A method of writing plane holographic gratings Bragg-matched for reflection in the infrared in a photorefractive material using shorter wavelength light through a face perpendicular to the grating planes. The writing beam wavelength is selected to be within the photorefractive sensitivity range of the...http://www.google.es/patents/US5491570?utm_source=gb-gplus-sharePatente US5491570 - Methods and devices for using photorefractive materials at infrared wavelengths
Methods and devices for using photorefractive materials at infrared wavelengths
