We report a highly selective chemical interaction between single-walled carbon nanotubes and Triton X-100 according to nanotubes' electronic structure and diameter. The interaction is induced by laser irradiation at power densities down to 10(-2) mu W/mu m(2) but with photon energies matching those for electronic transition in nanotubes. Our experimental results point to a photon-induced chemical interaction of Triton X-100 with metallic nanotubes below 1.1 nm in diameter and indicate the selectivity being dictated by Fermi electrons and enhanced by curvature-induced strain.