8 research outputs found
A hybrid (Al)GaAs-LiNbO3 surface acoustic wave resonator for cavity quantum dot optomechanics
A hybrid device comprising a (Al)GaAs quantum dot heterostructure and a
LiNbO surface acoustic wave resonator is fabricated by heterointegration.
High acoustic quality factors are demonstrated for an operation
frequency MHz. The measured large quality factor-frequency
products ensures the suppression of decoherence due to
thermal noise for temperatures exceeding . Frequency and
position dependent optomechanical coupling of single quantum dots and the
resonator modes is observed.Comment: Accepted manuscrip
Heterogeneous integration of superconducting thin films and epitaxial semiconductor heterostructures with lithium niobate
We report on scalable heterointegration of superconducting electrodes and epitaxial semiconductor quantum dots (QDs) on strong piezoelectric and optically nonlinear lithium niobate. The implemented processes combine the sputter-deposited thin film superconductor niobium nitride and III–V compound semiconductor membranes onto the host substrate. The superconducting thin film is employed as a zero-resistivity electrode material for a surface acoustic wave resonator with internal quality factors approx Q≈17,000 representing a three-fold enhancement compared to identical devices with normal conducting electrodes. Superconducting operation of ≈400MHz resonators is achieved to temperatures T>7K and electrical radio frequency powers Prf>+9dBm. Heterogeneously integrated single QDs couple to the resonant phononic field of the surface acoustic wave resonator operated in the superconducting regime. Position and frequency selective coupling mediated by deformation potential coupling is validated using time-integrated and time-resolved optical spectroscopy. Furthermore, acoustoelectric charge state control is achieved in a modified device geometry harnessing large piezoelectric fields inside the resonator. The hybrid QD—surface acoustic wave resonator can be scaled to higher operation frequencies and smaller mode volumes for quantum phase modulation and transduction between photons and phonons via the QD. Finally, the employed materials allow for the realization of other types of optoelectronic devices, including superconducting single photon detectors and integrated photonic and phononic circuits
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On-chip generation and dynamic piezo-optomechanical rotation of single photons
Integrated photonic circuits are key components for photonic quantum technologies and for the implementation of chip-based quantum devices. Future applications demand flexible architectures to overcome common limitations of many current devices, for instance the lack of tuneabilty or built-in quantum light sources. Here, we report on a dynamically reconfigurable integrated photonic circuit comprising integrated quantum dots (QDs), a Mach-Zehnder interferometer (MZI) and surface acoustic wave (SAW) transducers directly fabricated on a monolithic semiconductor platform. We demonstrate on-chip single photon generation by the QD and its sub-nanosecond dynamic on-chip control. Two independently applied SAWs piezo-optomechanically rotate the single photon in the MZI or spectrally modulate the QD emission wavelength. In the MZI, SAWs imprint a time-dependent optical phase and modulate the qubit rotation to the output superposition state. This enables dynamic single photon routing with frequencies exceeding one gigahertz. Finally, the combination of the dynamic single photon control and spectral tuning of the QD realizes wavelength multiplexing of the input photon state and demultiplexing it at the output. Our approach is scalable to multi-component integrated quantum photonic circuits and is compatible with hybrid photonic architectures and other key components for instance photonic resonators or on-chip detectors
On-chip generation and dynamic piezo-optomechanical rotation of single photons
Integrated photonic circuits are key components for photonic quantum
technologies and for the implementation of chip-based quantum devices. Future
applications demand flexible architectures to overcome common limitations of
many current devices, for instance the lack of tuneabilty or built-in quantum
light sources. Here, we report on a dynamically reconfigurable integrated
photonic circuit comprising integrated quantum dots (QDs), a Mach-Zehnder
interferometer (MZI) and surface acoustic wave (SAW) transducers directly
fabricated on a monolithic semiconductor platform. We demonstrate on-chip
single photon generation by the QD and its sub-nanosecond dynamic on-chip
control. Two independently applied SAWs piezo-optomechanically rotate the
single photon in the MZI or spectrally modulate the QD emission wavelength. In
the MZI, SAWs imprint a time-dependent optical phase and modulate the qubit
rotation to the output superposition state. This enables dynamic single photon
routing with frequencies exceeding one gigahertz. Finally, the combination of
the dynamic single photon control and spectral tuning of the QD realizes
wavelength multiplexing of the input photon state and demultiplexing it at the
output. Our approach is scalable to multi-component integrated quantum photonic
circuits and is compatible with hybrid photonic architectures and other key
components for instance photonic resonators or on-chip detectors
Multi-harmonic quantum dot optomechanics in fused LiNbO3–(Al)GaAs hybrids
We fabricated an acousto-optic semiconductor hybrid device for strong
optomechanical coupling of individual quantum emitters and a surface acoustic
wave. Our device comprises a surface acoustic wave chip made from highly
piezoelectric LiNbO and a GaAs-based semiconductor membrane with an
embedded layer of quantum dots. Employing multi-harmonic transducers, we
generated sound waves on LiNbO over a wide range of radio frequencies. We
monitored their coupling to and propagation across the semiconductor membrane
both in the electrical and optical domain. We demonstrate enhanced
optomechanical tuning of the embedded quantum dots with increasing frequencies.
This effect was verified by finite element modelling of our device geometry and
attributed to an increased localization of the acoustic field within the
semiconductor membrane. For moderately high acoustic frequencies, our
simulations predict strong optomechanical coupling making our hybrid device
ideally suited for applications in semiconductor based quantum acoustics.Comment: revised manuscript. unit conversion error fixe
Annealing effects on the magnetic properties of highly-packed vertically-aligned nickel nanotubes
Hysteresis loops showing the decrease of the saturation magnetic moment (left) through a dense array of vertically-aligned Ni nanotubes after their progressive thermal conversion into hybrid ferromagnetic/antiferromagnetic Ni/NiO nanotubes (right).</p
Quantum dot optomechanics in suspended nanophononic strings
The optomechanical coupling of quantum dots and flexural mechanical modes is
studied in suspended nanophononic strings. The investigated devices are
designed and monolithically fabricated on an (Al)GaAs heterostructure. Radio
frequency elastic waves with frequencies ranging between =250 MHz to 400 MHz
are generated as Rayleigh surface acoustic waves on the unpatterned substrate
and injected as Lamb waves in the nanophononic string. Quantum dots inside the
nanophononic string exhibit a 15-fold enhanced optomechanical modulation
compared to those dynamically strained by the Rayleigh surface acoustic wave.
Detailed finite element simulations of the phononic mode spectrum of the
nanophononic string confirm, that the observed modulation arises from valence
band deformation potential coupling via shear strain. The corresponding
optomechanical coupling parameter is quantified to .
This value exceeds that reported for vibrating nanorods by approximately one
order of magnitude at 100 times higher frequencies. Using this value, a derive
vertical displacements in the range of 10 nm is deduced from the experimentally
observed modulation. The results represent an important step towards the
creation of large scale optomechanical circuits interfacing single optically
active quantum dots with optical and mechanical waves.Comment: Submitted manuscrip