Cavity optomechanics

In our modern information age, nano- and micromechanical oscillators are indispensable technologies that enable navigation, timing, motional sensing and wireless communication. They are used in particular for radio frequency filtering as well as for measuring rotation and acceleration and are employed commercially in cell phones, automobiles and airplanes.

The quality factor of mechanical oscillators can be extremely high, even in the gigahertz range, and in general, they have unique advantages over their electronic counterparts.

In the past decade, a technological and scientific revolution has occurred with respect to the efficient, coherent operation of such mechanical devices: In analogy to the previous quantum control of atoms, ions, and molecules and, later, electrical circuits, nano- and micromechanical devices can now be interrogated and controlled at the quantum level using optical fields, thus establishing the field of cavity optomechanics.

By employing optical resonators that greatly enhance otherwise weak radiation pressure, the resonant build-up of laser light in an optical cavity gives rise to parametric coupling of the optical and mechanical degrees of freedom, enabling cooling, amplification, and unprecedentedly sensitive detection of mechanical motion. The latter includes microwave circuits with vibrating capacitive elements.

Si photonic crystal nanobeam cavity

Scanning electron microscope image of a freestanding quasi-one-dimensional silicon photonic crystal nanobeam cavity with a 40-nm slot.

Ask the expert

Paul Seidler

IBM Research scientist

EU projects

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Cavity Quantum Optomechanics

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Optomechanical Technologies

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Hybrid Optomechanical Technologies

Our focus

Our current research is focused on exploiting electromechanical coupling in combination with optomechanical coupling for the efficient transduction of signals from the electrical to the optical domain and ultimately extending the technology into the realm of interconversion of single microwave and optical qubits.

We are investigating photonic crystal cavities based on non-centrosymmetric materials and exploit the inverse piezo effect to actuate the mechanical modes at microwave frequencies. III–V materials are of particular interest because of the high index of refraction, transparency in the visible (for some materials), and the possibility of integration on oxide-on-silicon substrates for fabrication of photonic circuits.

Of particular interest are devices with slot structures, which are expected to exhibit particularly large moving-boundary contributions to the optomechanical coupling due to an ultra-small mode volume.

Selected publications

[1] P. Seidler,
Optimized process for fabrication of free-standing silicon nanophotonic devices,”
Journal of Vacuum Science & Technology B 35(3), 031209 (2017).

[2] K. Schneider and P. Seidler,
Strong optomechanical coupling in a slotted photonic crystal nanobeam cavity with an ultrahigh quality factor-to-mode volume ratio,”
Optics Express 24(13) 13850-13865 (2016).

[3] P. Seidler, K. Lister, U. Drechsler, J. Hofrichter, and T. Stöferle,
Slotted photonic crystal nanobeam cavity with an ultrahigh quality factor-to-mode volume ratio,”
Optics Express 21(26), 32468-32486 (2013).