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Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
Published on: May 30, 2014
Coherent properties of a two-level system based on a quantum-dot photodiode
A Zrenner1, E Beham, S Stufler
1Walter Schottky Institut, Technische Universität München, Am Coulombwall, D-85748 Garching, Germany. zrenner@physik.upb.de
Nature
|August 9, 2002
Summary
Researchers developed a quantum dot device that converts light pulses into electrical signals. This breakthrough enables a single electron turnstile, advancing quantum information technology hardware.
Area of Science:
- Quantum Information Science
- Semiconductor Physics
- Optoelectronics
Background:
- Current information technology relies on incoherent processes in semiconductor devices.
- Future quantum information technologies require coherent phenomena and novel hardware.
- Semiconductor quantum dots are promising building blocks for quantum information processing.
Purpose of the Study:
- To demonstrate the conversion of coherent optical excitations in quantum dots into deterministic photocurrents.
- To integrate a quantum dot into an electrical circuit for quantum information applications.
- To show that a quantum dot device can function as an optically triggered single-electron turnstile.
Main Methods:
- Placing an Indium Gallium Arsenide (InGaAs) quantum dot within a photodiode structure.
- Applying electromagnetic fields to achieve coherent manipulation of excitonic energy levels (Rabi oscillations).
- Utilizing optical pi-pulses to completely invert the quantum dot's two-level system.
Main Results:
- Demonstrated the conversion of coherent optical excitations into deterministic photocurrents.
- Observed a current (I) directly proportional to the experimental repetition frequency (f) and elementary charge (e) (I = fe) for pi-pulse excitation.
- Confirmed the device's functionality as an optically triggered single-electron turnstile.
Conclusions:
- Coherent optical excitations in quantum dots can be reliably converted into electrical signals.
- The developed photodiode device serves as a functional single-electron turnstile.
- This work provides a crucial hardware component for future quantum information technologies.
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