The penetration depth of an evanescent wave in Attenuated Total Reflection (ATR) is dependent on the wavelength of the radiation utilised. At THz frequencies, the penetration depth into biological tissues is in the order of 0.1 to 0.5 mm; rendered pig lard was used as a model sample in this study. A method for the direct measurement of the evanescent wave penetration depth is presented which allows for the estimation of the dispersion of the complex refractive index by using the reflection of the evanescent wave from varying sample depths. The method employs frustrated total internal reflection, and has been demonstrated by using the THz/Far-IR beamline at the Australian synchrotron, and modelled using finite difference time domain (FDTD) simulations.
A top reflecting mirror was added to the attenuated total reflection (ATR) method to measure absorption of bio-materials at sub-mm wavelengths (THz) wavelengths.
物質理工学院 Saulius Juodkazis特任教授の共著論文
“Characterisation of Biological Materials at THz Frequencies by Attenuated Total Reflection: Lard”
が、 Appl. Sci. に掲載されました。（DOI:10.3390/app10238692）