Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Science

Controlled Phase Shifts with a Single Quantum Dot

Ilya Fushman, Dirk Englund, Andrei Faraon, Nick Stoltz, Pierre M. Petroff, Jelena Vuckovic A

Published May 8, 2008• 442 citations
Publisher

Abstract

Optical nonlinearities enable photon-photon interaction and lie at the heart of several proposals for quantum information processing, quantum nondemolition measurements of photons, and optical signal processing. To date, the largest nonlinearities have been realized with single atoms and atomic ensembles. We show that a single quantum dot coupled to a photonic crystal nanocavity can facilitate controlled phase and amplitude modulation between two modes of light at the single-photon level. At larger control powers, we observed phase shifts up to pi/4 and amplitude modulation up to 50%. This was accomplished by varying the photon number in the control beam at a wavelength that was the same as that of the signal, or at a wavelength that was detuned by several quantum dot linewidths from the signal. Our results present a step toward quantum logic devices and quantum nondemolition measurements on a chip.

DOI
10.1126/science.1154643

Related papers

Single photon nonlinear optics in photonic crystals

Dirk Englund, Ilya Fushman, Andrei Faraon +1 more

We coherently probe a quantum dot that is strongly coupled to a photonic crystal nano-cavity by scattering of a resonant laser beam. The coupled system's response is highly nonlinear as the quantum dot saturates with nearly one photon per cavity lifetime. This system enables large amplitude and phase shifts of a signal beam via a control beam, both at single photon levels. We demonstrate photon-photon interactions with short pulses in a system that is promising for ultra-low power switches and two-qubit quantum gates.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jan 26, 2009•0 citations

Direct observation of a few-photon phase shift induced by a single quantum emitter in a waveguide

Mathias Staunstrup, Alexey Tiranov, Ying Wang +7 more

Realizing a sensitive photon-number-dependent phase shift on a light beam is required both in classical and quantum photonics. It may lead to new applications for classical and quantum photonics machine learning or pave the way for realizing photon-photon gate operations. Nonlinear phase-shifts require efficient light-matter interaction, and recently quantum dots coupled to nanophotonic devices have enabled near-deterministic single-photon coupling. We experimentally realize an optical phase shift of 0.19π ± 0.03 radians ( ≈ 34 degrees) using a weak coherent state interacting with a single quantum dot in a planar nanophotonic waveguide. The phase shift is probed by interferometric measurements of the light scattered from the quantum dot in the waveguide. The process is nonlinear in power, the saturation at the single-photon level and compatible with scalable photonic integrated circuitry. The work may open new prospects for realizing high-efficiency optical switching or be applied for proof-of-concept quantum machine learning or quantum simulation demonstrations.

Nature Communications•Aug 31, 2024•14 citations

Nonlinear optics near the single photon level with quantum dots coupled to photonic crystals

Edo Waks A, Deepak Sridharan, Ranojoy Bose +3 more

Low power optical nonlinearities are a crucial requirement for data routing and next generation all-optical processing. The majority of nonlinear optical devices to date exploit weak nonlinearities from a large ensemble of atomic systems, resulting in both high power dissipation and a large device footprint. Quantum dots (QDs) coupled to photonic crystals can provide significant reduction in both device size and power dissipation. The interaction between these two systems creates extremely strong light-matter interaction owing to the tight optical confinement of photonic crystals and large oscillator strengths of QDs. Such interactions enable optical nonlinearities near the single photon level. In this work we investigate the nonlinear properties of QDs coupled to photonic crystals. We demonstrate large optical Stark shift with only 10 photons. We then propose and demonstrate a novel photonic circuit that can route light on a chip with extremely low optical powers.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Aug 19, 2011•0 citations

Photon Phase Shift at the Few-Photon Level and Optical Switching by a Quantum Dot in a Microcavity

L.M. Wells, Sokratis Kalliakos, B. Villa +6 more

Quantum-dot-based nonlinearities are an important building block for logic operations in quantum information processing. The authors build on theoretical proposals by using the nonlinear effects of a spin-photon interaction and measuring the resultant phase shifts of scattered light pulses induced by a semiconductor quantum dot. Phase rotations of almost 80\ifmmode^\circ\else\textdegree\fi{} are achieved at the single-photon level, and phase switching is demonstrated. These findings highlight the importance of semiconductor quantum dots as a nonlinear medium for developing quantum information processing and quantum photonic integrated circuits.

arXiv:1907.07991•Physical Review Applied•Jun 6, 2019•19 citations

Direct observation of non-linear optical phase shift induced by a single quantum emitter in a waveguide

Mathias Staunstrup, Alexey Tiranov, Ying Wang +7 more

Realizing a sensitive photon-number-dependent phase shift on a light beam is required both in classical and quantum photonics. It may lead to new applications for classical and quantum photonics machine learning or pave the way for realizing photon-photon gate operations. Non-linear phase-shifts require efficient light-matter interaction, and recently quantum dots coupled to nanophotonic devices have enabled near-deterministic single-photon coupling. We experimentally realize an optical phase shift of $0.19 π\pm 0.03$ radians ($\approx 34$ degrees) using a weak coherent state interacting with a single quantum dot in a planar nanophotonic waveguide. The phase shift is probed by interferometric measurements of the light scattered from the quantum dot in the waveguide. The nonlinear process is sensitive at the single-photon level and can be made compatible with scalable photonic integrated circuitry. The work may open new prospects for realizing high-efficiency optical switching or be applied for proof-of-concept quantum machine learning or quantum simulation demonstrations.

arXiv:2305.06839•May 11, 2023•1 citation

Single photon nonlinear optics on photonic crystal chips

Dirk Englund

A single semiconductor quantum dot that is strongly coupled to a photonic crystal nanocavity yields optical nonlinearities at the single photon level. The promise of quantum information processing is driving developments in several different physical implementations. Photons are attractive as carriers of quantum information be-cause they can travel long distances without losing their infor-mation through interactions with their environment. However, their passive nature can be a problem in applications such as the construction of logic gates, where it is necessary for two or more photons to interact. This interaction requires a nonlinear optical medium. Particularly strong nonlinearities are achieved when photons drive an emitter near its resonance frequency, and this nonlinearity is even greater if the photon is confined near the emitter in an optical cavity.

