scholarly journals Spontaneous parametric down-conversion in chirped, aperiodically-poled crystals

2015 ◽  
Vol 13 (05) ◽  
pp. 1550032 ◽  
Author(s):  
X. Sánchez-Lozano ◽  
J. L. Lucio M.
Keyword(s):  
Single Photon ◽  
Nonlinear Crystal ◽  
Spectral Amplitude ◽  
Single Photons ◽  
Ppln Crystal ◽  
Temporal Properties ◽  
Photon Pairs ◽  
Spectral Components ◽  
Parametric Down Conversion ◽  
Down Conversion

We present a theoretical analysis of the process of spontaneous parametric down conversion (SPDC) in a nonlinear crystal characterized by a linearly-chirped χ(2) grating along the direction of propagation. Our analysis leads to an expression for the joint spectral amplitude, based on which we can derive various spectral–temporal properties of the photon pairs and of the heralded single photons obtained from the photon pairs, including: The single-photon spectrum (SPS), the chronocyclic Wigner function (CWF) and the Schmidt number. The simulations that we present are for the specific case of a collinear SPDC source based on a PPLN crystal with the signal and idler photons emitted close to the telecom window. We discuss the mechanism for spectral broadening due to the presence of a linearly chirped χ(2) grating, showing that not only the width but also to some extent the shape of the SPDC spectrum may be controlled. Also, we discuss how the fact that the different spectral components are emitted on different planes in the crystal leads to single-photon chirp.

scholarly journals Background and Review of Cavity-Enhanced Spontaneous Parametric Down-Conversion

2019 ◽  
Vol 124 ◽  
Author(s):  
Oliver Slattery ◽  
Lijun Ma ◽  
Kevin Zong ◽  
Xiao Tang
Keyword(s):  
Single Photon ◽  
Nonlinear Crystal ◽  
Transition Frequency ◽  
Atomic Ensemble ◽  
Atomic Ensembles ◽  
Quantum Communications ◽  
Resonant Modes ◽  
Spectral Linewidth ◽  
Parametric Down Conversion ◽  
Down Conversion

Spontaneous parametric down-conversion (SPDC) in a nonlinear crystal has been a workhorse for the generation of entangled and correlated single-photon pairs used for quantum communications applications for nearly three decades. However, as a naturally broadband process, the ability of SPDC to interface with the very narrow energy transitions in atomic ensembles for implementing quantum memories, which are needed for quantum repeaters to extend the reach of quantum communications, was initially limited. To overcome this limitation, the process was enhanced by placing the nonlinear crystal inside a resonating cavity. This modified process has some important advantages, including narrowing the spectral linewidth of generated photons into brighter resonant modes of the cavity, and the ability to lock the desired mode of the cavity to the targeted transition frequency of the atomic ensemble. This paper presents an overview of the principle of cavity-enhanced SPDC, a review of works to date using this technique, and an example of one of these implementations.

scholarly journals Broadband infrared light source by simultaneous parametric down-conversion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Masayuki Hojo ◽  
Koichiro Tanaka
Keyword(s):  
Light Source ◽  
Gas Sensing ◽  
Nonlinear Crystal ◽  
Matching Condition ◽  
Infrared Region ◽  
Infrared Light ◽  
Photon Pairs ◽  
Parametric Down Conversion ◽  
Phase Matching Condition ◽  
Down Conversion

AbstractSpontaneous parametric down-conversion is an essential tool for a quantum light source in the infrared region ranging 2–5 µm for the purpose of material identification, chemical analysis, and gas sensing. So far, photon pairs from the process in a nonlinear crystal have low tunability and a narrow spectral range because of the phase-matching condition. Here, we propose a novel type of spontaneous parametric down-conversion processes that overcomes these challenges, where two photon pairs are simultaneously produced in the visible and infrared regions in periodically poled stoichiometric lithium tantalite. It allows broadband and tunable generation of infrared photon pairs that can be employed as an alternative light source for quantum infrared spectroscopy.

scholarly journals Observation of frequency-uncorrelated photon pairs generated by counter-propagating spontaneous parametric down-conversion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi-Chen Liu ◽  
Dong-Jie Guo ◽  
Kun-Qian Ren ◽  
Ran Yang ◽  
Minghao Shang ◽  
...  
Keyword(s):  
Single Photon ◽  
Difference Frequency Generation ◽  
Matching Condition ◽  
Experimental Result ◽  
Pump Light ◽  
Generation Process ◽  
Schmidt Decomposition ◽  
Photon Pairs ◽  
Parametric Down Conversion ◽  
Down Conversion

