No abstract

We present a THz investigation of histo-pathological samples including the larynx of a pig and a human liver with metastasis. Our measurements show that different types of tissue can be clearly distinguished in THz transmission images, either within a single image or by a comparison of images obtained for different frequency windows. This leads to the problem that images obtained for different frequencies inherently have a different spatial resolution. An image obtained from two such images by a simple mathematical operation may contain artefacts. We discuss measures to deal with this problem. Furthermore, we investigate the possibility of improving the spatial resolution of THz images. Finally, we present a cw THz imaging system based on a photomixer and an external cavity semiconductor laser that allows for simultaneous two-mode operation. The cw system is less expensive and more compact than conventional time-domain imaging systems.

No abstract

No abstract

1 o confidence level. below 2.7-10*4 by the present experiment. These limits are given at a dilatation factor. The fourth order limit of this deviation is set sets a second order limit of 1.1·10'6 for any deviation from the time of v = 6.4% c. A precision of AV/V < 9.1O·9 has been obtained, which as a test of the time dilatation factor Y = (1-{32)*1/2 at an ion velocity 7Li+ the Doppler shift has been measured by saturation spectroscopy theory of relativity. With an optical A type three level system of allows for precision experiments testing the limits of the special Laser spectroscopy at the heavy ion storage ring TSR in Heidelberg ABSTRACT GSI, Darmstadt

We present a first investigation of liquid crystals in the frequency range around 1 THz using THz time-domain spectroscopy. As a model system we use 4-(trans-4'-pentylcyclohexyl)-benzonitril (PCH-5). The THz refractive indices for the nematic state are comparable to that for visible frequencies. Yet, the THz birefringence of PCH-5 is smaller than its optical birefringence. Furthermore we find that PCH-5 has a rather small absorption.

No abstract

No abstract