Two-photon or multi-photon chromophores having a conjugated pi-electron system with donating groups at each end of the pi-electron system providing charge-transfer properties, and having quaternary amine groups that can enhance the solubility of the chromophore in water. The dovetail includes a pair of supporting tangs. The silicon film used in forming the active region comprises a plurality of substantially single-crystal silicon crystal grains, and regions including crystal grain boundaries which exist in the longitudinal direction of the channel formation region 26 are removed.