FREQUENCY-SHIFTING THROUGH CASCADED 2ND-ORDER PROCESSES IN A N-(4-NITROPHENYL)-L-PROLINOL CRYSTAL

We exploit the high second-order susceptibility of the organic crystal N-(4-nitrophenyl)-L-prolinol to accomplish, through a cascaded second -order process, wavelength conversion of a signal pulse (from 1.16 to 1.14 mu m) under the action of a pump pulse (at 1.15 mu m). In a 2.8-m m-thick crystal, wavelength conversion with unit gain was obtained wit h a pump peak intensity as low as 9 MW/cm(2). At low intensities, in t he limit of negligible conversion where the cascading effect can be de scribed through an effective third-order susceptibility, we derive \ch i(eff)((3))\ approximate to 2.4 x 10(-17) m(2)/V-2, which is similar t o 10(2) larger than the nonresonant chi((3)) of conjugated polymers or semiconductors. (C) 1998 Optical Society of America.