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

Abstract

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 photorefractive applications, the ferroelectric semiconductor Sn2P2S6. The high optical nonlinearity is preserved after implantation and at the telecommunication wavelength λ=1.55 μm, 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 an 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 in 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.