PHYSICAL & MATERIALS CHEMISTRY
Research Associate Professor
Diploma, Graz University of Techn., Austria, 2000
Dr. rer. nat. (Ph.D.), Karl-Franzens-University, Austria 2002
Max-Kade Postdoctoral Fellow, University of California, Santa Barbara, 2002-2004
Postdoctoral Associate, California NanoSystems Institute (UCSB), 2004-2005
Activities & 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.
- DuPont Young Professor Grant Award, 2007
- Scialog Fellow, Research Corporation for Science Advancement, 2013
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.
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 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.
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.
Natural Photonic Architectures
Photonic structure engineering is a widely used method in nature to produce intense iridescence colors. Many species of butterflies and beetles in particular have developed a wealth of cuticular exoskeleton photonic crystal structures, resulting in a variety of optical effects throughout the visible range of the electromagnetic spectrum. Research in my group is focused on identifying interesting natural photonic crystals, explore their 3-dimensional structures, and study their structure-photonic property relation. From studies of these natural photonic structures we strive to develop new synthetic architectures with optimized photonic properties.
Cuticular exoskeleton photonic crystal structure of the weevil Lamprocyphus augustus.
- J. T. Siy, E. M. Brauser, M. H. Bartl, "Low-Temperature Synthesis of Colloidal CdSe Nanocrystal Quantum Dots" Chem. Commun. 2010, DOI:10.1039/C0CC02304C.
- J. W. Galusha, M. R. Jorgensen, M. H. Bartl, "Diamond-Structured Titania Photonic Band Gap Crystals from Biological Templates" Adv. Mater. 2010, 22, 107.
- J. W. Galusha, L. R. Richey, M. R. Jorgensen, J. S. Gardner, M. H. Bartl, "Study of Natural Photonic Crystals in Beetle Scales and Their Conversion into Inorganic Structures via a Sol-Gel Bio-Templating Route" J. Mater. Chem. 2010, 20, 1277.
- D. Chaudhuri, J. W. Galusha, M. J. Walter, N. J. Borris, M. H. Bartl, J. M. Lupton, "Towards Sub-Diffraction Transmission Microscopy of Diffuse Materials by Using Silver Nanoparticle White-Light Beacons" Nano Lett. 2009, 9, 952.
- J. W. Galusha, L. R. Richey, J. S. Gardner, J. N. Cha, M. H. Bartl, "Discovery of a Diamond-Based Photonic Crystal Structure in Beetle Scales" Phys. Rev. E 2008, 77, 050904.
- J. W. Galusha, C.-K. Tsung, G. D. Stucky, M. H. Bartl, "Optimizing Sol-Gel Infiltration and Processing Methods for the High-Quality Planar Titania Inverse Opals" Chem. Mater. 2008, 20, 4925.
- J. W. Galusha, K. Carter, M. H. Bartl "3-D Photonic Band Structure Engineering in Self-Assembled Photonic Crystals" Mater. Res. Soc. Symp. Proc. 2006, 0988-QQ05-08.