  Multilayer microparticles with a liquid core and a polycomposite
light-absorbing shell are important components of modern bio- and medical
technologies, in particular, as transport microcontainers in the system of
targeted delivery of therapeutic nanodoses to the desired region of the
biological tissues. For reliably opening the microcapsule shell by an optical
radiation and releasing the payload, it is necessary to dramatically increase
the light absorption of such a microcontainer. To this end, we propose
surrounding the microcapsule with specially added auxiliary nanoparticles,
which can accumulate optical energy near its surface and direct a concentrated
photonic flux to the target microcapsule thus leading to its booster heating.
Using numerical finite-difference time-domain (FDTD) calculations, we simulate
and examine the absorption dynamics of the near-infrared optical radiation in a
spherical microcapsule surrounded by solid nanoparticles of different optical
properties (metal, biocompatible dielectric). We show that due to light
scattering on nanoparticles, the optical field superlocalization in the "hot
regions" on the microcapsule surface occurs. The three-fold light absorption
enhancement can be achieved due to the addition of nanoparticles.
