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We report a comprehensive Raman study of the phonon behaviour in PdSe$_2$ in the temperature range of 5 K to 300 K. A remarkable change in the Raman spectrum is observed at 120 K: a significant enhancement of the out-of-plane phonon…

We derive an analytical form of the Schmidt modes of spontaneous parametric down-conversion (SPDC) biphotons in both Cartesian and polar coordinates. We show that these correspond to Hermite-Gauss (HG) or Laguerre-Gauss (LG) modes only for…

Quantum Physics · Physics 2012-08-02 Filippo M. Miatto , Thomas Brougham , Alison M. Yao

We measure the transverse entanglement of photon pairs on their propagation from the near to the far field of spontaneous parametric downconversion (SPDC). The Fedorov ratio, depending on the widths of conditional and unconditional…

Quantum Physics · Physics 2015-06-12 Felix Just , Andrea Cavanna , Maria V. Chekhova , Gerd Leuchs

In this paper, we theoretically study spectral and temporal properties of pulsed spontaneous parametric down-conversion (SPDC) generated in lossy waveguides. Our theoretical approach is based on the formalism of Gaussian states and the…

We report new results regarding a source of polarization entangled photon-pairs created by the process of spontaneous parametric downconversion in two orthogonally oriented, periodically poled, bulk KTiOPO4 crystals (PPKTP). The source…

Quantum Physics · Physics 2009-11-11 Daniel Ljunggren , Maria Tengner , Philip Marsden , Matthew Pelton

Violet phosphorus (VP) has garnered attention for its appealing physical properties and potential applications in optoelectronics. We present a comprehensive investigation of the photo-degradation and thermal effects of exfoliated VP on…

We characterize a periodically poled KTP crystal that produces an entangled, two-mode, squeezed state with orthogonal polarizations, nearly identical, factorizable frequency modes, and few photons in unwanted frequency modes. We focus the…

The process of spontaneous parametric down-conversion (SPDC) in nonlinear crystals makes it fairly easy to generate entangled photon states. It has been known for some time that the conversion efficiency can be improved by employing…

Quantum Physics · Physics 2017-08-23 Jonas Soderholm , Keiichi Hirano , Shigehiko Mori , Shuichiro Inoue , Sunao Kurimura

Broadband quantum light is a vital resource for quantum metrology and spectroscopy applications such as quantum optical coherence tomography or entangled two photon absorption. For entangled two photon absorption in particular, very high…

We present femtosecond time-resolved pump-probe spectroscopic studies of a pseudogap (PG) along with the superconducting (SC) gap in an overdoped iron pnictide Ca(Fe0.927Co0.073)2As2. It is seen that the temperature evolution of the…

Superconductivity · Physics 2014-03-12 Sunil Kumar , L. Harnagea , S. Wurmehl , B. Buechner , A. K. Sood

The femtosecond optical pump-probe technique was used to study dynamics of photoexcited electrons and coherent optical phonons in transition metals Zn and Cd as a function of temperature and excitation level. The optical response in time…

Strongly Correlated Electrons · Physics 2009-11-11 Muneaki Hase , Kunie Ishioka , Jure Demsar , Kiminori Ushida , Masahiro Kitajima

We present an integrated source of polarization entangled photon pairs in the telecom regime, which is based on type II-phasematched parametric down-conversion (PDC) in a Ti-indiffused waveguide in periodically poled lithium niobate. The…

Quantum Physics · Physics 2015-06-16 Harald Herrmann , Xu Yang , Abu Thomas , Andreas Poppe , Wolfgang Sohler , Christine Silberhorn

Spontaneous parametric down conversion (SPDC), especially in non-linear waveguides, serves as an important process to generate quantum states of light with desired properties. In this work, we report on a design of a strongly dispersive,…

Applied Physics · Physics 2024-11-28 Muskan Arora , Jyoti Arya , Pranav Chokkara , Jasleen Lugani

We propose a method for directly producing radially and azimuthally polarized photon pairs through spontaneous parametric downconversion (SPDC). This method constitutes a novel geometry for SPDC, in which a radially polarized Bessel-Gauss…

Quantum Physics · Physics 2016-10-14 Rebecca Y. Saaltink , Lambert Giner , Robert W. Boyd , Ebrahim Karimi , Jeff S. Lundeen

Entangled photon sources (EPSs) are essential building blocks for scalable quantum communication and quantum key distribution (QKD). We present a stable, highly nondegenerate EPS based on type-0 spontaneous parametric down-conversion (SPDC)…

We experimentally demonstrate a source of polarization entangled photon-pairs based on a single periodically-poled potassium titanyl phosphate (PPKTP) crystal pumped with a broadband, free running laser diode.The crystal is placed within a…

Quantum Physics · Physics 2020-01-29 Alexander Lohrmann , Chithrabhanu Perumangatt , Aitor Villar , Alexander Ling

We demonstrate sub-shot-noise photon-number correlations in a (temporal) multimode mesoscopic ($\sim 10^3$ detected photons) twin-beam produced by ps-pulsed spontaneous non-degenerate parametric downconversion. We have separately detected…

Quantum Physics · Physics 2009-11-13 Maria Bondani , Alessia Allevi , Guido Zambra , Matteo G. A. Paris , Alessandra Andreoni

Chip-integrated photon-pair sources based on spontaneous parametric down-conversion (SPDC) have emerged as a promising solution for scalable quantum light generation. Thin-film lithium tantalate (TFLT) is a compelling $\chi^{(2)}$ platform,…

Optics · Physics 2026-05-26 Sakthi Sanjeev Mohanraj , Xiaodong Shi , Ran Yang , Lin Zhou , Di Zhu

Hyperentangled photonic states - exhibiting nonclassical correlations in several degrees of freedom - offer improved performance of quantum optical communication and computation schemes. Experimentally, a hyperentanglement of…

Quantum Physics · Physics 2021-06-21 Michał Lipka , Michał Parniak

Tamm plasmon-polaritons (TPPs) - optical modes localized at the interface between a metal and a photonic crystal (PhC) - offer a versatile platform for confining light in planar optoelectronic devices. However, their implementation in…

Optics · Physics 2026-05-20 Yurii V. Konov , Rashid G. Bikbaev , Feng Wu , Ivan V. Timofeev