A selection of poly(norbornene-exo-dicarboximide) brush-type polymers decorated with a pendent azobenzene dye have been prepared for use as electro-optic (EO) hosts. These polymer brushes were employed as EO polymer hosts for a high molecular hyperpolarizability phenyl vinylene thiophene vinylene (FTC) chromophore guest. These polymer brushes contained methoxy or cyano azobenzene substituents, which were able to manipulate the π-electronic polarization, refractive index, and EO activity. The concentration of the azobenzene dye was increased from 6 to 38%, in order to find the optimum and to maximise the EO coefficient. The refractive index of the mixtures could also be tuned by changing the azobenzene content. Ultimately an EO coefficient of nearly 95 pm/V could be realized using a methoxy substituted azobenzene brush at a concentration of 25% with an added FTC chromophore.
As the numerical aperture (NA) increasing and process factor k 1 decreasing in 193nm immersion lithography, polarization aberration (PA) of projection optics leads to image quality degradation seriously. Therefore, this work proposes a new scheme for compensating polarization aberration. By simulating we found that adjusting the illumination source partial coherent factors σ out is an effective method for decreasing the PA induced pattern critical dimension (CD) error while keeping placement error (PE) within an acceptable range. Our simulation results reveal that the proposed method can effectively compensate large PA in actual optics.
We investigated the performance of terahertz quantum-well photodetectors (THz QWPs) experimentally and theoretically. The photocurrent spectra of both THz QWPs are measured and simulated considering the many-particle effects. The dark current mechanisms are also investigated experimentally and theoretically. Results show that many-particle effects must be considered in the design of the THz QWPs(FIG.1). Also, the scattering assisted tunneling dark current should also be noted to play a very important role in the total dark current of THz QWPs(FIG.2).
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