- Experimental results are presented to substantiate that highly concentrated sunlight can pragmatically produce the same extent, rate, and type of photothermal tissue damage ordinarily generated with laser fiber-optic surgery. Typically, it is intense flux, rather than coherence, that renders laser light unique in generating rapid, highly localized tissue coagulation and ablation. The spectral properties of both biological tissue and available optical fibers render visible and near-infrared lasers as best suited for penetrative (as opposed to superficial) surgery. Solar photons are also viable candidates for such radiative surgery, provided they can be concentrated to the flux levels of surgical lasers, coupled into an optical fiber, and efficiently delivered to a remote operating theater. The simplicity and potentially low cost of a solar surgery unit counterbalance its feasibility being restricted to mid-day hours in sunny regions. After a brief review of our solar fiber-optic concentrator, we report on the rates and dimensions of tissue death produced in fresh ex vivo chicken livers for a range of values of delivered power and exposure time. An approximate analytic model can account for some of the principal experimental findings. Our experimental results demonstrate that solar surgery can produce lesions up to several cm3 in volume, with a surgical efficacy as good as that of lasers for corresponding procedures. © 2003 American Institute of Physics.