scholarly journals Topological protection versus degree of entanglement of two-photon light in photonic topological insulators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Konrad Tschernig ◽  
Álvaro Jimenez-Galán ◽  
Demetrios N. Christodoulides ◽  
Misha Ivanov ◽  
Kurt Busch ◽  
...  

AbstractTopological insulators combine insulating properties in the bulk with scattering-free transport along edges, supporting dissipationless unidirectional energy and information flow even in the presence of defects and disorder. The feasibility of engineering quantum Hamiltonians with photonic tools, combined with the availability of entangled photons, raises the intriguing possibility of employing topologically protected entangled states in optical quantum computing and information processing. However, while two-photon states built as a product of two topologically protected single-photon states inherit full protection from their single-photon “parents”, a high degree of non-separability may lead to rapid deterioration of the two-photon states after propagation through disorder. In this work, we identify physical mechanisms which contribute to the vulnerability of entangled states in topological photonic lattices. Further, we show that in order to maximize entanglement without sacrificing topological protection, the joint spectral correlation map of two-photon states must fit inside a well-defined topological window of protection.

2021 ◽  
Author(s):  
Heonoh Kim ◽  
Osung Kwon ◽  
Han Seb Moon

Abstract Multiphoton interference is an important phenomenon in modern quantum mechanics and experimental quantum optics, and it is fundamental for the development of quantum information science and technologies. Over the last three decades, several theoretical and experimental studies have been performed to understand the essential principles underlying such interference and to explore potential applications. Recently, the two-photon interference (TPI) of phase-randomized weak coherent states has played a key role in the realization of long-distance quantum communication based on the use of classical light sources. In this context, we investigated TPI experiments with weak coherent pulses and quantitatively analyzed the results in terms of the single- and coincidence-counting rates and one- and two-photon interference-fringe shapes. We experimentally examined the Hong-Ou-Mandel-type TPI of phase-randomized weak coherent pulses to compare the TPI effect at the single-photon level with that of correlated photons. Further experiments were also performed with two temporally- and spatially separated weak coherent pulses. Although the observed interference results, including the results of visibility and fringe shape, can be suitably explained by classical intensity correlation, the physics underlying the TPI effect needs to be interpreted as the interference between the two-photon states at the single-photon level within the utilized interferometer. The results of this study can provide a more comprehensive understanding of the TPI of coherent light at the single-photon level.


2020 ◽  
Vol 35 (19) ◽  
pp. 2050158
Author(s):  
Xue-Xiang Xu ◽  
Hong-Chun Yuan

Based on a conditional interferometry proposed by Paris [Phys. Rev. A 62, 033813 (2000)], we prepare any chosen superposition of the vacuum, one-photon, and two-photon states, which is truncating from an input coherent state. Feeding two perfect single-photon states and a coherent state into the interferometry and employing two one-photon detections, the conditional state can be obtained in the signal port. Ideal and realistic features of the one-photon counting are taken into account together with the effect on the fidelity between the ideal state and the realistic case. The ideal state is just a particular case of the realistic state with the unit efficiency. We study the antibunching effect and Wigner function of the generated states. The results show that the generated states will exhibit their specular character.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Heonoh Kim ◽  
Osung Kwon ◽  
Han Seb Moon

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.


2013 ◽  
Vol 58 (3) ◽  
pp. 268-277
Author(s):  
I.S. Dotsenko ◽  
◽  
R.S. Korobka ◽  
Keyword(s):  

Author(s):  
V. Pouget ◽  
E. Faraud ◽  
K. Shao ◽  
S. Jonathas ◽  
D. Horain ◽  
...  

Abstract This paper presents the use of pulsed laser stimulation with picosecond and femtosecond laser pulses. We first discuss the resolution improvement that can be expected when using ultrashort laser pulses. Two case studies are then presented to illustrate the possibilities of the pulsed laser photoelectric stimulation in picosecond single-photon and femtosecond two-photon modes.


Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 930
Author(s):  
Xiaoying Huang ◽  
Rongbin Su ◽  
Jiawei Yang ◽  
Mujie Rao ◽  
Jin Liu ◽  
...  

In this work, we successfully achieved wafer-scale low density InAs/GaAs quantum dots (QDs) for single photon emitter on three-inch wafer by precisely controlling the growth parameters. The highly uniform InAs/GaAs QDs show low density of μ0.96/μm2 within the radius of 2 cm. When embedding into a circular Bragg grating cavity on highly efficient broadband reflector (CBR-HBR), the single QDs show excellent optoelectronic properties with the linewidth of 3± 0.08 GHz, the second-order correlation factor g2(τ)=0.0322 ±0.0023, and an exciton life time of 323 ps under two-photon resonant excitation.


2008 ◽  
Vol 8 (11) ◽  
pp. 5854-5857 ◽  
Author(s):  
Guangping Zhu ◽  
Chunxiang Xu ◽  
Jing Zhu ◽  
Changgui Lu ◽  
Yiping Cui ◽  
...  

High density zinc oxide nanorods with uniform size were synthesized on (100) silicon substrate by vapor-phase transport method. The scanning electron microscopy images reveal that the nanorods have an average diameter of about 400 nm. The X-ray diffraction pattern demonstrates the wurtzite crystalline structure of the ZnO nanorods growing along [0001] direction. The single-photon excited photoluminescence presents a strong ultraviolet emission band at 394 nm and a weak visible emission band at 600 nm. When the ZnO nanorods were respectively pumped by various wavelength lasers from 520 nm to 700 nm, two-photon excited ultraviolet photoluminescence was observed. The dependence of the two-photon excited photoluminescence intensity on the excitation wavelength and power was investigated in detail.


2014 ◽  
Vol 8 (5) ◽  
pp. L76-L80 ◽  
Author(s):  
Andreas Eckstein ◽  
Guillaume Boucher ◽  
Aristide Lemaître ◽  
Pascal Filloux ◽  
Ivan Favero ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document