المؤلفون: Stiller, Birgit, Jaksch, Kevin, Piotrowski, Johannes, Merklein, Moritz, Schmidt, Mikolaj K., Vu, Khu, Ma, Pan, Madden, Stephen, Steel, Michael J., Poulton, Christopher G., Eggleton, Benjamin J.

مصطلحات موضوعية: Physics - Optics, Quantum Physics

الوصف: Signal processing based on stimulated Brillouin scattering (SBS) is limited by the narrow linewidth of the optoacoustic response, which confines many Brillouin applications to continuous wave signals or optical pulses longer than several nanoseconds. In this work, we experimentally demonstrate Brillouin interactions at the 150 ps time scale and a delay for a record 15 ns which corresponds to a delay of 100 pulse widths. This breakthrough experimental result was enabled by the high local gain of the chalcogenide waveguides as the optoacoustic interaction length reduces with pulse width. We successfully transfer 150ps-long pulses to traveling acoustic waves within a Brillouin-based memory setup. The information encoded in the optical pulses is stored for 15 ns in the acoustic field. We show the retrieval of eight amplitude levels, multiple consecutive pulses and low distortion in pulse shape. The extension of Brillouin-based storage to the ultra-short pulse regime is an important step for the realisation of practical Brillouin-based delay lines and other optical processing applications.
Comment: 6 pages, 6 figures

الوصول الحر: http://arxiv.org/abs/2308.01009Test

المؤلفون: Molignini, Paolo, Lévêque, Camille, Kessler, Hans, Jaksch, Dieter, Chitra, R., Lode, Axel U. J.

المصدر: Phys. Rev. A 106, L011701 (2022)

مصطلحات موضوعية: Condensed Matter - Quantum Gases, Physics - Atomic Physics, Physics - Optics, Quantum Physics

الوصف: We study a one-dimensional array of bosons with infinite-range interactions mediated by a laser-driven dissipative optical cavity. The cavity-mediated infinite-range interactions open up a new pathway to fermionization, hitherto only known for dipolar bosons due to their long-range interactions. In parameter ranges attainable in state-of-the-art experiments, we systematically compare observables for bosons and fermions with infinite-range interactions. At large enough laser pump power, many observables, including density distributions in real and momentum space, correlation functions, eigenvalues of the one-body density matrix, and superradiance order parameter, become identical for bosons and fermions. We map out the emergence of this cavity-induced fermionization as a function of pump power and contact interactions. We discover that cavity-mediated interactions can compensate a reduction by several orders of magnitude in the strength of the contact interactions needed to trigger fermionization.
Comment: main text: 7 pages, 3 figures - supplement: 7 pages, 4 figures

الوصول الحر: http://arxiv.org/abs/2107.04040Test

المؤلفون: Muñoz, Carlos Sánchez, Jaksch, Dieter

مصطلحات موضوعية: Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Atomic Physics, Physics - Optics

الوصف: We introduce the concept of a squeezed laser, in which a squeezed cavity mode develops a macroscopic photonic occupation due to stimulated emission. Above the lasing threshold, the emitted light retains both the spectral purity inherent of a laser and the photon correlations characteristic of a photonic mode with squeezed quadratures. Our proposal, which can be implemented in optical setups, relies on the parametric driving of the cavity and dissipative stabilization by a broadband squeezed vacuum. The squeezed laser can find applications that go beyond those of standard lasers thanks to the squeezed character, such as the direct application in Michelson interferometry beyond the standard quantum limit, or its use in atomic metrology.
Comment: Additions to second version: effects of intra-cavity losses; symmetry-broken solutions; spectrum of squeezing; operation in a Michelson interferometer

الوصول الحر: http://arxiv.org/abs/2008.02813Test

المؤلفون: Popp, Alexandra, Distler, Victor, Jaksch, Kevin, Sedlmeir, Florian, Müller, Christian R., Haarlammert, Nicoletta, Schreiber, Thomas, Marquardt, Christoph, Tünnermann, Andreas, Leuchs, Gerd

