A reversed Kerr travelling wave parametric amplifier: from near quantum-noise-limited amplificationto microwave photonics
le mardi 18 mai 2021 à 14h00
Séminaire nano-électronique quantique
Personne à contacter :
Conférence Zoom : consulter le lien de connexion dans les emails d'annonce ou contacter l'organisateur
Résumé : Travelling wave parametric amplifiers (TWPAs) recently became crucial tools in superconducting quantum technologies since they allow broadband and near quantum-noise-limited microwave detection. The main obstacle in developing TWPAs is the attainment of the phase matching condition between thepump field, which provides the energy for the amplification, and the signal field, to be amplified. I will present a new experimental approach to solving the phase matching problem by exploiting a Josephson metamaterial with in-situ tunability and sign reversal of the Kerr nonlinearity: reversed Kerr phase matching. Such novel reversed Kerr TWPA (1), composed of a chain of asymmetric Josephson junction-based inductive elements, shows amplification performance superior to the ones of previous state of the art TWPAs. In this talk, I will present the design, fabrication, and amplification characterization focusing on the novel reversed Kerr phase matching method. In addition, I will show recent experimental results on the generation of two-mode squeezed statesand discuss the exciting perspective of using such a device as a source of multimode entangled states in microwave photonics.
(1) Ranadive et al.A reversed Kerr traveling wave parametric amplifier(2021)http://arxiv.org/abs/2101.05815
2D-0D heterostructures devices : why ? how ? what ?
le mardi 25 mai 2021 à 14h00
Séminaire nano-électronique quantique
Personne à contacter :
Lieu :
Résumé : Because of their atomically-thin structure, high surface to volume ratio, and reduced electric screening, new properties and functionalities are expected to emerge when exploiting the interactions of two dimensional (‘2D’) materials placed in contact with other nanomaterials such as zero dimensional (‘0D’) systems including clusters, nanocrystals and molecules. These so-called Mixed-dimensional van der Waals Heterostructures are now at the forefront of basic nanoscience and applied nanotechnology, providing new sets of possibilities to tailor device functions and novel physical properties.[1]
Today, I will present some of our recent achievements and on-going works illustrating the possibilities offered by 2D-0D heterostructures in various fields of nanoelectronics including single-electron electronics [2], molecular electronics[3] and optoelectronics[4]. These 0D-2D devices take advantage of the functionalities of the 0D systems (electronic, magnetic, optic…) and of the specific properties of 2D materials such as : i) van der Waals interface, ii) high diffusion of metals enabling self-ordered growth of nanoclusters, iii) dual electric behavior combining in-plane charge transport with out-of-plane electric field transparency (they are thinner than the Debye screening length), iv) exacerbated surface/interface sensitivity. The works selected for this talk will allow me to introduce some of these concepts.
References : [1] D. Jariwala et al., Nat. Mater. 2017, 16, 170 ; [2] Mouafo et al, Adv. Mater. 2018, 30, 1802478; Mouafo et al., Adv.Func.Mat. 2021, 31, 2008255 ; Godel et al., Adv. Mater. 2017, 29, 1604837; [3] Noumbe et al., ACS Nano 2020, 14, 4567 ; [4] Konstantinov, J. Mat. Chem. C. 2021, 9, 2712.
