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Homodyne detection [1] is a typical continuous-variable measurement scheme, ubiquitously used in quantum optics and quantum information. A conventional homodyne detector performs a projective measurement onto a quadrature of the electromagnetic field mode, thus yielding a continuously distributed measurement outcome. The outcome distribution is the marginal of the Wigner function of the state. Homodyne...
Quantum key distribution (QKD) has raised increased attention over the past years as one of the most attractive quantum technologies for practical implementation. QKD has already been implemented in intra-city networks all around the world. But up to now, bridging global distances with quantum communication remains an outstanding challenge. A promising candidate to provide this link is via optical...
Optically active spins in solid-state are of interest for their potential use in a variety of future technologies. These range from quantum information processors to magnetic and electric field sensors at the nanoscale. Typically, dark paramagnetic spins in the solid-state host lattice cause quantum decoherence of the bright spin of interest. However, if these dark spins can be brought under control...
Research in micro-structured light has recently provided several exciting outcomes i.e., microscopy though turbid media or parallel micro-structuring of materials. Basically, applications on this topic rely on the use of spatial light modulators (SLM) for carrying out laser beam control at micrometric level. In this contribution we present simple and useful methods for both calibration and encoding...
Their inherently broadband gain and high value of the third order nonlinearity makes quantum cascade lasers (QCLs) ideal candidates for frequency comb generation in the terahertz (THz) and mid-infrared (midIR) spectral ranges. In recent years, it has been demonstrated that free running QCLs can produce broad comb spectra, even without any special endeavour to induce phase-locking of the lasing modes...
The photonic crystal (PhC) membrane represents a platform for planar integration of components, where cavities and waveguides may play a key role in realizing compact optical components with classical functionality such as switches, lasers, and amplifiers or quantum optical functionality such as integrated sources of quantum light. By leaving out a row of holes in an otherwise perfect PhC membrane...
We are working on hybrid quantum information processing, which combines two methodologies of quantum information processing — qubit and continuous variable (CV) [1]. More precisely, we encode logical qubits by using CV methodology and utilize CV quantum processors for the realization of a fault-tolerant large-scale universal optical quantum computer. The advantage of this methodology is that we can...
Continuous monitoring or tracking of a quantum system is essential to high-sensitivity measurement of time-varying quantities. We estimate spin precession of a magnetically-sensitive atomic ensemble by measuring spin projectors Fα at different times. Such projectors do not commute, and thus quantum measurement back-action (QMBA) necessarily enters the spin measurement record, introducing errors and...
Authentication of people or objects using physical keys is insecure against secret duplication. Physical unclonable functions (PUF) are special physical keys that are assumed to be unclonable due to the large number of degrees of freedom in their manufacturing [1]. Opaque scattering media, such as white paint and teeth, comprise of millions of nanoparticles in a random arrangement. Under coherent...
Technology for self-driving vehicles is currently under heavy development. Reliable autonomous driving requires precise information from different sensors, in order to establish a realistic and accurate model of the vehicle's environment. Time-of-Flight (ToF) sensors can contribute valuable information to such a vehicle's sensor network [1]. The influence of weather effects, in particular rain droplets,...
The emission and propagation of light in disordered media has always been a topic of interest in science, mainly because in nature this is the most common way of light emission and propagation. This research topic received a particular attention after the report of the first highly efficient random laser (RL) [1]. Indeed a large number of investigations discussing the fundamentals and the applications...
The Petawatt Field Synthesizer (PFS) is an OPCPA driven light source that is currently being developed at the Max-Planck-Institut für Quantenoptik in Garching, Germany. The target parameters are few-cycle, waveform-controlled light pulses with a repetition rate of 10 Hz and a peak power in the Petawatt regime [1]. The system relies on a cascaded broadband OPCPA that is pumped by a picosecond, all-diode-pumped...
Vertical-cavity surface-emitting lasers (VCSELs) are widely used in short-range optical data transmission and optical sensing. Tailored heating and infrared illumination with large two-dimensional parallel-driven VCSEL arrays are gaining more and more attention. In the latter fields as well as in high-speed datacom the laser performance is limited by internal heating at high operating currents or...
The emergence of long range phase coherence among random nonlinear waves is a fascinating effect that characterizes many fundamental phenomena. For instance, the condensation of classical waves [1,2] is an important example of self-organization process that generates lot of interest as a classical analogue of quantum Bose-Einstein condensation. Wave condensation is known to be characterized by the...
In optomechanical systems, co-localizing light and mechanical oscillations at the nanoscale can lead to strong interaction between photons and phonons. Such optomechanical coupling enables sensitive detection of nanoscale motion, as well as control of the motion through optical forces down to the quantum level [1]. In the vast majority of cases, the optomechanical coupling can be regarded as linear...
Optical diffraction tomography provides a powerful tool for imaging the 3-D refractive index (RI) distribution. However the method suffers from two major issues. The first one is the missing cone problem that comes from limited illumination angles. The missing cone problem can be dealt with sparsity based regularization [1]. The second problem is the nonlinear relationship between the refractive index...
The presence of specimen-induced aberrations within a tissue limits the performance of multiphoton microscopy, especially at deeper layers. Optical sectioning capabilities and maximum penetration depth are noticeable affected, and both contrast and resolution of the recorded images are reduced. Adaptive optics has been used to correct or minimize these aberrations. However plane-by-plane measurements...
Quantum technology is a fundamentally new way of harnessing Nature and it has potential for a truly revolutionary innovation and promise the next generation of products with exciting and astounding properties that will affect our lives profoundly. They will have a great influence in defence, aerospace, energy and telecommunications sectors. If this process is to continue in the future, new, quantum...
Adaptive optics loops are now widely implemented on high power laser chains and several industrial solutions exist which are optimized for their specific constrains. However the main goal for adaptive optics loop implementation is to optimize the interaction between laser and matter (gas or solid). In particular, one parameter to optimize for loop convergence is the intensity at the focus of the off-axis...
Extended-cavity quantum cascade lasers (EC-QCLs) enable mode-hope-free frequency sweeps in the mid-infrared region over ranges in excess of 100 cm−1, at speeds up to 1 THz/s and with a 100-mW optical power level. This makes them ideally suited for broadband absorption spectroscopy and for the simultaneous detection of multiple gases. On the other hand, their use for precision spectroscopy has been...
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