Abstract-Terahertz field control of interlayer transport modes in cuprate superconductors

Frank Schlawin, Anastasia S. D. Dietrich, Martin Kiffner, Andrea Cavalleri, and Dieter Jaksch

https://journals.aps.org/prb/abstract/10.1103/PhysRevB.96.064526

We theoretically show that terahertz pulses with controlled amplitude and frequency can be used to switch between stable transport modes in layered superconductors, modeled as stacks of Josephson junctions. We find pulse shapes that deterministically switch the transport mode between superconducting, resistive, and solitonic states. We develop a simple model that explains the switching mechanism as a destabilization of the center-of-mass excitation of the Josephson phase, made possible by the highly nonlinear nature of the light-matter coupling.

• 
• 
• 
• 
• 
• 
• 

Abstract-Terahertz field control of interlayer transport modes in cuprate superconductors

Frank Schlawin, Anastasia S. D. Dietrich, Martin Kiffner, Andrea Cavalleri, Dieter Jaksch

(Submitted on 24 Jul 2017)

https://128.84.21.199/abs/1707.07459

We theoretically show that terahertz pulses with controlled amplitude and frequency can be used to switch between stable transport modes in layered superconductors, modelled as stacks of Josephson junctions. We find pulse shapes that deterministically switch the transport mode between superconducting, resistive and solitonic states. We develop a simple model that explains the switching mechanism as a destablization of the centre of mass excitation of the Josephson phase, made possible by the highly non-linear nature of the light-matter coupling.

Abstract-Two-way conversion of microwave and terahertz radiation into optical fields in Rydberg gases

Martin Kiffner, Amir Feizpour, Krzysztof T. Kaczmarek, Dieter Jaksch, Joshua Nunn

(Submitted on 26 Jan 2016 (v1), last revised 26 May 2016 (this version, v2))

http://arxiv.org/abs/1601.07100

We show that cold Rydberg gases enable an efficient six-wave mixing process where microwave or terahertz fields are coherently converted into optical fields and vice versa. This process is made possible by the long lifetime of Rydberg states, the strong coupling of millimeter waves to Rydberg transitions and a quantum interference effect related to Electromagnetically Induced Transparency. We show that conversion efficiencies within an independent atom approach are of the order of 95% and analyse the impact of dipole-dipole interactions on our scheme. We find that effective conversion efficiencies in the presence of Rydberg-Rydberg interactions can still be as high as 85% based on an implementation with Rubidium atoms. Our frequency conversion scheme does not require cavities and can be implemented for a broad spectrum of terahertz and microwave fields due to the abundance of transitions within the Rydberg manifold.

Abstract-Parametric Amplification of a Terahertz Quantum Plasma Wave

Authors: Srivats Rajasekaran, Eliza Casandruc, Yannis Laplace, Daniele Nicoletti, Genda D. Gu,Stephen R. Clark, Dieter Jaksch, Andrea Cavalleri

http://www.mathpubs.com/detail/1511.08378v1/Parametric-Amplification-of-a-Terahertz-Quantum-Plasma-Wave

Many applications in photonics require all-optical manipulation of plasma waves, which can concentrate electromagnetic energy on sub-wavelength length scales. This is difficult in metallic plasmas because of their small optical nonlinearities. Some layered superconductors support weakly damped plasma waves, involving oscillatory tunneling of the superfluid between capacitively coupled planes. Such Josephson plasma waves (JPWs) are also highly nonlinear, and exhibit striking phenomena like cooperative emission of coherent terahertz radiation, superconductor-metal oscillations and soliton formation. We show here that terahertz JPWs in cuprate superconductors can be parametrically amplified through the cubic tunneling nonlinearity. Parametric amplification is sensitive to the relative phase between pump and seed waves and may be optimized to achieve squeezing of the order parameter phase fluctuations or single terahertz-photon devices.