- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Accurate Number Densities of Ideal Photons in a One-Dimensional Barrel Cavity
摘要： Our experimental scheme is based on a barrel optical microcavity filled with a dye solution. It is found that the number of non-condensed photons is characterized by an analytical function, which involves a q-digamma function in mathematics. We employ the q-digamma function to calculate the spatial and momentum distributions of ideal photons in a one-dimensional barrel cavity. The first main finding in this paper is that the spatial and momentum distributions possess a similar profile. The second main finding is that when photons are in the normal state, the density profile exhibits Friedel oscillations. The third main finding is that when photons are in the BEC state, the density profile exhibits a sharp peak with extremely narrow width. The fourth main finding is that the central peak of the density distribution is a monotonically increasing function of the photon number N but is a monotonically decreasing function of the temperature T.
关键词： Bose-Einstein condensation,One-dimensional photons,Number densities of photons,Optical microcavity
更新于2025-09-23 15:23:52
-
A feasibility study of the time reversal violation test based on polarization of annihilation photons from the decay of ortho-Positronium with the J-PET detector
摘要： The Jagiellonian Positron Emission Tomograph (J-PET) is a novel device being developed at Jagiellonian University in Krakow, Poland based on organic scintillators. J-PET is an axially symmetric and high acceptance scanner that can be used as a multi-purpose detector system. It is well suited to pursue tests of discrete symmetries in decays of positronium in addition to medical imaging. J-PET enables the measurement of both momenta and the polarization vectors of annihilation photons. The latter is a unique feature of the J-PET detector which allows the study of time reversal symmetry violation operator which can be constructed solely from the annihilation photons momenta before and after the scattering in the detector.
关键词： Time reversal symmetry,Momenta,Polarization,Annihilation photons,J-PET detector,Discrete symmetries,Ortho-positronium
更新于2025-09-23 15:23:52
-
Rational Management of Photons for Enhanced Photocatalysis in Structurally-Colored Nanoporous Anodic Alumina Photonic Crystals
摘要： A comprehensive study on the engineering of titanium dioxide-functionalized nanoporous anodic alumina distributed Bragg reflectors (TiO2-NAA-DBRs) for photocatalysis enhanced by the “slow photon” effect is presented. The photocatalytic performance of these composite photonic crystals (PCs) is assessed by monitoring photodegradation of a variety of organic molecules with absorbance bands across the spectral regions. This study demonstrates that photocatalytic performance of TiO2-NAA-DBRs is enhanced by the “slow photon” effect when the edges of the PC’s photonic stopband (PSB) fall within the absorbance band of the organic molecules. The photocatalytic performance is significantly enhanced when the PSB’s red edge is in close proximity to the absorbance band of the organic molecules. Overall photocatalytic degradation is also dependent on the total pore length of the PC structure, charge of the organic molecules, percentage of vis-NIR irradiation and matrix complexity (i.e. interfering ions and molecules) when the PC’s PSB is partially or entirely misaligned with respect to the absorbance band of the organic molecules. Finally, the real-life application of TiO2-NAA-DBRs to degrade pollutants such as pesticides in environmental matrices is demonstrated. This study provides new insights into the development of rationally engineered, high-performing, safe and reusable photocatalyst systems.
关键词： Stopband,Pulse Anodization,Photocatalysis,Slow Photons,Photonic Crystals
更新于2025-09-23 15:23:52
-
The LXe calorimeter and the pixelated timing counter in the MEG II experiment
摘要： The MEG experiment is to look for a lepton flavor violating μ + → e+γ decay with an unprecedented sensitivity, and we set an upper limit of the branching ratio for this decay, 5.7 × 10?13 at 90% C.L. in 2013 which is a twenty times more stringent limit than the previous experiment, MEGA. Since the sensitivity improvement was limited by the accidental background, we have considered the major detector upgrade. A proposal was submitted to PSI committee, and was approved in 2013, which aims at a sensitivity enhancement of one order of magnitude compared with the current MEG experiment. Here mainly two components of the MEG detector will be introduced, a γ-ray calorimeter with 900 L of liquid xenon (LXe), and a pixelated timing counter. The LXe detector will be improved by increasing the granularity at the incident face, by replacing the current PMTs with a larger number of smaller photosensors (MPPC) and optimizing the photosensor layout also on the lateral faces. A new highly segmented, fast timing counter array will replace the old system to allow improved timing resolution capabilities.
关键词： visible and IR photons (solid-state),HPG,Large detector systems for particle and astroparticle physics,Photon detectors for UV,CZT,Gamma detectors (scintillators,HgI etc),Timing detectors
更新于2025-09-23 15:23:52
-
Direct characterization of linear and quadratically nonlinear optical systems
摘要： A central task in quantum-information processing is to characterize quantum processes. In the realm of optical quantum-information processing, this amounts to characterizing the transformations of the mode creation and annihilation operators. This transformation is unitary for linear optical systems, whereas these yield the well-known Bogoliubov transformations for systems with Hamiltonians that are quadratic in the mode operators. In this paper, we propose a shot-noise limited scheme for characterizing both these kinds of evolutions by employing a modified Mach-Zehnder interferometer. In order to characterize a N -mode device, we require O(N 2) measurements. Although it suffices to use coherent states for the characterization of linear optical systems, we additionally require single photons to characterize quadratically nonlinear optical systems.
