Measurement depth enhancement in terahertz imaging of biological tissues

Viscoelasticity imaging of biological tissues with phase-resolved photoacoustic measurement.

A method for noninvasive viscoelasticity imaging of biological tissues using phase-resolved photoacoustic measurement is presented. We deduced the process of photoacoustic effect on the basis of thermal viscoelasticity theory, and established the relationship between the photoacoustic phase delay and the viscosity-elasticity ratio for soft solids. Agar phantoms with different densities and diff...

Microwave Imaging of Biological Tissues

Time-domain transillumination of biological tissues with terahertz pulses.

We present time-domain transmission imaging of an opaque structure in pork-fat tissue obtained with a terahertz (THz) field sampling technique. Compared with imaging with near-infrared pulses, the terahertz sampling technique shows significantly enhanced contrast, as a result of low scattering. For enhanced spatial resolution, we show mid-infrared THz imaging of onion cells. Water absorption of...

Enhanced depth resolution in terahertz imaging using phase-shift interferometry

We describe an imaging technique for few-cycle optical pulses. An object to be imaged is placed at the focus of a lens in one arm of a Michaelson interferometer. This introduces a phase shift of approximately p between the two arms of the interferometer, via the Gouy phase shift. The resulting destructive interference provides a nearly background-free measurement, and a dramatic enhancement in ...

Terahertz pulsed imaging of freshly excised human colonic tissues.

We present the results from a feasibility study which measures properties in the terahertz frequency range of excised cancerous, dysplastic and healthy colonic tissues from 30 patients. We compare their absorption and refractive index spectra to identify trends which may enable different tissue types to be distinguished. In addition, we present statistical models based on variations between up ...