AbstractWe report the generation of frequency-uncorrelated photon pairs from counter-propagating spontaneous parametric down-conversion in a periodically-poled KTP waveguide. The joint spectral intensity of photon pairs is characterized by measuring the corresponding stimulated process, namely, the difference frequency generation process. The experimental result shows a clear uncorrelated joint spectrum, where the backward-propagating photon has a narrow bandwidth of 7.46 GHz and the forward-propagating one has a bandwidth of 0.23 THz like the pump light. The heralded single-photon purity estimated through Schmidt decomposition is as high as 0.996, showing a perspective for ultra-purity and narrow-band single-photon generation. Such unique feature results from the backward-wave quasi-phase-matching condition and does not has a strict limitation on the material and working wavelength, thus fascinating its application in photonic quantum technologies.

scholarly journals Efficient Single-Photon Pair Generation by Spontaneous Parametric Down-Conversion in Nonlinear Plasmonic Metasurfaces

Nanoscale ◽  
2021 ◽  
Author(s):  
Boyuan Jin ◽  
Dhananjay Mishra ◽  
Christos Argyropoulos
Keyword(s):  
Nonlinear Optical ◽  
Single Photon ◽  
Photon Pair ◽  
Optical Techniques ◽  
Photon Pairs ◽  
Parametric Down Conversion ◽  
Pair Generation ◽  
Down Conversion

Spontaneous parametric down-conversion (SPDC) is one of the most versatile nonlinear optical techniques for the generation of entangled and correlated single-photon pairs. However, it suffers from very poor efficiency leading...

scholarly journals Spectral characterization of SPDC-based single-photon sources for quantum key distribution

2021 ◽  
Author(s):  
Sabine Euler ◽  
Erik Fitzke ◽  
Oleg Nikiforov ◽  
Daniel Hofmann ◽  
Till Dolejsky ◽  
...  
Keyword(s):  
Quantum Key Distribution ◽  
Single Photon ◽  
Complex Structure ◽  
Key Distribution ◽  
Spectral Characterization ◽  
Single Photons ◽  
Transverse Modes ◽  
Parametric Down Conversion ◽  
Photon Spectra ◽  
Down Conversion

AbstractIn our laboratory, we employ two biphoton sources for quantum key distribution. The first is based on cw parametric down-conversion of photons at 404 nm in PPKTP waveguide chips, while the second is based on the pulsed parametric down-conversion of 775 nm photons in PPLN waveguides. The spectral characterization is important for the determination of certain side-channel attacks. A Hong-Ou-Mandel experiment employing the first photon source revealed a complex structure of the common Hong-Ou-Mandel dip. By measuring the spectra of the single photons at 808 nm, we were able to associate these structures to the superposition of different transverse modes of the pump photons in our waveguide chips. The pulsed source was characterized by means of single-photon spectra measured by a sensitive spectrum analyzer as well as dispersion-based measurements. Finally, we also describe Hong-Ou-Mandel experiments using the photons from the second source.

scholarly journals Spectrally multiplexed and ultrabright entangled photon pairs in a lithium niobate microresonator

2021 ◽  
Author(s):  
Bo-Yu Xu ◽  
Li-Kun Chen ◽  
Jintian Lin ◽  
Lan-Tian Feng ◽  
Rui Niu ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Single Photon ◽  
Phase Matching ◽  
Quantum Networks ◽  
Broad Bandwidth ◽  
Photon Pairs ◽  
Parametric Down Conversion ◽  
Entangled Photon Pairs ◽  
On Chip ◽  
Down Conversion

Abstract On-chip bright quantum sources with multiplexing ability are extremely high in demand for the integrated quantum networks with unprecedented scalability and complexity. Here, we demonstrate an ultrabright and broadband biphoton quantum source generated in a lithium niobate microresonator system. Without introducing the conventional domain poling, the on-chip microdisk produces entangled photon pairs covering a broad bandwidth promised by natural phase matching in spontaneous parametric down conversion. Experimentally, the multiplexed photon pairs are characterized by 30 nm bandwidth limited by the filtering system, which can be furthered enlarged. Meanwhile, the generation rate reaches 5.13 MHz/μW with a coincidence-to- accidental ratio up to 804. Besides, the quantum source manifests the prominent purity with heralded single photon correlation g(2)H(0)=0.0098±0.0021 and energy-time entanglement with excellent interference visibility of 96.5%±1.9%.

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