Seyed K. Alavi | Searcharxiv

arXiv2025

Interference-enhanced optical force detection of weak light fields using a levitated nanoparticle

Optically levitated nanoparticles in vacuum provide a highly sensitive platform for probing weak light-matter interactions. In this work, we present an interference-based method to amplify the optical force exerted by a weak field on a nanoscale particle trapped in an optical tweezer. By allowing the weak field to interfere with the strong trapping beam, we significantly enhance the optical force compared to the case without interference. This amplified optical force enables the detection of the weak field through the particle's motion, reaching picowatt-level sensitivity under moderate vacuum conditions. We further discuss the potential of this approach for developing an ultrasensitive, nondestructive detector of light fields and for exploring optomechanical interactions at the single-photon level.

quant-ph↗

arXiv2023

Optomechanically induced optical trapping system based on photonic crystal cavities

Optical trapping has proven to be a valuable experimental technique for precisely controlling small dielectric objects. However, due to their very nature, conventional optical traps are diffraction limited and require high intensities to confine the dielectric objects. In this work, we propose a novel optical trap based on dielectric photonic crystal nanobeam cavities, which overcomes the limitations of conventional optical traps by significant factors. This is achieved by exploiting an optomechanically induced backaction mechanism between a dielectric nanoparticle and the cavities. We perform numerical simulations to show that our trap can fully levitate a submicron-scale dielectric particle with a trap width as narrow as 56 nm. It allows for achieving a high trap stiffness, therefore, a high Q-frequency product for the particle's motion while reducing the optical absorption by a factor of 43 compared to the cases for conventional optical tweezers. Moreover, we show that multiple laser tones can be used further to create a complex, dynamic potential landscape with feature sizes well below the diffraction limit. The presented optical trapping system offers new opportunities for precision sensing and fundamental quantum experiments based on levitated particles.

physics.optics↗