Multiharmonic Frequency-Chirped Transducers for Surface-Acoustic-Wave Optomechanics
Sprache des Titels:
Englisch
Original Kurzfassung:
Wide-passband interdigital transducers are employed to establish a stable phase lock between a train of
laser pulses emitted by a mode-locked laser and a surface acoustic wave generated electrically by the
transducer. The transducer design is based on a multiharmonic split-finger architecture for the excitation of
a fundamental surface acoustic wave and a discrete number of its overtones. Simply by introducing a
variation of the transducer?s periodicity p, a frequency chirp is added. This combination results in wide
frequency bands for each harmonic. The transducer?s conversion efficiency from the electrical to the
acoustic domain is characterized optomechanically using single quantum dots acting as nanoscale pressure
sensors. The ability to generate surface acoustic waves over a wide band of frequencies enables advanced
acousto-optic spectroscopy using mode-locked lasers with fixed repetition rate. Stable phase locking
between the electrically generated acoustic wave and the train of laser pulses is confirmed by performing
stroboscopic spectroscopy on a single quantum dot at a frequency of 320 MHz. Finally, the dynamic
spectral modulation of the quantum dot is directly monitored in the time domain combining stable phaselocked
optical excitation and time-correlated single-photon counting. The demonstrated scheme will be
particularly useful for the experimental implementation of surface-acoustic-wave-driven quantum gates of
optically addressable qubits or collective quantum states or for multicomponent Fourier synthesis of
tailored nanomechanical waveforms.
Forschungs-