Simultaneous measurement of orthogonal terahertz fields via an emission multiplexing scheme.

We propose a polarization sensitive terahertz time-domain spectrometer that can record orthogonally polarized terahertz fields simultaneously, using fibre-coupled photoconductive antennas and a scheme that modulated the emitter's polarization. The s and p channels of the multi-pixel terahertz emitter were modulated at different frequencies, thereby allowing orthogonal waveforms to be demultiplexed from the recorded signal in post-processing. The performance of the multi-pixel emitter used in this multiplexing scheme was comparable to that of a commercial single-polarization H-dipole antenna.

THz measurements: the effects of pressure on skin reflectivity.

Terahertz (THz) light is non-ionizing and highly sensitive to subtle changes in water concentration which can be indicative of disease. The short THz penetration depth in bio-samples restricts measurements to be in a reflection geometry and the sample is often placed onto an imaging window. Upon contacting the imaging window, occlusion and compression of the skin affect the THz response.

Three-dimensional imaging of optically opaque materials using nonionizing terahertz radiation.

Terahertz electromagnetic radiation has already been shown to have a wide number of uses. We consider specific applications of terahertz time-domain imaging that are inherently three-dimensional. This paper highlights the ability of terahertz radiation to reveal subsurface information as we exploit the fact that the radiation can penetrate optically opaque materials such as clothing, cardboard, plastics, and to some extent biological tissue.

Relations between the timing of the second heart sound and aortic blood pressure.

The second heart sound (S2) is triggered by an aortic valve closure as a result of the ventricular-arterial interaction of the cardiovascular system. The objective of this paper is to investigate the timing of S2 in response to the changes in hemodynamic parameters and its relation to aortic blood pressure (BP). An improved model of the left ventricular-arterial interaction was proposed based on the combination of the newly established pressure source model of the ventricle and the nonlinear pressure-dependent compliance model of the arterial system.