Interferometric inscription of volume Bragg gratings in a commercial high refractive index glass (S-TIH53) by 400 nm femtosecond (fs) laser pulses
in: Temporal Proceedings (2012)
Volume Bragg gratings (VBGs) in specific glasses offer great potential to integrate a wavelength selective mirror in other transmitting components. Furthermore, VBGs could be used for reduction of bandwidth, beam combination or pulse compression with chirped VBGs in a single element. In this paper we present investigations on such VBGs which are based on a periodic refractive index modulation. This modulation can be generated by a holographic illumination in photosensitive materials or by high intensity fs laser radiation for materials without classical UV-photosensitivity. Often point-by-point inscription is used to fabricate VBGs by focusing the light tightly into the material and by scanning the whole sample. However, extreme mechanical requirements for positioning and moving of the sample make this technique less applicable. We demonstrate here VBGs inscribed with a non-scanning technique in the commercial glass S-TIH53 from OHARA using a Talbot-interferometer. In this case the sample is located directly in the area of interference. As a laser source we use a frequency-doubled Ti:Sa-amplified laser at a wavelength of 400 nm and with pulses of a length in the order of 300 fs (FWHM). We characterize these gratings by external Bragg reflection measurements. Gratings with a length of about 1mm and a height of 0.1 mm have been realized, which prove for the first time the feasibility of fs laser pulse inscription of VBGs at 400nm wavelength for this type of commercial glass.