35 research outputs found
Squeezing in a nonlocal photon fluid
Quantum fluids of light are an emerging tool employed in quantum many-body
physics. Their amazing properties and versatility allow using them in a wide
variety of fields including gravitation, quantum information and simulation.
However the implications of the quantum nature of light in the nonlinear
optical propagation are still missing many features. We theoretically predict
classical spontaneous squeezing of a photon fluid in a nonlocal nonlinear
medium. By using the so called Gamow vectors, we show that the quadratures of a
coherent state get squeezed and that a maximal squeezing power exists. Our
analysis holds true for temporal and spatial optical propagation in highly
nonlocal regime. These results open a new scenario in quantum photon fluids and
may lead to novel applications in fields like metrology and analogues of
quantum gravity.Comment: 6 pages, 2 figure
Zel'dovich amplification in a superconducting circuit
Zel'dovich proposed that electromagnetic (EM) waves with angular momentum
reflected from a rotating metallic, lossy cylinder will be amplified. However,
we are still lacking a direct experimental EM-wave verification of this
fifty-year old prediction due to the challenging conditions in which the
phenomenon manifests itself: the mechanical rotation frequency of the cylinder
must be comparable with the EM oscillation frequency. Here we propose an
experimental approach that solves this issue and is predicted to lead to a
measurable Zel'dovich amplification with existing superconducting circuit
technology. We design a superconducting circuit with low frequency EM modes
that couple through free-space to a magnetically levitated and spinning
micro-sphere placed at the center of the circuit. We theoretically estimate the
circuit EM mode gain and show that rotation of the micro-sphere can lead to
experimentally observable amplification, thus paving the way for the first
EM-field experimental demonstration of Zel'dovich amplification.Comment: 16 pages, 8 figure
Sine-Gordon soliton as a model for Hawking radiation of moving black holes and quantum soliton evaporation
The intriguing connection between black holes' evaporation and physics of
solitons is opening novel roads to finding observable phenomena. It is known
from the inverse scattering transform that velocity is a fundamental parameter
in solitons theory. Taking this into account, the study of Haw\-king radiation
by a moving soliton gets a growing relevance. However, a theoretical context
for the description of this phenomenon is still lacking. Here, we adopt a
soliton geometrization technique to study the quantum emission of a moving
soliton in a one-dimensional model. Representing a black hole by the one
soliton solution of the sine-Gordon equation, we consider Haw\-king emission
spectra of a quantized massless scalar field on the soliton-induced metric. We
study the relation between the soliton velocity and the black hole temperature.
Our results address a new scenario in the detection of new physics in the
quantum gravity panorama.Comment: 8 pages, 4 figure
Penrose Superradiance in Nonlinear Optics
Particles or waves scattered from a rotating black hole can be amplified
through the process of Penrose superradiance, though this cannot currently be
observed in an astrophysical setting. However, analogue gravity studies can
create generic rotating geometries exhibiting an ergoregion, and this led to
the first observation of Penrose superradiance as the over-reflection of water
waves from a rotating fluid vortex. Here we theoretically demonstrate that
Penrose superradiance arises naturally in the field of nonlinear optics. In
particular, we elucidate the mechanism by which a signal beam can experience
gain or amplification as it glances off a strong vortex pump beam in a
nonlinear defocusing medium. This involves the trapping of negative norm modes
in the core of the pump vortex, as predicted by Penrose, which in turn provides
a gain mechanism for the signal beam. Our results elucidate a new regime of
nonlinear optics involving the notion of an ergoregion, and provide further
insight into the processes involved in Penrose superradiance.Comment: 1 figure, 7 page
Time-of-flight imaging at 10 ps resolution with an ICCD camera
ICCD cameras can record low light events with extreme temporal resolution. Thus, they are used in a variety of bio-medical applications for single photon time of flight measurements and LIDAR measurements. In this paper, we present a method which allows improvement of the temporal resolution of ICCD cameras down to 10 ps (from the native 200 ps of our model), thus placing ICCD cameras at a better temporal resolution than SPAD cameras and in direct competition with streak cameras. The higher temporal resolution can serve for better tracking and visualization of the information carried in time-of-flight measurements
Temperature behavior of optical absorption bands in colored LiF crystals
We measured the optical absorption spectra of thermally treated, gamma irradiated LiF crystals, as a function of temperature in the range 16–300 K. The temperature dependence of intensity, peak position and bandwidth of F and M absorption bands were obtained. Keywords: Lithium fluoride, Optical absorption, Low temperature, Color center
Physical realization of the Glauber quantum oscillator
More than thirty years ago Glauber suggested that the link between the reversible microscopic and the irreversible macroscopic world can be formulated in physical terms through an inverted harmonic oscillator describing quantum amplifiers. Further theoretical studies have shown that the paradigm for irreversibility is indeed the reversed harmonic oscillator. As outlined by Glauber, providing experimental evidence of these idealized physical systems could open the way to a variety of fundamental studies, for example to simulate irreversible quantum dynamics and explain the arrow of time. However, supporting experimental evidence of reversed quantized oscillators is lacking. We report the direct observation of exploding n = 0 and n = 2 discrete states and Γ0 and Γ2 quantized decay rates of a reversed harmonic oscillator generated by an optical photothermal nonlinearity. Our results give experimental validation to the main prediction of irreversible quantum mechanics, that is, the existence of states with quantized decay rates. Our results also provide a novel perspective to optical shock-waves, potentially useful for applications as lasers, optical amplifiers, white-light and X-ray generation
Optothermal nonlinearity of silica aerogel
The authors acknowledge support from EPSRC (EP/J004200/1), the Templeton Foundation (grant number 58277) and the ERC project VANGUARD (grant number 664782).We report on the characterization of silica aerogel thermal optical nonlinearity, obtained by z-scan technique. The results show that typical Silica Aerogels have nonlinear optical coefficient similar to that of glass (≃ 10-12m2/W), with negligible optical nonlinear absorption. The nonlinear coefficient can be increased to values in the range of 10-10m2/W by embedding an absorbing dye in the Aerogel. This value is one order of magnitude higher than that observed in the pure dye and in typical highly nonlinear materials like liquid crystals.PostprintPeer reviewe