Abstract

There is universal interest in pursuing the development of Quantum Technologies. They promise to transform information technologies beyond our capabilities using classical resources, for example with enhanced precision in measurement, secure communications and high speed computation. Quantum states of light are ideal candidates as the information carriers for these technologies. The ability to create, coherently manipulate, and detect these states of light also underpins both classical and quantum knowledge and its application. Specifically, encoding and transferring information in the time-frequency domain is a natural extension to current classical communications. It allows large dimensional encoding and high fidelity transfer over existing optical networks. Furthermore, the ability to completely characterize the time-frequency state of light at the single-photon level will have direct impact in fields where low-light sensing is necessary. Here we present a toolbox of resource efficient methods to characterize single photons by investigating their purity and fidelity. The complete state is yet to be measured in the time-frequency domain, thus we also introduce a novel full state tomography technique using electro-optical shearing interferometry.