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bernd.schulte@aei.mpg.de +49 511 762-17025 |

Bernd started 2016 as a PhD student after having written his Master’s thesis in the group.

His work focused on the characterization and implementation of an optomechanical cavity, one sub system of an all optical coherent quantum noise *cancellation (CQNC) scheme, proposed by *M. Tsang and C. M. Caves[1].

This optomechanical cavity consists of a mechanical oscillator placed within an optical cavity. The goal of this setup is to be susceptible to quantum radiation pressure shot noise. For this purpose, the optomechanical cavity will be placed in a cryostat to decrease thermal noise so that the dominating noise will be quantum radiation pressure shot noise. For this experiment Bernd develops a suitable optomechanical cavity and the characterization a characterization setup. This should lead to a final measurement of the light enhanced optomechanical coupling strength which is one of the key parameters for an all optical CQNC scheme.

If the optomechanical cavity leads to a quantum backaction susceptible measurement of the mechanical oscillator the light on which the quantum backaction is imprinted will be sent to a cavity. The second cavity consists of a nonlinear crystal and a beam splitter which will, under right conditions, destructively interfere with the quantum backaction noise.

The conditions for this setup are given in [2],[3].

- M. Tsang and C. M. Caves, ‘Coherent quantum-noise cancellation for

optomechanical sensors’, Phys. Rev. Lett. 105 (2010), 123601) - M. H. Wimmer, D. Steinmeyer, K. Hammerer, and M. Heurs:
*Coherent cancellation of backaction noise in optomechanical force measurements*, Phys. Rev. A**89**, 053836 (2014), - Steinmeyer, D., ‘Subsystems for all-optical coherent quantum-noise cancellation, PhD thesis,

Leibniz Universität Hannover, 2019.