The transformation of teracycle radiation Annotation Experiments

The transformation of teracycle radiation

Annotation Experiments on registration of teracycle waves were done with the help of special plant. Images are obtained from the infrared camera and contain converted terahertz signal. The techniques of working with an infrared camera, an aspherical lens and a source of terahertz radiation are mastered.

Introduction For visualization of terahertz radiation is created the plant that use the conversion terahertz radiation to the infrared range with the next registration of the infrared camera. Terahertz radiation is harmless to humans in comparison with X-ray one. Therefore, it is suitable for using in the inspection system. The second application is to study the internal structure of the material, since THz radiation has good permeability. The third is the visualization of beams in free-electron lasers and measuring their power. The most interesting are imaging systems that work in real time, i. e. allowing to provide the picture frame rate of 10 Hz and above. The aim of the work is to visualize a beam of terahertz radiation.

The theoretical part. To calculate the dependence of the characteristics of the converter on the thickness of the dielectric layer KTIPM employers took the radially symmetric model. Converter was taken as a circular membrane and stored under vacuum. Its diameter is 50 mm, the basis of the converter is a dielectric layer (in this case it is a polypropylene film).

The description of the plant. The source generates a monochromatic beam with a frequency of 140 GHz. A lens is required for focusing and collimating the beam to the surface of the converter. Obtained from the source of terahertz beam is absorbed by the converter. This is due to the topological structure on its surface. The absorbed energy is re-emitted by the other side of the converter, which is coated with a coefficient of grayness, close to 1. The aperture of the converter is 50 mm, the thickness of the gray layer - 15 mm, the meta-layer made of graphite has a thickness of 40 mm. The obtained distribution of the heat radiation is detected by a thermal camera connected to the PC.

The experimental procedure. First we create the plant (its block-scheme and photo are shown on previous slides), then the plant is powered on. THz radiation source, a lens converter, and an infrared camera must be on the same optical axis. We should make the first dark frame, which will then be subtracted from all the next images. A computer program helps us to get a signal. We have recorded videos of the beam during the opening and closing of the source of terahertz radiation with a metallic shutter (see the next slide).

The discussion of the results. The data indicates that the converter is able to convert infrared to terahertz radiation. Its speed was small, about 10 frames per second.

Conclusions. With the proposed converter of terahertz radiation terahertz beam of electromagnetic radiation can be visualized to the infrared spectrum. The quality of the image, its contrast and resolution are suitable in the future for practical use (after improving the design of the converter, mostly - by reducing its thickness).

That’s all!