  Over the past few decades, optical manipulation has emerged as a highly
successful tool in various fields, such as biology, micro/nanorobotics, and
physics. Among the different techniques, the transverse slot optical waveguide
has shown remarkable potential in enhancing the field and significantly
improving optical trapping capabilities. Additionally, microring resonators
have demonstrated the ability to enhance the field at specific resonance
wavelengths, enabling the manipulation and capture of particles. In this study,
we investigated the impact of the structure on nanoparticle capture by
introducing a 50 nm transverse slot in a 5 {\mu}m microring resonator. Through
the integration of a transverse slot in the microring resonator, we observed a
substantial increase in the maximum bound optical power for a nanosphere with a
refractive index of 1.6 and a diameter of 50 nm, reaching 3988.8 pN/W. This
value is 2292 times higher than the maximum optical force in a straight
waveguide and 2.266 times higher than the maximum optical force in a microring
resonator. The proposed structure significantly enhances the optical trapping
capabilities for nanoscale particles, thus paving the way for the development
of advanced micro/nanomanipulation techniques.
