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A key requirement for implementing photonic quantum information networks is the mutual two-photon interference between photons emitted by spatially separated quantum light sources. In order to up-scale such networks, the deterministic fabrication of efficient sources of single and indistinguishable photons is of crucial importance. So far, few experiments reported on two-photon interference (TPI)...
Quantum interference forces two indistinguishable input photons to depart a beamsplitter in the same (of two possible) spatial output modes; this is known as the Hong-Ou-Mandel (HOM) effect. It provides a quantitative way of measuring the distinguishability between two photons and also has been utilised to determine their relative temporal delays [1, 2]. HOM interferometry offers numerous advantages...
We report the new method for the measurement of the phase-relaxation time T2 of a medium with femtosecond time resolution. The method is based on the effect of quantum interference of entangled photons and does not require the actual use of a femtosecond light source. The method provides the practical and cost-efficient alternative to existing methods of ultrafast time-resolved spectroscopy [1].
One of the cornerstones of quantum mechanics is that matter can possess both particle- and wave-like properties. Since the inception of quantum mechanics, such wavelike behaviour has been observed in ever more massive systems — ranging from electrons, neutrons, ultracold atoms, and even large molecules comprising many hundreds of atoms. An exciting route to further extend the exploration of quantum...
The ability to transfer entanglement over large distance is a main requirement for quantum networks. Another fundamental ingredient is the storage of such a quantum state in a quantum memory. To this end a useful resource is a photon pair for which one photon is resonant with the memory while its partner is at a low-loss telecommunication wavelength. We recently presented a photon pair source, compatible...
A single pixel Holoscopy for 3D high resolution optical imaging acquisition method is proposed. By using compressive sensing theory in holoscopy, we fully reconstruct the wave field from a single hologram with only 10% sampling ratio.
Information traffic demands have increased dramatically in recent years, leading to the so called “Capacity Crunch” in optical fiber. There are two possible ways to solve this problem. The first is using Space Division Multiplexing to increase the capacity. This requires setting up a completely new infrastructure with multimode fibers. The second is to improve the capacity of the current infrastructure...
Optical coherence tomography (OCT) is a non-invasive imaging technique with many applications and widespread use in ophthalmology [1]. The axial resolution in OCT is inversely proportional to the bandwidth of the optical source used, but the improved axial resolution comes at the price of more significant effects of dispersion stemming from the imaging system and the imaged medium. In recent years,...
Hollow-core photonic crystal fibers (HC-PCF) opened new perspectives towards multi-octave comb generation and waveform synthesis using stimulated Raman scattering (SRS) generation in gases introduced in its core [1, 2]. In the transient regime of SRS [3], a short pump pulse combined to a high gain can amplify a few spatial-temporal modes (STM) from the quantum noise. It is even possible to have only...
Segmented wave front phase measurement is a key technological topic for next generation of kHz lasers, which will be based on the combination of small-scale laser sources (fibers) before focusing on target, such as in Laser WakeField Acceleration (LWFA) [1].
The spatial structure of a photon has proved to be indispensable resource allowing the experimental realization of free-space quantum cryptography or high dimensional entanglement. Although efficient methods for manipulating spatial characteristic of individual photons can be easily transferred from the field of classical optics, their spatial structure cannot be measured using the standard interferometric...
The interference between two paths of a single photon at a double slit is widely considered to be the most paradoxical result of quantum theory. Here is a new interesting question to the phenomenon: Can a single shutter simultaneously close two slits by effectively being in a superposition of different locations? Aharonov and Vaidman have shown that it is indeed possible to construct a quantum shutter...
Heralded single-photon sources (HSPS) are widely used in experimental quantum science because they have negligibly small jitter and can therefore achieve high visibility for quantum interference. However, it is necessary to decrease the photon generation rate to suppress multi-photon components. To address this problem, two methods have been proposed and discussed: spatial (or temporal) source multiplexing...
One of the standard communication complexity problems is deciding whether bit strings held by two separate parties Alice (A) and Bob (B) are equal or different. In the simultaneous message passing model, A and B send certain information to a Referee, who makes the decision. The overall goal is to minimize the amount of communication involved while not exceeding desired error probability. This is achieved...
In recent years, the widespread availability of multi-dimensional photoelectron spectroscopy has created the opportunity to systematically study the complex interference patterns inherent to multiphoton ionization of atoms and molecules. The dominant interference mechanism in multiphoton ionization leads to discrete peaks in the photoelectron spectrum (PES) that are spaced by the photon energy of...
Weakly-fused optical fibre couplers can be simplified as a system of two optical fibre tapers, which are often called nanofibers when having sub-micron diameters. While conventional optical fibre couplers exhibit a wide spectral region of modal interference where two modes provide a continuous oscillatory behaviour associated to the large difference between phase constants of interfering supermodes...
Surface plasmon polaritons (SPPs) are bosonic quasiparticles. In the last ten years, several groups have reproduced fundamental quantum optics experiments with surface plasmons. Observation of single-plasmon states, waveparticle duality, preservation of entanglement of photons in plasmon-assisted transmission [1,2], and more recently, two-plasmon interference has been reported, revisiting with success...
Recently, multilevel-modulation formats such as quadrature phase shift keying and 16-ary quadrature amplitude modulation are being introduced into optical communication systems. Since such signal forms are susceptible to laser phase instability, it is important to identify the linewidth of lasers used in such systems. As a measurement technology, the self-heterodyne method is widely deployed [1]....
Hydrogen sulfide (H2S) is a highly toxic gas that can be frequently found in the vicinity of industrial sites such as petroleum refineries, natural gas plants, or waste water treatment facilities. Its open-path detection with sensitivities at single ppm (parts-per-million) levels is critical for safety reasons. Laser-based H2S sensing typically relies on a quartz-enhanced photo-acoustic spectroscopy...
We report new mode analysis in oscillating multi-core photonic crystal fiber laser by an interference method. In this method, we observed the output has a 67% overlap with the out-of-phase mode.
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