Fig. 2.

Tissue irradiance profiles and strategies for controlled light delivery: (a) schematic representation of an optical fiber tip and the calculated irradiance profile (b) at its tip for $\mathrm{NA}=0.4$ and $\mathrm{NA}=0.1$; the diameter of the fiber core used in the calculation was $200\mu \mathrm{m}$ and values of absorption and scattering were chosen for a wavelength of 473 nm; (c) axial normalized intensity profile at fiber center, corresponding to the dashed lines in (b); (d) different irradiance profile obtained from different tip geometries (adapted from Vo-Dinh⁷⁰); (e) flexible illumination location from a coated tapered fiber (adapted from Ref. 71). Optical windows ($\approx 5\mu \mathrm{m}$ wide) were made along the tapered shaft. Using different light input angles, different zones are illuminated.