scholarly journals Two-photon quantum interference and entanglement at 2.1 μm

2020 ◽  
Vol 6 (13) ◽  
pp. eaay5195 ◽  
Author(s):  
Shashi Prabhakar ◽  
Taylor Shields ◽  
Adetunmise C. Dada ◽  
Mehdi Ebrahim ◽  
Gregor G. Taylor ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Communication Systems ◽  
Near Infrared ◽  
Single Photon ◽  
Satellite Communications ◽  
Optical Systems ◽  
Fiber Communication ◽  
Spectral Window ◽  
Mid Infrared ◽  
Two Photon

Quantum-enhanced optical systems operating within the 2- to 2.5-μm spectral region have the potential to revolutionize emerging applications in communications, sensing, and metrology. However, to date, sources of entangled photons have been realized mainly in the near-infrared 700- to 1550-nm spectral window. Here, using custom-designed lithium niobate crystals for spontaneous parametric down-conversion and tailored superconducting nanowire single-photon detectors, we demonstrate two-photon interference and polarization-entangled photon pairs at 2090 nm. These results open the 2- to 2.5-μm mid-infrared window for the development of optical quantum technologies such as quantum key distribution in next-generation mid-infrared fiber communication systems and future Earth-to-satellite communications.

scholarly journals All-Optical Modulation Technology Based on 2D Layered Materials

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 92
Author(s):  
Hongyan Yang ◽  
Yunzheng Wang ◽  
Zian Cheak Tiu ◽  
Sin Jin Tan ◽  
Libo Yuan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Communication Systems ◽  
Near Infrared ◽  
2D Materials ◽  
Optical Devices ◽  
Optical Systems ◽  
Optical Modulation ◽  
Wavelength Converter ◽  
Optical Modulators ◽  
All Optical

In the advancement of photonics technologies, all-optical systems are highly demanded in ultrafast photonics, signal processing, optical sensing and optical communication systems. All-optical devices are the core elements to realize the next generation of photonics integration system and optical interconnection. Thus, the exploration of new optoelectronics materials that exhibit different optical properties is a highlighted research direction. The emerging two-dimensional (2D) materials such as graphene, black phosphorus (BP), transition metal dichalcogenides (TMDs) and MXene have proved great potential in the evolution of photonics technologies. The optical properties of 2D materials comprising the energy bandgap, third-order nonlinearity, nonlinear absorption and thermo-optics coefficient can be tailored for different optical applications. Over the past decade, the explorations of 2D materials in photonics applications have extended to all-optical modulators, all-optical switches, an all-optical wavelength converter, covering the visible, near-infrared and Terahertz wavelength range. Herein, we review different types of 2D materials, their fabrication processes and optical properties. In addition, we also summarize the recent advances of all-optical modulation based on 2D materials. Finally, we conclude on the perspectives on and challenges of the future development of the 2D material-based all-optical devices.

scholarly journals The Misuse of the No-Communication Theorem by Ghirardi - In The Analysis of a Non-Local Communication SystemThat Effectively Swaps Distant Joint Entanglement to Local Path Entanglement of an Interferometer

2019 ◽  
Author(s):  
Remi Cornwall
Keyword(s):  
Communication Systems ◽  
Single Photon ◽  
Entanglement Swapping ◽  
Schmidt Decomposition ◽  
Partial Trace ◽  
Local Communication ◽  
Two Photon ◽  
Non Local ◽  
Local Path ◽  
Joint Evolution

This paper is in response to a critique of the author’s earlier papers on the matter of a non-local communication system by Ghirardi. The setup has merit for not apparently falling for the usual pitfalls of putative communication schemes, as espoused by the No-communication theorem (NCT) - that of non-factorisability. The enquiry occurred from the investigation of two interferometer based communication systems: one two-photon entanglement, the other single-photon path entanglement. Both systems have two parties: a sender (“Alice”) who transmits or absorbs her particle and a receiver (“Bob”) who has an interferometer, which can discern a pure or mixed state, ahead of his detector. Ghirardi used the density matrix and found that the system wasn’t factorisable; this was seen as a fulfilment of the NCT. We revisit the analysis and say quite simply that Ghirardi is mistaken. The system is rendered factorisable by a Schmidt decomposition and entanglement swapping to “which path information” of the interferometer; also one must consider the joint evolution before taking the partial trace. Ghirardi’s misuse, by the inapplicability of the NCT in this situation, renders this general prohibitive bar incomplete or entirely wrong.

