We measured, for the first time to our knowledge, a net two-beam coupling gain in an organic crystal. Our photorefractive measurements were carried out in nominally pure organic crystals of 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium toluene-p-sulfonate (DAST). Because of its large electro-optic coefficient, r11 = 83 pm/V at λ = 750 nm, and a photoconductivity of up to σ = 6.7 × 10-12 Ω-1 cm-1 at intensity I = 570 mW/cm2, DAST showed a gain of 2.2 cm-1 for an absorption of α = 1.8 cm-1. With grating buildup times below 1 s at light intensities of 300 mW/cm2, DAST is a promising candidate for photorefractive applications in the near infrared.
© 1996 Optical Society of America
S. Follonier, Ch. Bosshard, F. Pan, and P. Günter, "Photorefractive effects observed in 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium toluene-p-sulfonate," Opt. Lett. 21, 1655-1657 (1996)