المصدر: Appl. Phys. B 126, 130 (2020)

مصطلحات موضوعية: Physics - Optics, Quantum Physics

الوصف: We investigate the frequency-resolved intensity noise spectrum of an Yb-doped fiber amplifier down to the fundamental limit of quantum noise. We focus on the kHz and low MHz frequency regime with special interest in the region between 1 and 10 kHz. Intensity noise levels up to >60 dB above the shot noise limit are found, revealing great optimization potential. Additionally, two seed lasers with different noise characteristics were amplified, showing that the seed source has a significant impact and should be considered in the design of high power fiber amplifiers.

الوصول الحر: http://arxiv.org/abs/1908.00756Test

المؤلفون: Schlawin, Frank, Dietrich, Anastasia S. D., Kiffner, Martin, Cavalleri, Andrea, Jaksch, Dieter

المصدر: Phys. Rev. B 96, 064526 (2017)

مصطلحات موضوعية: Condensed Matter - Superconductivity, Physics - Optics

الوصف: We theoretically show that terahertz pulses with controlled amplitude and frequency can be used to switch between stable transport modes in layered superconductors, modelled as stacks of Josephson junctions. We find pulse shapes that deterministically switch the transport mode between superconducting, resistive and solitonic states. We develop a simple model that explains the switching mechanism as a destablization of the centre of mass excitation of the Josephson phase, made possible by the highly non-linear nature of the light-matter coupling.

الوصول الحر: http://arxiv.org/abs/1707.07459Test

المؤلفون: Han, Jingshan, Vogt, Thibault, Gross, Christian, Jaksch, Dieter, Kiffner, Martin, Li, Wenhui

المصدر: Phys. Rev. Lett. 120, 093201 (2018)

مصطلحات موضوعية: Physics - Atomic Physics, Physics - Optics

الوصف: We present an experimental demonstration of converting a microwave field to an optical field via frequency mixing in a cloud of cold $^{87}$Rb atoms, where the microwave field strongly couples to an electric dipole transition between Rydberg states. We show that the conversion allows the phase information of the microwave field to be coherently transferred to the optical field. With the current energy level scheme and experimental geometry, we achieve a photon conversion efficiency of ~0.3% at low microwave intensities and a broad conversion bandwidth of more than 4 MHz. Theoretical simulations agree well with the experimental data, and indicate that near-unit efficiency is possible in future experiments.
Comment: 5 pages, 4 figures

الوصول الحر: http://arxiv.org/abs/1701.07969Test

المؤلفون: Rajasekaran, Srivats, Casandruc, Eliza, Laplace, Yannis, Nicoletti, Daniele, Gu, Genda D., Clark, Stephen R., Jaksch, Dieter, Cavalleri, Andrea

المصدر: Nat. Phys. 12, 1012, 2016

مصطلحات موضوعية: Condensed Matter - Superconductivity, Physics - Optics

الوصف: Many applications in photonics require all-optical manipulation of plasma waves, which can concentrate electromagnetic energy on sub-wavelength length scales. This is difficult in metallic plasmas because of their small optical nonlinearities. Some layered superconductors support weakly damped plasma waves, involving oscillatory tunneling of the superfluid between capacitively coupled planes. Such Josephson plasma waves (JPWs) are also highly nonlinear, and exhibit striking phenomena like cooperative emission of coherent terahertz radiation, superconductor-metal oscillations and soliton formation. We show here that terahertz JPWs in cuprate superconductors can be parametrically amplified through the cubic tunneling nonlinearity. Parametric amplification is sensitive to the relative phase between pump and seed waves and may be optimized to achieve squeezing of the order parameter phase fluctuations or single terahertz-photon devices.
Comment: 25 pages, 9 figures

الوصول الحر: http://arxiv.org/abs/1511.08378Test