Abstract: Imaging techniques of pharmaceutical preparations such as tablets are disclosed. The techniques combine the measurement of reflected/transmitted terahertz radiation originating from within the tablet and data analysis localized in frequency and time in order to enable a three dimensional image indicating composition to be obtained.

Abstract: A probe array (1) for an imaging system for examining an object (19) comprising at least one emitter (7) for emitting radiation, a plurality of detectors (9) for detecting radiation and means for directing radiation emitted by the at least one emitter (7) to the object (19) and for directing radiation reflected from the object (19) to at least two of the plurality of detectors (9) wherein in use the emitted radiation is scanned by means (21) across the object (19).

Abstract: Method and apparatus for investigating a sample particularly a pharmaceutical tablet. An emitter and/or the sample are initially positioned so that the emitter is at a predetermined distance and normal angle to a first point on a surface of the sample. The emitter then irradiates the sample with radiation having a plurality of frequencies in the range from 25 GHz to 100 THz at a plurality of points on the surface of the sample. Relative motion is possible between the emitter and the sample so that the surface of the sample can be tracked to maintain the predetermined distance and normal angle at each of the plurality of points, and allow radiation transmitted and/or reflected from the sample at the plurality of points to be detected. This has particular application to imaging the structure or composition of a coating on a pharmaceutical tablet.

Abstract: Apparatus and method for detecting an explosive material, involving irradiating an object with a continuous wave (CW) or pulsed beam of Terahertz radiation, preferably in the frequency range of 100 GHz to 100 THz and detecting radiation transmitted and/or reflected from the object. A spectrum is constructed from the detected radiation, which is indicative of a fundamental property of the explosive material. This constructed spectrum is compared with one or more known spectra of explosive materials to determine whether a likeness exists.

Abstract: Method and apparatus for irradiating a sample with Terhertz radiation and detecting non-specular radiation in order to characterise the internal structure of the sample. Terahertz radiation specularly reflected from the surface is minimised so that it does not mask the weaker signal originating from the internal structure of the sample.

Abstract: An emitter for emitting radiation in a first range of frequencies comprising: a photoconductive material (11); and first and second contact elements (12, 13, 14) separated by a photoconducting gap provided by said photoconducting material (11), for applying a bias across said photoconducting gap, wherein at least one of said first and second contact elements (12, 13, 14) comprises a resistive element (14) for restricting current flow between said first and second contact elements in a second range of frequencies lower than the first range of frequencies.