We study the optical properties of amorphous GaAs1-xNx films grown by radio frequency magnetron sputtering method with different N-2 partial pressures. The surface morphology, the optical absorption, the Raman spectra, and optical constants of the films with different N-2 partial pressures are reported. The appearance of the Raman peak at 245 cm(-1) of "GaAslike" and a shoulder at about 750 cm(-1) related to GaN indicates the formation of GaN clusters in GaAs matrix. The roughness decreases and the optical band gap of amorphous GaAs1-xNx films moves to short wavelength with increasing N-2 partial pressure. The refractive index and the extinction coefficient of the films decrease with increasing N-2 partial pressure, and it has been found that the amorphous GaAs1-xNx films with nonzero N-2 partial pressure are transparent in red and near infrared wavelength regions. (c) 2006 American Vacuum Society.