Final Report Summary - SLICA (Stationary Light In Cold Atoms)
Our modern knowledge-based society relies on fast and efficient processing of information. Conventional electronic data storage and processing are already about to reach their limits in terms of capacities and processor rates. Thus, we require novel approaches to store and process large amounts of information at high performance. Modern quantum optics already provides some basic strategies to reach these goals. We note here, e.g. the concepts of quantum memories, qubits, entanglement, quantum computation, quantum cryptography, or single photon sources.
Many of these approaches rely on interactions between coherent radiation and quantized matter. As a specific class of coherent interactions, adiabatic passage processes combine high efficiency and pronounced robustness with regard to fluctuations in the experimental parameters. Electromagnetically-induced transparency (EIT) exhibits a prominent example for such adiabatic interactions. EIT triggered the development of many novel concepts for optical information storage. This led to the implementation of slow light, storage of light pulses in atomic coherences, and quite recently the concept of stationary light pulses (SLPs). SLPs may be understood as “freezing” or “trapping” radiation in an appropriately driven atomic medium. This is similar to storage of light in a laser cavity – but without the need for mirrors. All EIT-based effects significantly increase the interaction time of photons with the medium. Thus, also the interaction time between photons from additional radiation fields in the medium increases. At the same time incoherent absorption by the medium is suppressed. This allows for, e.g. engineering strong interactions between individual photons and thereby creating many-body systems with photons which has been attracting increasing scientific interest in recent research efforts.
The concepts of EIT, slow light, or light storage/retrieval have been extensively studied experimentally. In contrast, the quite novel concept of SLPs received only little experimental attention so far. Among others, this is due to the large optical depth, which is required for the formation of SLPs.
To achieve the highest possible optical depths and strong coupling of light and matter the route pursued in SLICA was via loading laser-cooled atoms into a hollow-core photonic crystal fiber. Such fibers allow for the simultaneous guiding of light and atoms, thereby creating the strong coupling necessary for inducing strong photon-photon interactions in the future.
During the running time of the project the following goals were achieved:
1) A world record loading efficiency of laser-cooled atoms into a hollow-core fiber photonic crystal fiber yielding a record optical depth of 1000 was demonstrated. This represents an 8-fold increase over the previous record.
2) EIT, EIT-based slow light, and for the first time ever light storage and SLPs inside a hollow-core fiber were demonstrated.
3) Temperature measurements of laser-cooled atoms using the EIT-technique were implemented.
4) Using an analogy from the field of quantum optics, a device for broad- and narrowband light polarization control was demonstrated in a sub-project dealing with applied optics.
These results pave the way towards quantum nonlinear optics based on SLPs in atomic ensembles and applications in future quantum information storage and processing.
Many of these approaches rely on interactions between coherent radiation and quantized matter. As a specific class of coherent interactions, adiabatic passage processes combine high efficiency and pronounced robustness with regard to fluctuations in the experimental parameters. Electromagnetically-induced transparency (EIT) exhibits a prominent example for such adiabatic interactions. EIT triggered the development of many novel concepts for optical information storage. This led to the implementation of slow light, storage of light pulses in atomic coherences, and quite recently the concept of stationary light pulses (SLPs). SLPs may be understood as “freezing” or “trapping” radiation in an appropriately driven atomic medium. This is similar to storage of light in a laser cavity – but without the need for mirrors. All EIT-based effects significantly increase the interaction time of photons with the medium. Thus, also the interaction time between photons from additional radiation fields in the medium increases. At the same time incoherent absorption by the medium is suppressed. This allows for, e.g. engineering strong interactions between individual photons and thereby creating many-body systems with photons which has been attracting increasing scientific interest in recent research efforts.
The concepts of EIT, slow light, or light storage/retrieval have been extensively studied experimentally. In contrast, the quite novel concept of SLPs received only little experimental attention so far. Among others, this is due to the large optical depth, which is required for the formation of SLPs.
To achieve the highest possible optical depths and strong coupling of light and matter the route pursued in SLICA was via loading laser-cooled atoms into a hollow-core photonic crystal fiber. Such fibers allow for the simultaneous guiding of light and atoms, thereby creating the strong coupling necessary for inducing strong photon-photon interactions in the future.
During the running time of the project the following goals were achieved:
1) A world record loading efficiency of laser-cooled atoms into a hollow-core fiber photonic crystal fiber yielding a record optical depth of 1000 was demonstrated. This represents an 8-fold increase over the previous record.
2) EIT, EIT-based slow light, and for the first time ever light storage and SLPs inside a hollow-core fiber were demonstrated.
3) Temperature measurements of laser-cooled atoms using the EIT-technique were implemented.
4) Using an analogy from the field of quantum optics, a device for broad- and narrowband light polarization control was demonstrated in a sub-project dealing with applied optics.
These results pave the way towards quantum nonlinear optics based on SLPs in atomic ensembles and applications in future quantum information storage and processing.