The second-order nonlinear optical characteristics of a novel organic crystal, urea L-malic acid (ULMA), were studied. Both type I and type II phase-matching angles of the biaxial crystal ULMA were calculated, whose loci are in the Hobden class 9. The efficiencies of second harmonic generation (SHG) of ULMA and KDP at a fundamental wavelength of 1064 nm were compared by using the Kurtz powder method. The results showed that the nonlinear coefficient of ULMA is about 1.57 times of that of KDP. High SHG efficiencies were observed over a broad range of the spectrum when ULMA was pumped by outputs generated from an optical parameter oscillator. To our knowledge, it is the first report where continuous SHG at fundamental wavelengths from 1300 to 950 nm with ULMA was achieved.
© 2005 Chinese Optics LettersPDF Article