Integrated optics allow the generation and control of increasingly complex photonic states on chip based architectures. Here, we implement two entangled qutrits -a 9-dimensional quantum system -and demonstrate an exceptionally high degree of experimental control. The approach which is conceptually different to common bulk optical implementations is heavily based on methods of integrated in-fiber and on-chip technologies and further motivated by methods commonly used in today's telecommunication industry. The system is composed of an in-fiber source creating entangled qutrit states of any amplitude and phase and an on-chip integrated general Multiport enabling the realization of any desired local unitary transformation within the two qutrit 9-dimensional Hilbert space. The complete design is readily extendible towards higher-dimensions with moderate increase in complexity. Ultimately, our scheme allows for complete on-chip integration. We demonstrate the flexibility and generality of our system by realizing a complete characterization of the two qutrit space of higher-order Einstein-Podolsky-Rosen correlations. * Corresponding
Integrated photonic circuits offer the possibility for complex quantum optical experiments in higher-dimensional photonic systems. However, the advantages of integration and scalability can only be fully utilized with the availability of a source for higher-dimensional entangled photons. Here, a novel fiber integrated source for path-entangled photons in the telecom band at 1.55µm using only standard fiber technology is presented. Due to the special design the source shows good scalability towards higher-dimensional entangled photonic states (quNits), while path entanglement offers direct compatibility with on-chip path encoding. We present an experimental realization of a path-entangled two-qubit source. A very high quality of entanglement is verified by various measurements, i.a. a tomographic state reconstruction is performed leading to a background corrected fidelity of (99.45 0.06)% . Moreover, we describe an easy method for extending our source to arbitrarily high dimensions.
Laser produced ion beams have a large divergence angle and a wide energy spread. To our knowledge, this is the first demonstration of collimation and monochromatisation of laser accelerated proton beams, using a permanent quadrupole magnet lens system. It acts as a tunable band pass filter by collimating or focusing the protons with the same energy. Because it gathers nearly the whole proton emission, a strong enhancement of the beam density appears. For the collimated beam, an increase of the proton density in the (3.7 ± 0.3) MeV energy band up to a factor of ~30, from possible 40, relative to the non-collimated beam is demonstrated. With the help of this simple, reliable, and well established technique new perspectives will be opened for science and technology, monoenergetic ion beams can be attained in any lab, where a source of laser accelerated ions exist. This finding enables to apply afterward well known beam steering techniques to the formed ion beam, which are applied in conventional accelerators to manipulate the beam parameters or to transport the beams and make them use in many application.
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