Phase shift ring down measurement approach (PS-CRDS) is used to develop a real time biosensor which can
simultaneously track the quality factor Q and the resonant wavelength λr of microcavities as a function of the
biodetection event. We have developed a mathematical model to predict the binding event with high accuracy
by utilizing the information from these two physical parameters (Q and λr). Experiments are also conducted to
validate the model. Hence, PS-CRDS biosensor in conjunction with the estimation model, will pave the way for
highly sensitive measurements of biological entities/processes ranging from micron to nano scale.
The dielectric properties of common household powders from 0.6 to 1.2 THz are presented in this paper. Terahertz
Dispersive Fourier Transform Spectroscopy was used to yield the dielectric properties of powders as a continuous
function of frequency. Tests were conducted using a polarized interferometer and two cryogenically-cooled high
frequency detectors. Dielectric spectroscopy was utilized to provide high-resolution and precise information on the
dielectric spectra of powders including the powder's unique resonance signature. This signature can be employed to
detect the presence of a hoax or harmful powder within a baggage or mail package.