Project C10 - High-power Tunable THz Source 

Principal Investigator: Prof. Dr. Clara Saraceno

Most sources of coherent radiation in the 250 GHz – 5 THz range targeted within MARIE are limited in power to << μW power levels. However, it remains unclear whether higher power levels are not required for the challenging new measurement techniques to be demonstrated in this ambitious project. For example, one of the principal challenges of MARIE is to demonstrate techniques for material-resolved sensing and imaging at large distances and of large areas in reflection. The requirement in terms of source power to achieve these goals, remain however unclear. In most cases sufficient power is not available for testing devices and measurement techniques, thus strongly limiting the explored parameter space. Different measurement techniques and detectors for ellipsometry and reflectometry exhibit complex signal-to-noise ratio figures: determining the requirements in terms of power from the source side is a crucial task, not only to evaluate the limits of the proposed techniques, but also to define what the future goals in terms of source performance this project will encompass.

In C10, we suggest to solve this challenge by demonstrating a tunable, table-top source of high-power, narrowband THz pulses radiation covering the whole 0.25 – 5 THz region of the electromagnetic spectrum, which is the region of interest of MARIE. This source would achieve power levels orders of magnitude above what is currently commercially available (in the hundreds of milliwatts range), reaching comparable levels to what can be achieved with free electron lasers. Our system is planned to operate in a laboratory environment and be sufficiently compact to be transportable to other laboratories for various tests. In addition to providing a unique benchmark testing unit for the targeted measurement techniques within MARIE, it will provide additional data to validate propagation models in this frequency range.

This project will provide a missing brick in MARIE´s vision by strengthening the available testing capabilities in the first stage of the project. Both devices and measurement methods will immensely benefit from the availability of the targeted high power THz source. The exploration of a wider parameter space will also benefit simulation tools developed by different projects in MARIE, providing additional means for confirming the corresponding algorithms. In this way, it will allow to better define the goals for the second and third phases of the project not only in terms of measurement methods (M projects) and requirements on the sources (C projects) but also by extending the testing capabilities to frequencies >1 THz.