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Awards
Karl-Franzens-University Graduate Research Award for "Outstanding Scientific Achievement", 2002.
Max-Kade Foundation Postdoctoral Fellowship (nominated by the Austrian Academy of Sciences), 2002-2004.
Research Interests
The overall research theme of the Bartl Group is in the areas of Micro- and Nanophotonics - novel optical concepts that allow one to actively control and manipulate photons in revolutionary new ways. Such concepts are considered key components in future devices, such as all-optical integrated circuits and photonic chips. In particular, my group is interested in emerging photonic concepts such as photonic crystals, optical microcavities, single-photon sources, and bio-photonics. We employ state-of-the-art micro-spectroscopy techniques (sub-micron spatial and picosecond time-resolution) as well as optical and electron microscopy imaging to systematically study non-classical optical phenomena and manipulation of photons in specifically engineered electromagnetic environments.
Scanning electron micrographs of self-assembled 3-dimensional photonic air-sphere crystals in titania. Scale bar is 300 nm.
Photonic Band Structure Crystals
Photonic band gap structures (photonic crystals)
are artificial electromagnetic crystals (with "lattice constants"
on the order of the wavelength of light) for which the band structure
concepts of solid-state physics are applied to electromagnetism. This
leads to fundamentally new optical principles such as localization of
light in bulk materials and control of spontaneous emission over a broad
frequency range. Research in my group is devoted to translating many of
these new theoretical concepts into real 3-dimensional material systems
(utilizing colloidal, (bio)-directed and molecular assembly techniques)
and to investigate the effects of these non-classical optical
principles on spontaneous emission, amplification of light (lasing), energy
transfer rates, etc. By conducting such detailed spectroscopic studies
on optically activated photonic crystals, we seek to gain new insights
into fundamental quantum optics processes.
Magneto-Optical Phenomena
The combination of magnetism and photonic band structure concepts is of great interest both for fundamental studies of magneto-optical phenomena and for applications as optical isolators and spatial light modulators. Our research focuses on 1) fabricating nano- and micro-structured magnetic composites exhibiting distinct photonic band
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structures and 2) studying
the effect of photonic band structure phenomena such as localization of
light and enhancement of density of optical states at a photonic band
edge on basic magnetic and magneto-optical properties (Faraday rotation,
Kerr effect, magnetization-induced 2nd harmonic generation, etc.).
Density of optical states (DOS) in photonic crystals with a stop gap (left) and a full band gap (right) compared to free space.
Single-Chromophore Spectroscopy
The generation, detection, and control over single-photon sources lie at the heart of quantum optics and information processing. Research in my group is focused on exploring new single-photon sources and studying their optical properties (emission properties, photon dynamics and statistics). In particular, we are interested in the spectroscopy of single ions (transition metal and rare earth ions) in the form of organo-metallic complexes or doped into solid-state matrices. Ion-based single-photon sources are not only an attractive alternative to e.g. single-molecule or nanocrystal-based sources, but they should also provide valuable basic insights into fundamental crystal field and group theoretical concepts at the single-ion level.
Selected Publications
- M. H. Bartl, S. W. Boettcher, K. L. Frindell, G. D. Stucky " 3-D Molecular Assembly of Function in T itania-Based Composite Material Systems" Acc. Chem. Res. 2005 , 38 , 263-71 .
- M. H. Bartl, S. W. Boettcher, E. L. Hu, G. D. Stucky "Dye-Activated Hybrid Organic/Inorganic Mesostructured T itania Waveguides" J. Am. Chem. Soc. 2004 , 126 , 10826-27.
- M. H. Bartl, S. P. Puls, J. T ang, H. C. Lichtenegger, G. D. Stucky "Cubic Mesoporous Frameworks with a Mixed Semiconductor Nanocrystalline Wall Structure and Enhanced Sensitivity to Visible Light" Angew. Chem. Int. Ed. 2004 , 43 , 3037-40.
- M. H. Bartl, B. J. Scott, G. Wirnsberger, A. Popitsch, G. D. Stucky "Single-Photon Hot Band Absorption Induced anti-Stokes Luminescence of Rhodamine 101 in Mesostructured T hin Films" ChemPhysChem 2003 , 4 , 392-95.
- J. N. Cha, M. H. Bartl, M. S. Wong, A. Popitsch, T . J. Deming, G. D. Stucky "Microcavity Lasing from Block Peptide Hierarchically Assembled Quantum Dot Resonators" Nano Lett. 2003 , 3 , 907-11.
- M. H. Bartl, E. C. Fuchs, K. Gatterer, H. P.
Fritzer, M. Bettinelli, A. Speghini "Spectroscopic and Crystal
Field Investigation of Kramers Ions: Nd 3+ :YAB - a Case Study of the
Crystal Field Structure of the 4 I 9/2 Ground State" J. Solid
State Chem. 2002 , 167 , 386-92.
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