Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals

Lutetium aluminum garnet (LuAG) is the most promising candidate for a high-index lens material for use in microlithographic imaging lenses. In the deep ultraviolet spectral range the transmission of high-purity LuAG was measured using monochromatized synchrotron radiation. In the vicinity of the ban...

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Bibliographic Details
Main Authors: Liberman, Vladimir (Contributor), Letz, M. (Author), Gottwald, A. (Author), Richter, M. (Author), Parthier, L. (Author)
Other Authors: Lincoln Laboratory (Contributor)
Format: Article
Language:English
Published: American Physical Society, 2010-09-27T14:46:36Z.
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Online Access:Get fulltext
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100 1 0 |a Liberman, Vladimir  |e author 
100 1 0 |a Lincoln Laboratory  |e contributor 
100 1 0 |a Liberman, Vladimir  |e contributor 
100 1 0 |a Liberman, Vladimir  |e contributor 
700 1 0 |a Letz, M.  |e author 
700 1 0 |a Gottwald, A.  |e author 
700 1 0 |a Richter, M.  |e author 
700 1 0 |a Parthier, L.  |e author 
245 0 0 |a Temperature-dependent Urbach tail measurements of lutetium aluminum garnet single crystals 
260 |b American Physical Society,   |c 2010-09-27T14:46:36Z. 
856 |z Get fulltext  |u http://hdl.handle.net/1721.1/58712 
520 |a Lutetium aluminum garnet (LuAG) is the most promising candidate for a high-index lens material for use in microlithographic imaging lenses. In the deep ultraviolet spectral range the transmission of high-purity LuAG was measured using monochromatized synchrotron radiation. In the vicinity of the band gap below 7.8 eV, a scaling behavior of the absorption as a function of photon energy was observed. Temperature-dependent measurements allowed us to distinguish different absorption mechanisms which differ by their ability to couple to phonon excitations. Interpreting the Urbach tails measured at different temperatures, it was shown that the temperature independent tail is due to defects in the lattice, whereas the temperature-dependent part originates from the short term localization of exciton modes coupling to lattice distortions. These results allowed us to extrapolate the maximum transmittance which can be obtained with LuAG crystals at the lithographic wavelength of 193.39 nm. Accurate determination of the maximum transmission limit is critical in deciding whether the material can meet industry's specification for 193-nm-based high-index lithography. 
546 |a en_US 
655 7 |a Article 
773 |t Physical Review B