Photorefractive waveguides in He^+ implanted pure and Te-doped Sn_2P_2S_6

We have demonstrated for the first time, to the best of our knowledge, photorefractive two-wave mixing in He+ implanted waveguides in one of the most promising materials for infrared plaotorefractive applications, the ferroelectric semiconductor Sn2P2S6. The high optical nonlinearity is preserved after implantation and at the telecommunication wavelength lambda= 1.55 mu m, a maximal two-wave mixing gain of 2.5 cm(-1) has been measured in Te-doped waveguides. In the nominally pure material an increase of the effective number of traps after implantation has been observed, resulting in all increase of the two-beam coupling gain by a factor of almost 2 in the 633-1064 nm spectral range. In 1% Te-doped Sn2P2S6 the effect of ion implantation to the photorefractive response is completely different than it) pure materials. While the dominant contribution by holes is not considerably affected, a strong, thermally induced charge compensation is observed in the He+ implanted Te-doped waveguides. (C) 2009 Optical Society of America