Showing papers by "Alex K.-Y. Jen published in 1994"
84 citations
TL;DR: In this paper, the authors demonstrate that it is possible to design chromophores that simultaneously exhibit large nonlinearity and good thermal stability, and with the synthesis of bis(4-hydroxyphenyl)thiobarbituric acid, they believe that it should be possible to covalently incorporate these and other rather nonlinear chromophore into poled polymers at high concentrations.
Abstract: In summary, the compounds reported here demonstrate that it is possible to design chromophores that simultaneously exhibit large nonlinearity and good thermal stability. Furthermore, with the synthesis of bis(4-hydroxyphenyl)thiobarbituric acid, we believe that it should be possible to covalently incorporate these and other rather nonlinear chromophores into poled polymers at high concentrations. Experiments to test this hypothesis are in progress.
72 citations
TL;DR: In this paper, it was shown experimentally that the ketene dithioacetal group is very effective as an electron-donating group in the design and synthesis of thermally stable and efficient second-order nonlinear optical chromophores.
Abstract: It is shown experimentally that the ketene dithioacetal group is very effective as an electron-donating group in the design and synthesis of thermally stable and efficient second-order nonlinear optical chromophores.
65 citations
TL;DR: In this article, theoretical and experimental studies of the second order nonlinear optical responses of donor-acceptor substituted conjugated compounds which consist of heteroaromatic moieties in place of the traditional benzenoid moieties are presented.
Abstract: We present theoretical and experimental studies of the molecular second order nonlinear optical responses of donor–acceptor substituted conjugated compounds which consist of heteroaromatic moieties in place of the traditional benzenoid moieties. Electric‐field‐induced second harmonic generation measurement at a fundamental wavelength of 1.907 μm demonstrated a twofold increase of the off‐resonant molecular hyperpolarizability of a heteroaromatic compound compared to its benzenoid counterpart. Results of theoretical calculations based on ab initio scheme are in good agreement with the experimental results.
57 citations
46 citations
TL;DR: Based on the dithiolydinemethyl type donors and tricyanovinyl acceptor, a new series of highly efficient (βµ= 940 −2400 × 10 −48 esu) and thermally stable (275 −315 °C) nonlinear optical chromophores have been developed as discussed by the authors.
Abstract: Based on the ‘unconventional’ dithiolydinemethyl type donors and tricyanovinyl acceptor; a new series of highly efficient (βµ= 940–2400 × 10–48 esu) and thermally stable (275–315 °C) thiophene derived nonlinear optical chromophores have been developed.
42 citations
TL;DR: In this article, an electro-optic coefficient r33 value of 10.8 pm/V measured at 1.52 μm was achieved, and the electrooptic activity maintained more than 80% of its initial value after 600 h at 120°C, and more than 60% after 700 h at 150°C.
Abstract: Guest–host poled polymers with large nonresonant electro‐optic activity and high temperature stability were obtained using heteroaromatic chromophores and high temperature optical polyimides. An electro‐optic coefficient r33 value of 10.8 pm/V measured at 1.52 μm was achieved. The electro‐optic activity maintained more than 80% of its initial value after 600 h at 120 °C, and more than 60% after 700 h at 150 °C.
32 citations
TL;DR: In this paper, optical chromophores were used as side-chains for polyimide sidechains with high electro-optic activity and long-term alignment stability at 100 °C for more than 500 h.
Abstract: Novel Mitsunobu and tricyanovinylation reactions have been employed to incorporate efficient nonlinear optical chromophores as side-chains into aromatic polyimides resulting in high electro-optic activity and long-term alignment stability at 100 °C for more than 500 h.
29 citations
TL;DR: A facile synthetic method has been developed to incorporate efficient nonlinear optical chromophores as side-chains into high temperature polyimides resulting in high electro-optic activity and long-term thermal stability at 90 °C for over one month.
Abstract: A facile synthetic method has been developed to incorporate efficient nonlinear optical chromophores as side-chains into high temperature polyimides resulting in high electro-optic activity and long-term thermal stability at 90 °C for over one month.
28 citations
TL;DR: In this article, the synthesis, electronic absorption and second-order nonlinear optical properties of a series of new dialkylamino electron-donor and rhodanine-methine electron-acceptor substituted conjugated compounds were described.
25 citations
TL;DR: In this article, a new synthetic method was developed to incorporate efficient nonlinear optical chromophores containing thiophene conjugating units and tricyanovinyl acceptors into methacrylate polymers.
Abstract: A new synthetic method is developed to incorporate efficient nonlinear optical chromophores containing thiophene conjugating units and tricyanovinyl acceptors into methacrylate polymers; this approach emphasizes the incorporation of tricyanovinyl groups into the pendant side chains after copolymerization of the precursor substituted acrylates with methyl methacrylate.
TL;DR: In this paper, the combination of efficient thiophene conjugating units and novel electron-donating and electron-accepting functional groups was used to achieve thermally stable polyimides that possess large second order nonlinear optical activity.
Abstract: In this paper, we report our recent developments in achieving thermally stable polyimides that possess large second order nonlinear optical activity We have developed several classes of novel chromophores based on the combination of efficient thiophene conjugating units and novel electron-donating and electron-accepting functional groups Through these developments, we have synthesized chromophores that possess nonresonant βμ values as high as 9100 × 10-48 esu measured at 19 µm These chromophores also possess improved thermal and chemical stabilities The incorporation of these chromophores in high temperature polyimides produces E-0 materials with high linear electro-optic coefficients (in excess of 15 μm/V at 13 μm) and long-term temporal stability at an elevated temperature of 150°C for more than 750 h
23 Sep 1994
TL;DR: In this paper, the authors developed two classes of highly efficient and thermally stable nonlinear optical chromophores using fused-thiophene and bithiophene as conjugating units.
Abstract: We have developed two classes of highly efficient and thermally stable nonlinear optical chromophores using fused-thiophene and bithiophene as conjugating units. Experimental studies indicate that the use of fused-thiophene or bithiophene as a (pi) conjugating bridge provides an excellent tradeoff between nonlinearity and thermal stability. In addition to the chromophore developments, we have employed new synthetic methodologies to obtain thermally stable poled polyimides.
15 May 1994
TL;DR: In this article, a thermally stable nonlinear optical chromophores based on the combination of efficient thiophene conjugating units and novel electron-donating and electron-accepting functional groups were developed.
Abstract: We have developed several classes of thermally stable nonlinear optical chromophores based on the combination of efficient thiophene conjugating units and novel electron-donating and electron-accepting functional groups. The incorporation of these chromophores into high temperature polymers produces high linear electro-optic coefficients and long-term thermal stability at elevated temperatures. Active Mach-Zehnder interferometers with a V(pi) phase shift of 50 volts and low attenuation (< 2 dB/cm) were fabricated. Thermal baking of the poled device demonstrated no change in activity after 30 minutes at 230 degree(s)C.
Journal Article•
TL;DR: In this paper, it was shown experimentally that the ketene dithioacetal group is very effective as an electron-donating group in the design and synthesis of thermally stable and efficient second-order nonlinear optical chromophores.
Abstract: It is shown experimentally that the ketene dithioacetal group is very effective as an electron-donating group in the design and synthesis of thermally stable and efficient second-order nonlinear optical chromophores.