Sn2P2S6 is a fast responding photorefractive ferroelectric material with very attractive properties for applications in the near infrared. It exhibits high electro-optic coefficients up to r T 111 = 174pm/V at 633nm and room temperature, large transparency range in the infrared (530–8000 nm), and a high photorefractive sensitivity. We show that modifying the growth conditions and doping with Te can efficiently improve the photorefractive properties of Sn2P2S6. Photorefractive two-beam coupling gain at 860 nm increases from about 2 cm-1 in conventional " yellow" Sn2P2S6 to about 7 cm-1 in Te-doped samples and 14 cm-1 in modified " brown" samples. We demonstrate self-pumped phase conjugating reflectivities above 50 % and rise time of about 50 ms for 2.5 W/cm2 pump intensity at 860 nm.
© 2005 Optical Society of AmericaPDF Article