Xiangbing Sun

Synthesis, crystal structure and saturable absorption in the near-IR regions of a new copper complex of dmit: hexadecyltrimethylammonium bis (2-thioxo-1,3-dithiole-4,5-dithiolato)-copper

A new copper complex of dmit, hexadecyltrimethylammonium bis(2-thioxo-1,3-dithiole-4,5-dithiolato)-copper([C16H33(CH3)3N][Cu(dmit)2], abbreviated as CTCU, C16H33(CH3)3N = hexadecyltrimethylammonium, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate) has been synthesized and its structure determined by X-ray diffraction. The saturable absorption of CTCU at 1053 nm shows promise as a Q-switch dye in the near IR regions.

Study on the third-order nonlinear optical properties of bis(tetraethylammonium)bis(1,3-dithiole-2-thione-4,5-dithiolato)mercury

A dmit2− salt: bis(tetraethylammonium)bis(1,3-dithiole-2-thione-4,5-dithiolato) mercury (EMDT) was synthesized. The optical Kerr effect (OKE) signal of its acetone solution was measured by the femtosecond optical Kerr gate technique. Using the CS2 OKE signal as a reference signal measured under identical conditions, the third-order optical nonlinear susceptibility, χ(3), of the sample solution was obtained as about 6.193 × 10−14 esu at the concentration of 1.39 × 10−4 M. The second hyperpolarizability for molecular EMDT was estimated to be as large as 2.73 × 10−31 esu. Its response time was about 184 fs, which is believed to be the contribution from the delocalized electrons.

Raman characteristics of Nd:LuxY1?xVO4 series crystals

An efficient self-stimulated Raman laser of Nd:LuxY1−xVO4 (x = 0.1, 0.26, 0.41, 0.61, 0.67 and 0.8) series crystals was demonstrated for the first time. Compared to YVO4, the relative Raman gain coefficients were determined by studying their spontaneous Raman scattering spectra. With the largest thermal conductivity, excellent energy storage capability and moderate Raman gain coefficient, the Nd:Lu0.26Y0.74VO4 crystal presented the best Raman laser performance: 2.3 W average output power, 71 μJ single pulse energy and 26.3 kW peak power. The results indicated that the Nd:Lu0.26Y0.64VO4 crystal should be an excellent self-Raman laser material.

Third-order optical nonlinearity of a novel material : [ (C4H9)4N] [Co (dmit )2]

A novel dmit organometallic complex—[(C4H9)4N][Co(dmit)2] (dmit2− = 4,5-dithiolate-1,3-dithiole-2-thione), abbreviated as BuCo, is synthesized and its third-order optical nonlinearity of the acetone solution is characterized using the Z-scan technique with a 40-ps pulse width at 1064 nm. Z-scan curves show that BuCo sample solution possesses the negative nonlinear refraction, exhibiting a self-defocusing effect. In addition, the two-photon absorption has been observed in BuCo. The effective molecular second-order hyperpolarizability γeff of the BuCo molecule was estimated to be as large as 5.60 × 10−31 esu, suggesting BuCo is a potential material for optical device applications.

A diode-pumped passively Q-switched c-cut Nd:Lu0.1Y0.9VO4 laser

The continuous wave and pulsed laser performances of a laser-diode-end-pumped c-cut Nd:Lu0.1Y0.9VO4 crystal have been demonstrated for the first time. The small emission cross section and appropriate upper level lifetime result in the c-cut Nd:Lu0.1Y0.9VO4 crystals having excellent pulsed laser performance. When the pulse repetition rate was 6.4 kHz, the shortest pulse width, the largest pulse energy and the highest peak power were found to be 1.9 ns, 104.7 μJ and 55.1 kW, respectively, using a Cr4+:YAG crystal as the saturable absorber. These results were much better than those for an a-cut Nd:Lu0.1Y0.9VO4 crystal under the same conditions.

Nonlinear optical studies of an organo-metallic complex by Z-scan technique

The nonlinear optical properties of an organo-metallic compound, tetrabutylammonium bis(2-thioxo-1,3-dithiole-4,5-dithiolato)aurum, abbreviated as BuAu, are investigated by Z-scan technique with 28 ps pulse width at 532 nm. Strong reverse saturable absorption has been found, the effective excited-state absorption cross section is obtained as σeff = 1.818×10-17 cm2. The material also shows self-defocus and the nonlinear optical refractive index is measured as n2 = -1.341×10-12 esu with the concentration of 2×10-3 mol/L. All the results suggest that this material has potential application as optical devices.