.
Dipole can be located either outside or embedded anywhere within
the multilayered sphere. Among many other quantities, Green's function
at coinciding spatial arguments,
radiative decay rates, the Ohmic loss contribution to the non-radiative decay rates,
and level shifts have been determined.
A cumbersome algorithm of H. Chew, P. J. McNulty, and M. Kerker,
Raman and fluorescent scattering by molecules embedded
in concentric spheres, J. Opt. Soc. Am. 66, 440-444 (1976) is avoided and
a new transfer matrix alternative has been provided. The results presented in
Annals
of Physics (NY) 315, 352-418 (2005) (published online on 7 October 2004, although
it was not straightforward to publish it; see
story behind this article), where it has
since belonged for over one year to the
top 5 most downloaded articles,
may find various applications for inelastic light-scattering (fluorescence or Raman)
spectroscopy for characterizing single micrometer or nanometer sized particles, nano-plasmonics,
surface enhanced Raman scattering (SERS),
in LIDAR applications for remote sensing of both molecular
and particulate constituents of atmosphere, engineering of the
radiative decay for biophysical and biomedical applications, imaging of buried
saturated fluorescent molecules and imaging of surfaces in near-field
optical microscopy, in the study of the effects of light absorption
and amplification on the stimulated transition rates of the electric-dipole
emission of atoms or molecules embedded in micro- or nano-structured spheres,
stimulated Raman scattering, the interplay
between lasing and stimulated Raman scattering, etc.
Here you can download a limited Windows executable
chew (download also material data
file Audat.dat), which calculates
the electric dipole radiated power loss together with the dipole power
loss due to Ohmic losses for a coated SiO2@X@SiO2 sphere in water. Refractive index
of SiO2 is taken to be 1.45, that of water 1.33, and that of X (e.g., gold, silver, etc.) you
can supply yourself. The sphere options are identical
to that in scattering from a
multilayered sphere. You can download full code here.
My second article
``Spectroscopic properties of a two-level atom
interacting with a complex spherical nanoshell",
Chem. Phys. 117(1), 1-15 (2005)
(published online on 9 August 2005) [preprint
available as
quant-ph/0412094],
deals with an application of the theory presented in
Annals
of Physics (NY) 315, 352-418 (2005) to nano-matryoshka plasmonic spherical
structures of Prodan et al. [see Science 302, 419 (2003)].
You can download here accompanying source F77 code CHEWFS
and reproduce all the figures in my article. Windows executable is
available as an on-line Appendix A of my article.
Any dielectric material can be used to fabricate a photonic
crystal with a sizeable and robust complete photonic bandgap (CPBG) in three dimensions,
as long as small metal inclusions can be added.
These finding (i) open the door for any semiconductor
and polymer material to be used as a genuine
building block for the creation of photonic crystals with a CPBG
and (ii) significantly increase the possibilities
for experimentalists to realize a sizeable and robust CPBG at
near-infrared and in the visible. See my contribution K7.5,
Photonic
Crystals at Near-Infrared and Optical Wavelengths
[pdf],
in the Proceedings of
the MRS Fall Meeting 2001 - BB symposium. A more complete version
can be found in my article
Metallo-dielectric diamond and zinc-blende photonic structures,
Phys. Rev. B 66, 115109 (2002)
[cond-mat/0209188]
[pdf].
In a recent development, purely dielectric diamond structures have been
fabricated by F. Garcia-Santamaria et al, Nanorobotic Manipulation of
Microspheres for On-Chip Diamond Architectures, Adv. Matter. 14, 1444-1147 (2002).
Exponentially convergent lattice sums of the two-dimensional (2D)
free-space periodic (in one dimension) Green function were calculated.
These results are discussed
in my Opt.
Lett. 26, 1119-1121 (2001)
[pdf].
Full calculational details, together with the case of a 1D lattice
in 3D, have been presented in a follow-up
Quasi-periodic Green's functions of the Helmholtz and Laplace equations,
J. Phys. A: Math. Gen.
39, 11247-11282 (2006)
[erratum]
[math-ph/0602021].
The accompanying numerical code OLA is available
here and some additional information
on that story is supplied here.
For a diamond lattice of dielectric spheres,
the bulk photonic KKR method yielded quantitatively different results
from earlier plane-wave calculations.
See Metallo-dielectric diamond and zinc-blende photonic
structures,
Phys. Rev. B 66, 115109 (2002)
[cond-mat/0209188]
[pdf],
together with my comment and read an additional
information on that story supplied
here.
An fcc arrangement of metal spheres can open a full
photonic band gap in the visible. Read more in
``Three-dimensional complete photonic bandgap structures
in the visible,"
Phys. Rev. Lett. 83, 5274-5277 (1999).
A critical dielectric contrast for opening a complete photonic band gap
in an inverted opal structure has been independently determined by the bulk
photonic KKR method. Read more in ``Photonic band gaps of
three-dimensional face-centered cubic lattices,"J.
Phys.: Condens. Matter 11, 997-1008 (1999).
Some peculiar features have been established in a spin-dependent
Aharonov-Bohm scattering. Read more in
``The single-particle density of states,
phase-shift flip, bound states, and a resonance in the presence
of an Aharonov-Bohm potential,"Phys. Rev. A 53, 669-694 (1996).
