Evidence of double-quantum photoeffect observed at photostimulated formation of fractal aggregated in silver colloids under low-intensity light

Summary form only given. Experimental results obtained for the proposed qualitative theory prove the hypothesis on the two-photon nature of photoemission within range 550 to 950 nm. Note that observation of an enhancement in nonlinear optical processes by fractal nanostructures was so far reported concerning only nonlinear optical phenomena of a degenerate four-wave mixing type. However, manifestations of two photon photoeffect in such low-intensity optical fields have been observed.