A laminated laser window having an inner layer transparent to light having wavelengths between 3.5 micrometers and 12 micrometers and having as an outer surface a nanometric-thick outer layer of SiO2. The window allows the passage of light within this wavelength range, for example from a CO2 laser. In The SiO2 outer layer maintains biocompatibility when used in laser devices for insertion into externally accessible bodily cavities.