C. S. Fang

Poling and characterization of nonlinear polymer DCNP/PEK-c thin films

Abstract Polyetherketone (PEK-c) guest–host polymer thin films doped with 3-(1,1-dicyanothenyl)-1-phenyl-4, 5-dihydro-1H-pryazole (DCNP) were prepared. The poling profiles of the polymer film were investigated by using the in situ second-harmonic generation (SHG) measurement. The corona poling condition was optimized by the poling profiles. The second-order nonlinear optical (NLO) coefficient χ 33 (2) =20.86 pm/V at λ=1064 nm was determined by using the Maker fringe method after poling under the optimal poling condition. The temperature stability of the second-order optical properties of the poled polymer film was measured by the in situ SHG intensity probing. Moreover, the relaxation of the electric field-induced polar orientation of the chromophores in the poled polymer film was measured by the thermally stimulated discharge current (TSDC) technique.

Study of modified tgs crystals

Abstract Based on the relation between the structure and spontaneous polarization of TGS crystal, some modified TGS crystals have been grown by doping with aniline-family dipolar moleculars, inorganic acids and metal ions in the crystals. The effects of different dopants on growth habit and pyroelectric properties were investigated. The experimental results show that the pyroelectric figure of merit (p/e) of these new modified TGS-ATGSP and ATGSAs are one time higher than that of pure TGS crystal. The main approach of study on the modification of TGS crystal is also discussed in this paper.

Study on the pyroelectric properties of TGS-PVDF composites

Abstract TGS-PVDF composite has been prepared in our laboratory and its dielectric and pyroelectric properties were analyzed. The dielectric constants, dielectric losses and pyroelectric coefficients of this composite with different component proportions have been measured, and their variations with temperature were observed. In addition, the figure of merit M has also been calculated. The D* value of the pyroelectric devices made from this composite even reach (5–7) × 107 cm · Hz1/2 · W−1 . The results have shown that TGS-PVDF composite has bright prospects in applications as a pyroelectric composite material.

Poling optimization and optical loss measurement of the polyetherketone polymer films

Abstract Polyetherketone (PEK-c) guest–host polymer thin films doped with 3-(1,1-dicyanothenyl)-1-phenyl1-4,5-dihydro-1H-pryazole were prepared. Through in situ second-harmonic generation (SHG), the corona poling temperature was optimized by measuring the temperature dependence of the in situ SHG signal intensity under the poling electric field. The second-order NLO coefficient χ 33 (2) =16.67 pm/V at λ=1064 nm was determined by using the Maker fringe method after poling condition. For the poled polymer films, the lower-order optical waveguide-transmission losses were measured at 632.8xa0nm. The measurements showed that the optical loss of the fundamental mode is less than 0.5xa0dBxa0cm−1 for TE polarization.

Thermal stability and transmission losses of the poled polyimide side-chain thin films

Abstract The new side-chain polyimide thin films have been prepared. Through in situ second-harmonic generation (SHG) measurement, the corona poling temperature has been optimized by measuring the temperature dependence of in situ SHG signal intensity under the poling electric field. The second-order NLO coefficient χ 33 (2) =5.6 pm/V at λ =1064 nm was determined by using Maker fringe method after poling the films at optimal poling condition. The depoling knee temperature of the poled polyimide films can reach up to 200°C. Their lower-order optical waveguide-propagation losses were measured at 632.8 nm. The measurements have shown that the optical loss of the fundamental mode is less than 1.0 dB cm −1 for TE polarization.

Growth mechanism of doped polar trigycine sulfate crystals

L-alanine and phosphoric acid doped triglycine sulfate (ATGSP) is a typical polar crystal. This crystal is quite different from the pure TGS crystal. The growth characterics of doped polar TGS crystals were revealed by measuring the growth rate, domain structure, hysteresis loops and X-ray topography in two polar ends of TGS and ATGSP crystals. The growth mechanism of doped TGS crystals is also discussed.

Measurement of the optical transmission modes and losses of the poled guest}host polymer NAEC/PEK-c planar waveguides

The polyetherketone (PEK-c) guest-host polymer planar waveguides doped with (4-nitro)-3-azo-9-ethyl-carbazole (NAEC) were prepared. The waveguide films were poled by corona-onset poling at elevated temperature (COPET), and the corona poling setup includes a grid voltage making the surface-charge distribution uniform. By using the prism-in coupling method, the dark-line spectrum given by the reflected intensity versus the angle of incidence have been obtained, and the optical transmission losses of mth modes have been measured for the poled polymer waveguides at lambda = 632.8 nm. The measurement result showed that the optical loss of the fundamental mode is less than 0.7 dB cm(-1) for the TE polarization

Electro-optical Properties and Temporal Stability of the Guest-Host DCNP/PEK-c Polymer Thin Film

The polyetherketone (PEK-c) guest-host system thin films in which the range of the weight percent of 3-(1,1-dicyanothenyl)-1-phenyl-4, 5- dihydro-1H-pryazole (DCNP) is from 20% to 50% were prepared. The predicted high value of electro-optical (EO) coefficient gamma(33) = 48.8 pm/V by using two-level model was obtained when the weight percent of DCNP in the polymer system is 40%, whereas EO coefficients are attenuated at higher chromophore loading then 40%. The temporal stability of the EO activity of the guest-host polymer was evaluated by probing the decay of the orientational order of the chromophores in the polymer system.

ADTGSP single crystal with high pyroelectric figure of merit

Abstract This paper reports the distribution coefficient of phosphoric acid in solid-liquid phases and the conditions for the stepwise synthesis of chemical materials of ADTGSP crystals. The transparent bulk ADTGSP crystals were grown by lowering temperature method. The pyroelectric, dielectric, ferroelectric properties of ADTGSP crystal were measured and it is found that this crystal possesses higher pyroelectric figure of merit than that of TGS and DTGS crystals.

Electro-optic properties of poled guest-host organic polymer DCNP/PEK-c thin films

shandong univ, inst crystal mat, state key lab, jinan 250100, peoples r china; acad sinica, inst semicond, beijing 100083, peoples r china