Characterization of organic crystals for second-harmonic generation

Second-harmonic generation (SHG) is a common tech-nique with many applications. Common inorganic single -crystalline materials used to produce SHG light are effective using short IR/visible wavelengths but gener-ally do not perform well at longer, technologically rele-vant IR wavelengths such as 1300, 1550, and 2000 nm. Efficient SHG materials possess many of the same key material properties as terahertz (THz) generators, and certain single-crystalline organic THz generation materi-als have been reported to perform at longer IR wave-lengths. Consequently, this work focuses on characterizing three efficient organic THz generators for SHG, namely, DAST (trans-4-[4-(dimethylamino)-N-methylstilbazolium] p-tosylate), DSTMS (4-N,N-dimethylamino-4'-N'-methylstil bazolium 2,4,6-trimethylbenzenesulfonate), and the recently discovered generator PNPA ((E)-4-((4-nitrobenzylidene)ami no)-N-phenylaniline). All three of these crystals outper-form the beta-barium borate (BBO), an inorganic material commonly used for SHG, using IR pump wavelengths (1200-2000 nm). (c) 2023 Optica Publishing Group