scholarly journals Photon engineering for quantum information processing

2003 ◽  
Vol 3 (special) ◽  
pp. 480-502
Author(s):  
A.B. U'Ren ◽  
K. Banaszek ◽  
I.A. Walmsley
Keyword(s):  
Information Processing ◽  
Quantum Information ◽  
Quantum Interference ◽  
Quantum Information Processing ◽  
Logic Gate ◽  
Optical Systems ◽  
Two Photon ◽  
Entangled Photon Pairs ◽  
Available Technology ◽  
Photon States

We study distinguishing information in the context of quantum interference involving more than one parametric downconversion (PDC) source and in the context of generating polarization-entangled photon pairs based on PDC. We arrive at specific design criteria for two-photon sources so that when used as part of complex optical systems, such as photon-based quantum information processing schemes, distinguishing information between the photons is eliminated guaranteeing high visibility interference. We propose practical techniques which lead to suitably engineered two-photon states that can be realistically implemented with available technology. Finally, we study an implementation of the nonlinear-sign shift (NS) logic gate with PDC sources and show the effect of distinguishing information on the performance of the gate.

Multi-Photon Fluorescence Spectroum of Common Nucleic Acid Probes

2000 ◽  
Vol 6 (S2) ◽  
pp. 820-821
Author(s):  
P. C. Cheng ◽  
B. L. Lin ◽  
F. J. Kao ◽  
C. K. Sun ◽  
I. Johnson
Keyword(s):  
Fluorescence Microscopy ◽  
Fluorescent Probes ◽  
Fluorescence Spectra ◽  
Near Infrared ◽  
Single Photon ◽  
Spectral Response ◽  
Two Photon ◽  
Photon Excitation ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Fluorescent probes are commonly used in biological fluorescence microscopy for tracking specific structures and sub-cellular compartments, and for indicating cellular ionic conditions. Recent development in multi-photon fluorescence microscopy has greatly expanded the usage of fluorescent probes in biomedical research. Considering its non-linear nature, two-photon excitation may generate very different fluorescence spectral response in the sample when compared with single photon excitation. It is thus necessary to measure the two-photon spectra of various fluorescent probes, so that two-photon fluorescence microscopy may be operated effectively and the images properly interpreted. This report represents the first installment of a continued effort in characterizing the multi-photon fluorescence spectra of commonly used bio-probes.Two-photon fluorescence spectra excited with near infrared at 780nm were obtained with a SpectraPro-500 spectrophotometer (Acton Research) equipped with a TE-cooled PMT and coupled to a Spectra-Physics Tsunami Ti-sapphire laser pumped by a Coherent Verdi solid-state laser operated at 85MHz, l00fs pulse.

scholarly journals Observing the quantum Cheshire cat effect with noninvasive weak measurement

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yosep Kim ◽  
Dong-Gil Im ◽  
Yong-Su Kim ◽  
Sang-Wook Han ◽  
Sung Moon ◽  
...  
Keyword(s):  
Quantum Interference ◽  
Single Photon ◽  
Polarization State ◽  
Physical Property ◽  
Spatial Separation ◽  
Weak Measurement ◽  
Classical Systems ◽  
Two Photon ◽  
Classical Waves ◽  
Quantum Phenomena

AbstractOne of the common conceptions of nature, typically derived from the experiences with classical systems, is that attributes of the matter coexist with the substance. In the quantum regime, however, the quantum particle itself and its physical property may be in spatial separation, known as the quantum Cheshire cat effect. While there have been several reports to date on the observation of the quantum Cheshire cat effect, all such experiments are based on first-order interferometry and destructive projection measurement, thus allowing simple interpretation due to measurement-induced disturbance and also subject to trivial interpretation based on classical waves. In this work, we report an experimental observation of the quantum Cheshire cat effect with noninvasive weak quantum measurement as originally proposed. The use of the weak-measurement probe has allowed us to identify the location of the single photon and that of the disembodied polarization state in a quantum interferometer. The weak-measurement probe based on two-photon interference makes our observation unable to be explained by classical physics. We furthermore elucidate the quantum Cheshire cat effect as quantum interference of the transition amplitudes for the photon and the polarization state which are directly obtained from the measurement outcomes or the weak values. Our work not only reveals the true quantum nature of Cheshire cat effect but also sheds light on a comprehensive understanding for the counter-intuitive quantum phenomena.