SPIE Newsroom•Jan 1, 2009•0 citations
Optical nonlinearities enable photon-photon interaction and lie at the heart of several proposals for quantum information processing, quantum nondemolition measurements of photons, and optical signal processing. To date, the largest nonlinearities have been realized with single atoms and atomic ensembles. We show that a single quantum dot coupled to a photonic crystal nanocavity can facilitate controlled phase and amplitude modulation between two modes of light at the single-photon level. At larger control powers, we observed phase shifts up to pi/4 and amplitude modulation up to 50%. This was accomplished by varying the photon number in the control beam at a wavelength that was the same as that of the signal, or at a wavelength that was detuned by several quantum dot linewidths from the signal. Our results present a step toward quantum logic devices and quantum nondemolition measurements on a chip.
We coherently probe a quantum dot that is strongly coupled to a photonic crystal nano-cavity by scattering of a resonant laser beam. The coupled system's response is highly nonlinear as the quantum dot saturates with nearly one photon per cavity lifetime. This system enables large amplitude and phase shifts of a signal beam via a control beam, both at single photon levels. We demonstrate photon-photon interactions with short pulses in a system that is promising for ultra-low power switches and two-qubit quantum gates.
Realizing a sensitive photon-number-dependent phase shift on a light beam is required both in classical and quantum photonics. It may lead to new applications for classical and quantum photonics machine learning or pave the way for realizing photon-photon gate operations. Nonlinear phase-shifts require efficient light-matter interaction, and recently quantum dots coupled to nanophotonic devices have enabled near-deterministic single-photon coupling. We experimentally realize an optical phase shift of 0.19π ± 0.03 radians ( ≈ 34 degrees) using a weak coherent state interacting with a single quantum dot in a planar nanophotonic waveguide. The phase shift is probed by interferometric measurements of the light scattered from the quantum dot in the waveguide. The process is nonlinear in power, the saturation at the single-photon level and compatible with scalable photonic integrated circuitry. The work may open new prospects for realizing high-efficiency optical switching or be applied for proof-of-concept quantum machine learning or quantum simulation demonstrations.
Low power optical nonlinearities are a crucial requirement for data routing and next generation all-optical processing. The majority of nonlinear optical devices to date exploit weak nonlinearities from a large ensemble of atomic systems, resulting in both high power dissipation and a large device footprint. Quantum dots (QDs) coupled to photonic crystals can provide significant reduction in both device size and power dissipation. The interaction between these two systems creates extremely strong light-matter interaction owing to the tight optical confinement of photonic crystals and large oscillator strengths of QDs. Such interactions enable optical nonlinearities near the single photon level. In this work we investigate the nonlinear properties of QDs coupled to photonic crystals. We demonstrate large optical Stark shift with only 10 photons. We then propose and demonstrate a novel photonic circuit that can route light on a chip with extremely low optical powers.
Quantum-dot-based nonlinearities are an important building block for logic operations in quantum information processing. The authors build on theoretical proposals by using the nonlinear effects of a spin-photon interaction and measuring the resultant phase shifts of scattered light pulses induced by a semiconductor quantum dot. Phase rotations of almost 80\ifmmode^\circ\else\textdegree\fi{} are achieved at the single-photon level, and phase switching is demonstrated. These findings highlight the importance of semiconductor quantum dots as a nonlinear medium for developing quantum information processing and quantum photonic integrated circuits.
Realizing a sensitive photon-number-dependent phase shift on a light beam is required both in classical and quantum photonics. It may lead to new applications for classical and quantum photonics machine learning or pave the way for realizing photon-photon gate operations. Non-linear phase-shifts require efficient light-matter interaction, and recently quantum dots coupled to nanophotonic devices have enabled near-deterministic single-photon coupling. We experimentally realize an optical phase shift of 0.19π±0.030.19 π\pm 0.030.19π±0.03 radians (≈34\approx 34≈34 degrees) using a weak coherent state interacting with a single quantum dot in a planar nanophotonic waveguide. The phase shift is probed by interferometric measurements of the light scattered from the quantum dot in the waveguide. The nonlinear process is sensitive at the single-photon level and can be made compatible with scalable photonic integrated circuitry. The work may open new prospects for realizing high-efficiency optical switching or be applied for proof-of-concept quantum machine learning or quantum simulation demonstrations.
A single semiconductor quantum dot that is strongly coupled to a photonic crystal nanocavity yields optical nonlinearities at the single photon level. The promise of quantum information processing is driving developments in several different physical implementations. Photons are attractive as carriers of quantum information be-cause they can travel long distances without losing their infor-mation through interactions with their environment. However, their passive nature can be a problem in applications such as the construction of logic gates, where it is necessary for two or more photons to interact. This interaction requires a nonlinear optical medium. Particularly strong nonlinearities are achieved when photons drive an emitter near its resonance frequency, and this nonlinearity is even greater if the photon is confined near the emitter in an optical cavity.