2024 : 4 : 13
Abolghasem Daeichian

Abolghasem Daeichian

Academic rank: Associate Professor
ORCID: https://orcid.org/0000-0002-6318-579X
Education: PhD.
ScopusId: 55916844500
Faculty: Engineering
Address: Arak University
Phone: 08632625436


Cavity-assisted coherent feedback cooling of a mechanical resonator to the ground-state in the unresolved sideband regime
quantum system, ground-state cooling, optomechanical system, coherent feedback
Journal Journal of Physics B: Atomic, Molecular and Optical Physics
Researchers Dariush Mansouri ، Behrooz Rezayi ، Abolfazl Ranjbar ، Abolghasem Daeichian


This paper presents a cavity-assisted coherent feedback scheme to cool a mechanical resonator to the ground-state in a weak optomechanical coupling setup. Based on the theory of sideband cooling, resolved sideband regime is a mandatory condition for the ground-state cooling (GSC) in optomechanical systems. Assisted cooling and feedback cooling methods have been proposed and shown to be beneficial for cooling in unresolved sideband cases. In this paper, a cooling method is proposed by combining both approaches. In the proposed method, a coherent feedback loop is added to a cavity-assisted optomechanical system to enhance the cooling performance. The proposed feedback aims to reach the mechanical ground-state in the USR. Rate equations of the mechanical resonator are derived, and then, by applying Fermi's golden rule and analyzing the fluctuation spectrum of the optical force, optimal conditions for cooling are obtained. Results show that applying coherent feedback, improves the cooling performance of the system significantly and it is possible to achieve GSC in unresolved sideband regime (USR). Moreover, it is shown that the proposed method is capable of cooling the mechanical resonator to much lower energy levels than it is achievable in cavity assisted method.