Since the near infrared spectrum (wavelength range of 750–1100 nm) is the region of highest physiological transmisivity, it is the optical communication gateway for the laser energy to propagate into the human body. This optical window also leads to nanoparticle-based approach where embedded nanoparticles absorb the laser light designed to address the specific diagnostic and therapeutic challenges of cancer therapy is exploited extensively in so called plasmonic photo thermal therapy (PPTT). A new tool that is under development for cancer/tumor treatment, in which embedded nanoparticles are manipulated to absorb the Near Infrared (NIR) laser light intensely, aiming at addressing the “nonselectivity” problem that exists in the conventional photo thermal therapy (PPT). The purpose is to seek therapy with a faster and accurate procedure with a comprehensive treatment plan aided with fast and accurate numerical simulations as well. Among all the nanostructures, the noble metal nanoparticles (such as nanoshells) could be tuned to have peak absorption cross section in the NIR spectrum which provide very intense local heating to burn the deeply embedded cancerous tissues and tumors rather than the healthy tissue. Experimental and numerical studies have shown that designed gold nanoshells can be used to remotely and optically induce hyperthermia by embedding certain amount of absorbing dominated gold nanoshells in tumors and then irradiated using NIR laser light. Advancing our capabilities such as modeling, characterization and design of complex nanostructures and their host media for various nanophotonic applications will also increase our effectiveness of induced hyperthermia for its future applications. The computational tools should bridge across the scales from nano to macro, and rapidly compare the predicted behavior of a large number of nanoparticles embedded in tissue so that experimental groups could concentrate laboratory efforts on those resulted configurations most likely to provide optimum results.
Hot electron spatial distribution under presence of laser light self-focusing in over-dense plasmas