PURPOSE: To obtain the material which is usable for semiconductor laser beams and has a high sensitivity, small dark attenuation and sufficient heat resistance by using a compd. having a specific chemical structure as a sensitizing dye.

CONSTITUTION: Prescribed ratios of zinc oxide, the sensitizing dye for laser beams, a sensitizing assistant, and a resin binder is charged into a solvent, such as toluene and a coating liquid is prepd. by using a mixing and dispersing machine. This coating liquid is applied on one surface of a base and is dried to form a photosensitive layer. The sensitizing dye contains the compd. expressed by formula. In the formula, m1 and m2 denote 0 or ≥1 integer; X1 to X8 denote a hydrogen atom or halogen atom; at least one member of X1 to X8 denote a halogen atom; Y denotes an acid group. The required characteristics are attained by this sensitizing dye.