Abstract

Compressive sensing imaging techniques are proving useful in many applications, maybe more so than any other application THz imaging could have the most to gain since array imaging techniques are still not widespread. By discretizing the object using manually controllable pixels either near the object or on the image plane this method has been shown to effectively generate images of objects using single pixel THz detectors [1]. Here we demonstrate this with a unique graphene based optoelectronic device which allows us to modulate the THz field through an array of columns or rows distributed throughout its face. The device uses a layered structure whereby the transmission of the THz-field is attenuated due to the large charge accumulation under applied differential bias between two sheets of graphene separated by an ionic conducting dielectric medium. Different regions of the device are isolated in sections of columns or rows which can be biased individually. The large charge build-up in each column or row can reduce the transmission by more than 50% which is sufficient to apply CS reconstruction techniques [2]. The set-up shown in Fig. 1 is used to demonstrate that a highly reflective, metal negative surface can be imaged. To reconstruct the image Total Variation (TV) minimization algorithm is used [3]. To assess the performance of the algorithm the reconstructed image was compared to the simulation of the ideal target. The comparison was done using the 𝜒² image quality assessment (IQA) index.

© 2015 IEEE