Nonreciprocal magnon laser in a spinning cavity optomagnonic system

We introduce a novel, to the best of our knowledge, method to achieve a highly efficient nonreciprocal magnon laser within a spinning cavity optomagnonic system, which integrates a magnon mode and two optical modes. The rotation of the YIG sphere triggers the Barnett effect in the magnon mode and the Sagnac effect in the optical modes. The directional input of a pump light leads to opposite Sagnac-Fizeau frequency shifts in these modes. By adjusting the angular velocity, we can simultaneously control both the Barnett and Sagnac effects. Significantly, increasing the spin angular velocity enhances the system's nonreciprocity and magnon gain, yielding an isolation rate of 38.7 dB and a low-threshold magnon laser. This method presents a promising avenue for developing a nonreciprocal magnon laser, with implications for spintronics and the advancement of nonreciprocal optical devices.