There are two key reasons resulted in the weak transverse magneto-optical effect of SPP one is the small magneto-optic coefficient of the magneto-optic materials, and the other is that the transverse spin of SPP is not circular, but elliptical. However, it is difficult to miniaturize the isolator based on the transverse magneto-optical effect of SPP due to the weak magneto-optical effect. SPP has transverse spin angular momentum (TSAM), which can induce a magneto-optical effect to realize a non-reciprocal transmission similar to the longitudinal spin angular momentum (LSAM) of light. Surface plasmon polariton (SPP) can break the diffraction limit and has excellent potential in integrated optics, especially after the improvement in the problem regarding high loss of SPP. So far, however, the devices created have typically been in large scales because the magneto-optical effect is mostly weak in these cases. Among these, the magneto-optical effect is still a hotspot. To achieve a more integrated optical isolator, many methods, such as the use of magneto-optical effect, topology, nonlinear effects and parity-time symmetry breaking, have been developed. Optical isolators based on non-reciprocal transmission are the key photonic elements in optical telecommunications and optical information. Our research provides a new perspective for creating highly integrated magneto-optical devices. Additionally, a smaller cavity has a stronger transverse magneto-optical effect in the same wavelength range. Benefiting from this, the transverse magneto-optical effect remains strong in a wide wavelength range. Moreover, the enhancement of the transverse magneto-optical effect through the coin paradox SOI is more substantial for smaller azimuthal mode number n.
The great performance of the optical isolator is attributed to the strong transverse magneto-optical effect, which is enhanced by the coin paradox SOI.
The maximum isolation ratio is greater than 60 dB with a corresponding insertion loss of about 2 dB. The simulation results of the non-reciprocal transmission properties of this optical structure show that a high-performance on-chip integrated optical isolator is obtained. We designed a simple on-chip integrated optical isolator made up of a metal–insulator–metal waveguide and a disc cavity filled with magneto-optical material to enhance the transverse magneto-optical effect through the coin paradox spin–orbit interaction (SOI).
0 kommentar(er)