SIMULATION STUDY OF PROPAGATION OF PULSES IN OPTICAL FIBER COMMUNICATION SYSTEMS USING SOBOLEV GRADIENT AND SPLIT-STEP FOURIER METHODS

2009 ◽  
Vol 06 (01) ◽  
pp. 119-130 ◽  
Author(s):  
NAUMAN RAZA ◽  
SULTAN SIAL ◽  
SHAHID S. SIDDIQI
Keyword(s):  
Communication Systems ◽  
Optical Fiber Communication ◽  
Optical Systems ◽  
Computationally Efficient ◽  
Fiber Communication ◽  
Wide Range ◽  
Sobolev Gradients ◽  
Sobolev Gradient ◽  
Gradient Technique ◽  
The One

The one-dimensional nonlinear Schrödinger equation (NLSE) has a wide range of applications in nonlinear optical and laser physics. The design of new optical systems requires analysis of the propagation characteristics of pulses in the fiber media. In this paper, the Sobolev gradient technique has been used for numerical solution of the NLSE. We show that gradients in a suitably chosen Sobolev space (Sobolev gradients) can be used in finite difference settings in a computationally efficient way to approximate the profile of a pulse given by the NLSE.

scholarly journals Experimental interference of uncorrelated photons

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Heonoh Kim ◽  
Osung Kwon ◽  
Han Seb Moon
Keyword(s):  
Quantum Interference ◽  
Single Photon ◽  
Quantum Effect ◽  
Photon Counting ◽  
Interference Phenomenon ◽  
Single Photon Counting ◽  
Two Photon ◽  
Quantum Interference Effect ◽  
The Individual ◽  
Photon States

AbstractThe distinguishing of the multiphoton quantum interference effect from the classical one forms one of the most important issues in modern quantum mechanics and experimental quantum optics. For a long time, the two-photon interference (TPI) of correlated photons has been recognized as a pure quantum effect that cannot be simulated with classical lights. In the meantime, experiments have been carried out to investigate the classical analogues of the TPI. In this study, we conduct TPI experiments with uncorrelated photons with different center frequencies from a luminescent light source, and we compare our results with the previous ones of correlated photons. The observed TPI fringe can be expressed in the form of three phase terms related to the individual single-photon and two-photon states, and the fringe pattern is strongly affected by the two single-photon-interference fringes and also by their visibilities. With the exception of essential differences such as valid and accidental coincidence events within a given resolving time and the two-photon spectral bandwidth, the interference phenomenon itself exhibits the same features for both correlated and uncorrelated photons in the single-photon counting regime.

scholarly journals A Comparative Study of SPM, XPM in Er-Yb Co-doped Fiber

2021 ◽  
Author(s):  
ADITYA KUMAR ◽  
Gausia Qazi
Keyword(s):  
Optical Fiber ◽  
Comparative Study ◽  
Phase Modulation ◽  
Communication Systems ◽  
Optical Fiber Communication ◽  
Optical Systems ◽  
Fiber Communication ◽  
Non Linear ◽  
Linear Effects ◽  
Co Doped

Optical fiber communication has been the most versatile and revolutionary medium of communication that has helped in connecting millions of people across the globe. These traits have seen tremendous development in the sector of optical fiber communication. There are now many desired qualities that are expected out of an optical fiber communication like large transmission capacity and a lesser amount of losses. Communication systems operating with higher transmission rates have found an essential role of non-linear fiber optics. The behaviour of light in non-linear media is dealt with non-linear optics. Cross-Phase Modulation (XPM) and Self-Phase Modulation (SPM) are a few non-linearities occurring in the optical fiber. Non-linear effects reduce the performances of optical fibers. In this paper, a comparative study of non-linear effects in Er-Yb co-doped Fiber are reviewed using simulation and the results are compared with optical systems utilizing normal fiber. Benefits of utilizing Er-Yb fiber has been demonstrated by analysing effective systems comprising the Er-Yb co-doped fiber and their ability to mitigate the non-linearities.

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