List of members |
Facilities |
Internships and jobs |
PhD |
Publications |
News |
Team
- Permanent member: Paola Atkinson
In collaboration with the “Acoustics for nanoscience” team, we are fabricating GaAs/AlAs superlattice microcavities for optomechanical applications. The GaAs/AlAs material system is particularly attractive due to the fact that the difference in GaAs and AlAs refractive indices is similar to the difference in the speed of sound in the two materials. This means that a GaAs/AlAs microcavity structure can simultaneously provide confinement of light in the optical/near infrared range and confinement of phonons in the tens of GHz range as shown below. This simultaneous confinement results in a good overlap between optical and mechanical modes, and therefore very high optomechanical coupling rates, i.e. highly efficient generation of vibration modes by optical excitation, can be expected.
Légende 1: (a) Schematic of a GaAs/AlAs micropillar microcavity, (b) modelled squared displacement of the acoustic longitudinal mode, |u|² and of the electric field of the optical mode, |E|² of a 5 µm diameter pillar with 5 pairs per mirror [2] (c) SEM image of a 16µm diameter micropillar cavity with 20 pairs per mirror, (d) measured amplitude (points) and fit (curve) of the fundamental acoustic mode of the 16 µm diameter pillar, f m (16 GHz) and its odd harmonics 3 f m , 5 f m , and 7 f m as the pump laser repetition frequency is scanned through a integer fraction of the mode. The maximum amplitude corresponds to the pump laser repetition rate being equal to a sub-harmonic frequency of the micropillar acoustic mode. The amplitude of the vibrational mode is determined by measuring the surface displacement using a probe laser and a Sagnac interferometer [1].
Collaboration
- Daniel Garcia, Jean-Louis Thomas, Bernard Perrin (Acoustics for nanosciences team)
Recent publications
[1] C. Lagoin, B. Perrin, P. Atkinson, D. Garcia-Sanchez, High spectral resolution of GaAs/AlAs phononic cavities by subharmonic resonant pump-probe excitation, Phys. Rev. B 99, 060101(R) (2019). https://hal.archives-ouvertes.fr/hal-02096499v1
[2] D. Garcia-Sanchez, S. Déleglise, J.-L. Thomas, P. Atkinson, C. Lagoin, B. Perrin, Acoustic confinement in superlattice cavities, Physical Review A 94, 033813 (2016). https://hal.archives-ouvertes.fr/hal-01402501v1
