Quantum Information studies the coding, transmission and processing of information taking into account the restrictions imposed by the laws of Quantum Mechanics. In this line of research, we study theoretical and experimental problems in Quantum Information and fundamental aspects of Quantum Mechanics in higher dimensions.
In recent years, we have designed and set up an experimental configuration capable of generating, manipulating and measuring larger quantum systems. For this we use single photons, that is, quanta of light, whose degree of freedom of transverse momentum is discretized by means of a sequence of spatial modulators of light. In this way, a high-dimensional quantum system is generated, which can be measured later. Our aim is to use this configuration to experimentally study (i) device-independent quantum protocols, (ii) efficient quantum-state tomography and (iii) the transmission of high-dimensional quantum systems.
Flexible, fast and secure free-space optical communication (FSO) links are becoming a necessity for high-speed data connections to backbone fiber optic links, as well as they are becoming the future of satellite networks and space communications. As the access of voice and data services into communication highways requires more bandwidth and flexibility, network providers require newer and more reliable technologies to provide last-mile access to end users. Free-space optical links use laser light to encode information by modifying and controlling one or more of its properties. Optical receivers are used for decoding such information with very low error probability. The combined use of quantum-level information technology with wireless free-space laser communication systems offers a truly secure exchange of sensitive information and may become a strong alternative for secure transactions between citizens and organizations.
In this research line, we explore new ways to improve optical communications through the study and manipulation of laser’s properties to carry digital information. Some of these include intensity, phase and polarization modulation; signal decoding techniques and algorithms; spatial and modal diversity (orbital angular momentum) for increased system capacity and strength; adaptive optics; and error-correction coding. We also study the behavior and the effects that the atmosphere produce on laser beams propagating over turbulent paths to design simplified channel models and evaluate new techniques for classical and quantum communications.
Performing secure communications through certain Quantum Key Distribution protocols requires the availability of quantum light sources that generate pairs of photons that exhibit entanglement. Currently, these sources are based on the propagation of a focused laser through a non-linear optical crystal, which converts a fraction of the laser power into entangled photons with some efficiency.
We study the design, synthesis and optical characterization of bulk metal-organic framework (MOF) crystals for second-order nonlinear optical applications, such as second harmonic generation (SHG) and spontaneous parametric conversion (SPDC). We develop large-scale computational tools to design and rank viable MOF candidates according to their linear and non-linear optical properties, develop crystal growth techniques to produce large single MOF crystals with tunable size, and implement sophisticated optical characterization techniques with both classical and quantum light.
The development of optics involves fundamental research on the interactions between light and matter and applied research in cutting-edge areas of future technologies, for example, photonics, optical and computer communication, storage and interconnections, biomedical and astronomical images. Recently, we have experimentally demonstrated programmable optical vortex arrays with arbitrary and controllable spatial configuration, where each vortex of matter acts as an orbital angular spin-moment photonic coupler. A few years ago, we have also demonstrated experimentally the existence of compact localized states in femtosecond written photonics lattices appearing due to a nontrivial flat band geometry.
We investigate the spatiotemporal dynamic that arises in extended systems when a high degree of interconnection between different parts of an optical wavefront and a given array is established. Our objectives are to increase the functionality and adjustability of photonic devices by increasing the coupling of light with the given written/induced structure.