Acoustic Torsional Mechanical Oscillator Driven by Wave-Matter Orbital Angular Momentum Transfer with Quality Factor >1000

The experimental realization of a macroscopic mechanical oscillator driven by the nondissipative transfer of angular momentum from sound waves to matter is presented, with quality factor up to Q ≈ 2000. This performance is two orders of magnitude higher than previously reported values Q ≈ 10. This result is achieved through the use of a monolithic metallic torsional pendulum and improved assembling method of the constitutive parts of the apparatus. This allows a substantial reduction of the internal losses associated with the imaginary part of the complex shear modulus compared with previous attempts using photocurable resin materials.