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Mode-locked laser for fast quantum state manipulation

English title Mode-locked laser for fast quantum state manipulation
Applicant Warburton Richard
Number 144979
Funding scheme R'EQUIP
Research institution Departement Physik Universität Basel
Institution of higher education University of Basel - BS
Main discipline Condensed Matter Physics
Start/End 01.01.2013 - 31.12.2013
Approved amount 120'000.00
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Keywords (5)

quantum dot; ultrafast; single photon; spin qubit; mode-locked laser

Lay Summary (German)

Lead
Mode-locked laser for fast quantum state manipulation
Lay summary

The coherent manipulation of quantum states is a key area in solid-state physics. It involves powerful concepts, many developed in atomic physics and quantum optics, to advanced solid-state materials, notably semiconductors and superconductors. A clear advantage of the solid-state is the possibility of on-chip integration for applications in quantum sensing, quantum communication and quantum information processing. The solid-state environment is complex, in particular the processes by which information encoded in a single quantum state leaks to the environment.

Single photons play a crucial role in quantum science and technology: they provide presently the only way of interfacing remote quantum systems. Remarkably, arguably the best emitter of single photons at present is a single quantum dot, a semiconductor-based solid-state system: a single quantum dot is a fast, robust, narrow linewidth, highly antibunched source of single photons, properties not shared by any other emitter.

The radiative lifetime of a semiconductor quantum dot is typically around 1 ns. This defines a crucial time-scale: coherent manipulation has to be carried out on sub-ns time-scales. Coherence can be extended to longer times using a spin qubit. In this case, sub-ns manipulation remains crucial as it allows many gate operations to be carried out before coherence is lost.

The goal here is to set up new experimental hardware for manipulating quantum states in semiconductors on sub-ns time-scales. The hardware will produce and monitor ps laser pulses with both a duration and chirp tailored to particular applications. The immediate applications are in quantum imaging, single photon generation and rotations of single spins.

Direct link to Lay Summary Last update: 18.12.2012

Responsible applicant and co-applicants

Collaboration

Group / person Country
Types of collaboration
Lehrstuhl für angewandte Festkörperphysik Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
IBM Switzerland (Europe)
- Research Infrastructure
Quantum Atom Optics Lab Treutlein Group/Department of Physics, University of Basel Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Nanostructures: Physics and Technology Talk given at a conference Deterministic Creation of a Biexciton in a Self-Assembled Quantum Dot 27.06.2016 St. Petersburg, Russia Warburton Richard;
International Conference on the Quantum Dots Poster Deterministic creation of a biexciton in a self-assembled quantum dot 22.05.2016 Jeju, Korean Republic (South Korea) Warburton Richard;
Solid State Quantum Photonics Talk given at a conference Deterministic Creation of a Biexciton in a Self-Assembled Quantum Dot 22.03.2016 Sheffield, Great Britain and Northern Ireland Warburton Richard;


Associated projects

Number Title Start Funding scheme
140311 Visitor program for Basel Center for Quantum Computing and Quantum Coherence ('QC2 Basel') 01.04.2012 Project funding (Div. I-III)
132313 Electro-optics of semiconductor nanostructures 01.04.2011 Project funding (Div. I-III)
175748 Electro-optics of semiconductor nanostructures 01.10.2017 Project funding (Div. I-III)
156637 Electro-optics of semiconductor nanostructures 01.10.2014 Project funding (Div. I-III)
132519 Entanglement on Atom Chips 01.10.2010 Project funding (Div. I-III)

Abstract

The coherent manipulation of quantum states is a key area in solid-state physics. It involves the application of powerful concepts, many developed originally in atomic physics and quantum optics, to advanced solid-state materials, notably semiconductors, superconductors and ultra-pure diamond. A clear advantage of the solid-state is the possibility of on-chip integration for applications in quantum sensing, quantum communication and possibly also quantum information processing. The solid-state environment is complex and in particular decoherence, the process by which information encoded in a single quantum state leaks to the environment, is a rich area, full of subtleties. Understanding and manipulating decoherence of a spin qubit in a semiconductor for instance has already led to a massive improvement in the decoherence time.Single photons play a crucial role in quantum science and technology: they provide presently the only known way of interfacing remote quantum systems. A quantum repeater for example operates by using single photons to entangle remote nodes and has the power to extend quantum cryptography, quantum communication using single photons, beyond the 100 km transmission barrier of optical fibres. Remarkably, arguably the best emitter of single photons at present is a single quantum dot, a semiconductor-based solid-state system: a single quantum dot is a fast, robust, narrow linewidth, highly antibunched source of single photons, properties not shared by any other emitter. The radiative lifetime of a semiconductor quantum dot is typically around 1 ns. This defines a crucial time-scale: coherent manipulation of this quasi-two-level-system has to be carried out on sub-ns time-scales. Coherence can be extended to longer times using a spin qubit for which the decoherence times are moving from the ns to the micro-second regime as a result of materials improvement and more sophisticated experimental techniques. Significantly however, sub-nano-second manipulation remains crucial as it allows many gate operations to be carried out before coherence is lost. It is proposed here to acquire new experimental hardware for manipulating quantum states in semiconductors on sub-ns time-scales. The hardware will produce and monitor ps laser pulses with both a duration and chirp tailored to particular applications. The main components are a widely-tunable, turn-key ultra-fast laser producing 100 fs pulses; a 4f spectrometer with spatial light modulators to produce ps designer pulses; and an autocorrelator to characterize the output. The immediate applications are (i) nanoscopic imaging of a quantum dot wave function; (ii) the generation of single photons at 780 nm for a semiconductor-cold atom quantum interface; (iii) rotations of ultra-fast single spins. Furthermore, the laser system will support all on-going activities, it will seed new projects, and it will enable the group to bid more competitively for third-party funding.
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