|Terahertz Biospectroscopy, Modeling and Imaging |
Chemistry and Chemical Biology
|Edwin J. Heilweil, National Institute of Standards and Technology.|
11:00 AM, WL-Aud
Terahertz (THz) absorption spectra for solid-phase biotin, amino acids, short peptides, sugars and related biomaterials at 77 and 295 K will first be presented after a brief methodology overview. A high degree of spectral and structural information exists for these biosystems in the 0.5-20 THz (15 to 666 cm-1) range. The spectral density and uniqueness of distinct features for each system suggests that crystalline, enantiomeric and sequence-dependent structural information can be extracted from THz spectra using quantum mechanical solid-state modeling. Gas phase and solid-state ab initio density functional theory is used to calculate low frequency modes and obtain model THz infrared absorption spectra of samples including glycine, cysteine, serine, glucose, galactose and lactose. Our latest calculations will be compared to experimental spectral results.
THz imaging may eventually be a method of choice for materials research and medical diagnostics. We are attempting to advance two-dimensional hyper-spectral methods for imaging large area samples (e.g., semiconductor wafers) to rapidly assess impurity inhomogeneities, imperfections and for homeland security applications. Examples of sample-scanning and CCD up-conversion methods will be presented and new optical approaches and requirements for wide-area long-distance detection discussed.