关键词： Bogoliubov transformations,Mach-Zehnder interferometer,optical systems,quantum-information processing,coherent states,single photons
更新于2025-09-23 15:21:21
-
[Springer Theses] Quantum Confined Excitons in 2-Dimensional Materials || Introduction: 2d-Based Quantum Technologies
摘要： Framed within the growing giant of quantum technologies, with billions in expenditure world-wide and rapidly growing, we harness the exciting physics and technological promise of 2-dimensional materials to create atomically-thin quantum devices capable of emitting single photons and capturing single spins. In this thesis we present the alliance of 2d and quantum information technology - the first steps towards hybrid light-matter quantum networks set in a low power, scalable on-chip platform.
关键词： quantum technologies,single spins,single photons,quantum networks,2-dimensional materials
更新于2025-09-23 15:21:21
-
Novel method exploration of monitoring neutron beam using Cherenkov photons in BNCT
摘要： Ensuring the stability of the neutron beam during boron neutron capture therapy (BNCT) is essential. The goal of this work was to explore a novel method using Cherenkov photons for real-time monitoring of neutron beam in BNCT. The Monte Carlo toolkit Geant4, was used to calculate the Cherenkov photons and dose based on a cubic phantom and Chinese hybrid radiation phantom under di?erent conditions. Based on the study on the cubic phantom, the change of neutron beam characteristics indeed have an impact on dose, which needs quality assurance. The relationship between Cherenkov photons and gamma dose was favorable. The maximum relative variation of the generation of Cherenkov photons is approximately 3.51%, even when the relative change of boron concentration reaching 60%. However, comparing the results of the neutron beam with the original characteristics, the maximum relative variation of Cherenkov photons reaches 14.75% and 14.68% for the usage of Neuboron- spectrum and 5-degree rotation of neutron beam ?eld orientation, respectively. Therefore, the intensity and distribution of Cherenkov photons can only be observably changed by neutron beam characteristics. Based on the Chinese hybrid radiation phantom, the changes in the intensity and distribution of Cherenkov photons can also be observed inside the phantom, and these changes are evident by a detector outside the phantom. Thus, Cherenkov photons has the potential application for neutron beam monitoring.
关键词： Neutron beam,Boron neutron capture therapy,Cherenkov photons,Monitoring
更新于2025-09-23 15:21:21
-
Discrimination of entangled photon pair from classical photons by de Broglie wavelength
摘要： Quantum optics largely relies on the fundamental concept that the diffraction and interference patterns of a multi-partite state are determined by its de Broglie wavelength. in this paper we show that this is still true for a mixed state with one sub-system being in a classical coherent state and one being in entangled state. We demonstrate the quantum-classical light discrimination using de Broglie wavelength for the states with all classical parameters being the same.
关键词： entangled photons,de Broglie wavelength,quantum optics,classical photons,quantum-classical discrimination
更新于2025-09-23 15:21:01
-
Heralded single-photon and correlated-photon-pair generation via spontaneous four-wave mixing in tapered optical fibers
摘要： We study the generation of frequency nondegenerate correlated photon pairs and heralded single photons via spontaneous four-wave mixing (SFWM) in a series of identical micro- or nano?bers (MNFs). Joint spectral intensity of the biphoton ?eld generated at wavelengths of about 880 and 1310 nm has been measured under excitation by 100-ps laser pulses demonstrating good agreement with the theoretical prediction. The measured zero-time second-order autocorrelation function was about 0.2 when the emission rate of the heralded photons was of 4 Hz. The MNF-based source perfectly matches standard single-mode ?bers, which makes it compatible with the existing ?ber communication networks. In addition, SFWM observation in a series of identical MNFs allows for increasing the generation rate of single photons via spatial multiplexing.
关键词： heralded single photons,spontaneous four-wave mixing,correlated photon pairs,micro- or nano?bers,quantum optical technologies
更新于2025-09-23 15:21:01
-
Characterization of Si and SiC detectors for laser-generated plasma monitoring in short wavelength range
摘要： Silicon carbide detectors were employed to characterize the plasma produced by laser interaction with a double stream gas-pu? target source. A 10 Hz repetition rate Nd:YAG laser (1064 nm wavelength, 0.69 J pulse energy and 3 ns pulse duration) was employed to irradiate di?erent gas-pu? targets (Argon, Xenon and Sulfur hexa?uoride), at di?erent pressures (1–10 bar), emitting plasma radiation in di?erent wavelength ranges (ultraviolet, extreme ultraviolet and soft X-rays). The emission produced by the laser radiation was properly ?ltered (employing Titanium, Aluminium, Zirconium and Calcium ?uoride ?lters), to narrow down the broad-band emission of the generated plasma. The SiC detectors’ signals were compared with a calibrated traditional silicon detector evaluating their di?erences, i.e. taking into account the plasma stability, the time trace pro?le and the characteristics of the gas-pu? target source. The obtained results, which will be presented and discussed, allow to improve the geometry and con?guration of the SiC detectors avoiding saturation and charge recombination e?ects and getting a better proportionality to the energy and ?uence of the detected radiations.
关键词： X-ray detectors,Radiation monitoring,Detectors for UV, visible and IR photons,Plasma generation (laser-produced, RF, x ray-produced)
更新于2025-09-23 15:21:01