FGR MagSens

The exploitation of the quantum physical effect of entanglement has attracted great interest in various research areas in recent years. The fields of application include image generation and data encryption. The FOQUOS research group is working on the effect of ghost imaging as an imaging method. Using a non-linear crystal (e.g. beta-barium borate), entangled photon pairs consisting of signal and Idler photon can be generated from pump photons. Signal and Idler photon can be spatially separated and registered with different detectors. The wavelength range for the subsequent application is set by the pump photons and the non-linear crystal. A correlation measurement is used to evaluate the detector signals in order to create images of the object.

The goals of the research group consist of the realisation of suitable non-linear crystals for photon pair generation as well as the optimisation of the evaluation electronics for image generation. The wavelengths of the photons of the photon pair are adjusted by the non-linear crystal. Different materials as well as the influence of the geometric dimensions of the crystals are investigated by simulations. These results should enable the realisation of optics for the infrared range and, in the future, also for the UV range.

Fast and low-noise transmission is needed to optimise the evaluation electronics. Measurement times of several hours for a few images are state of the art so far. After adapting the signal processing, the aim is to shorten this measurement time. Furthermore, the synchronisation of several detectors is planned in order to further improve image generation.

General description of the Ghost Imaging procedure

The functioning of ghost imaging has been described and proven in various publications. However, a fundamental description including the assessment of various experimental parameters is still missing for this phenomenon. The creation of a theoretical model for the description of the effect as well as the determination of the resolving power of different application scenarios shall be realised by a basic description.

Simulation of nonlinear crystals

Different materials have an influence on the wavelength of the entangled photons. By simulation, the yield of these materials can be determined. Furthermore, the geometric dimension of the crystal influences the radiation characteristics of the photon pairs. With these estimations, the selection of suitable materials for the desired wavelength ranges in the IR and UV range is possible.

High-speed evaluation electronics

The goal is to quickly process the detector data to reconstruct images of the object under investigation. For this purpose, the carrier substrate must be as noise-free and low-loss as possible for high-frequency signals. The use of megapixel cameras for image acquisition is envisaged, where each pixel must be checked for correlation with the corresponding detector.

Demonstrators

The aim is to realise demonstrators for application scenarios in different wavelength ranges (IR, UV). Furthermore, a check of the resolving power in these scenarios is to be tested and compared with the simulation results. Further properties of the measurement system, such as the signal-to-noise ratio or the required measurement and evaluation times for image generation, are to be verified.