Magnetic Actuation of Magneto-Photonic Particles for Targeted Light Delivery

The capability to deliver light of desired properties (wavelength, intensity, polarization, etc.) to any target spot in a medium has broad relevance for applications across biology and biomedicine to nano-chemistry and radiation therapy. Key challenges for such delivery are that (i) it exhibits high directionality and significant selectivity for desired light properties, that (ii) it be adaptively controlled with a non-invasive mechanism, and that (iii) it does not require direct line-of-sight access to the target spot. However, existing platforms for light delivery, such as nanoscale scatterers or photonic surfaces with subwavelength patterns, have their limitations on actively orienting the direction of light scattering.<br/>Here, we discuss a concept of a magneto-photonic particle with an optically active surface for targeted light delivery where the particle can be remotely actuated with a magnetic field. The photonic surface that provides sophisticated control of direction of scattering properties is patterned onto the particle using nanoimprint lithography, which enables the production of complex features at nanoscale resolution, while being highly scalable. Once the orientation of the pattern of a photonic surface and direction of magnetization are synchronized, the position of the target spot of light delivery can be controlled with an external magnetic field. We believe our approach can be used to realize a platform that enables targeted delivery of light within relevant biological windows, with possible applications in opto-genetics, neural stimulation, and localized heating.