Polyvinylidene fluoride—piezoelectric polymer for integrated infrared optics applications

The suitability of polyvinylidene fluoride films for IR integrated optics applications was demonstrated. Polyvinylidene fluoride is a piezoelectric polymer, which demonstrates high transparency in the middle-IR and has several transparent windows in the far-IR. The fabrication of cylindrical microlenses and microlens arrays by CO₂ laser irradiation of polyvinylidene fluoride substrates has been demonstrated. Pseudo-spherical microlenses were also fabricated by direct laser writing. Strong piezoelectric properties, high chemical resistance, stability to UV radiation and high continuous-use temperature make PVDF suitable for various IR integrated optics applications.     

基于交联聚芳醚体系的新型二阶非线性光学材料的研究

采用逐步聚合和后功能化方法,合成了可交联的新型二阶非线性光学聚芳醚体系,该聚合物具有优良的溶解性和成膜性。采用UV-Vis光谱研究了聚合物薄膜中挂接的蒽基团与N,N-（亚甲基二苯基）双马来酰亚胺交联剂之间的Diels-Alder（DA）交联过程,结果表明聚芳醚薄膜在110℃时,15min能够交联完全。将发色团Chro-1掺杂到聚合物中,加入交联剂通过旋转涂膜,研究交联体系的二阶非线性光学性质,当发色团浓度为10%（质量分数）时,采用简单反射法测量聚合物薄膜电光系数r33为6.5pm/V（1.31μm）,并测得常温下取向稳定性,10d后电光系数能够保持在初始值85%。     

Multilayer polymer microchip capillary array electrophoresis devices with integrated on-chip labeling for high-throughput protein analysis

It is desirable to have inexpensive, high-throughput systems that integrate multiple sample analysis processes and procedures, for applications in biology, chemical analysis, drug discovery, and disease screening. In this paper, we demonstrate multilayer polymer microfluidic devices with integrated on-chip labeling and parallel electrophoretic separation of up to eight samples. Microchannels were distributed in two different layers and connected through interlayer through-holes in the middle layer. A single set of electrophoresis reservoirs and one fluorescent label reservoir address parallel analysis units for up to eight samples. Individual proteins and a mixture of cancer biomarkers have been successfully labeled on-chip and separated in parallel with this system. A detection limit of 600 ng/mL was obtained for heat shock protein 90. Our integrated on-chip labeling microdevices show great potential for low-cost, simplified, rapid, and high-throughput analysis.     

Use of grating theories in integrated optics.

Recently [Opt. Lett. 25, 1092 (2000)], two of the present authors proposed extending the domain of applicability of grating theories to aperiodic structures, especially the diffraction structures that are encountered in integrated optics. This extension was achieved by introduction of virtual periodicity and incorporation of artificial absorbers at the boundaries of the elementary cells of periodic structures. Refinements and extensions of that previous research are presented. Included is a thorough discussion of the effect of the absorber quality on the accuracy of the computational results, with highly accurate computational results being achieved with perfectly matched layer absorbers. The extensions are concerned with the diversity of diffraction waveguide problems to which the method is applied. These problems include two-dimensional classical problems such as those involving Bragg mirrors and grating couplers that may be difficult to model because of the length of the components and three-dimensional problems such as those involving integrated diffraction gratings, photonic crystal waveguides, and waveguide airbridge microcavities. Rigorous coupled-wave analysis (also called the Fourier modal method) is used to support the analysis, but we believe that the approach is applicable to other grating theories. The method is tested both against available numerical data obtained with finite-difference techniques and against experimental data. Excellent agreement is obtained. A comparison in terms of convergence speed with the finite-difference modal method that is widely used in waveguide theory confirms the relevancy of the approach. Consequently, a simple, efficient, and stable method that may also be applied to waveguide and grating diffraction problems is proposed.     

Linker-free directed assembly of high-performance integrated devices based on nanotubes and nanowires

Advanced electronic devices based on carbon nanotubes (NTs) and various types of nanowires (NWs) could have a role in next-generation semiconductor architectures. However, the lack of a general fabrication method has held back the development of these devices for practical applications. Here we report an assembly strategy for devices based on NTs and NWs. Inert surface molecular patterns were used to direct the adsorption and alignment of NTs and NWs on bare surfaces to form device structures without the use of linker molecules. Substrate bias further enhanced the amount of NT and NW adsorption. Significantly, as all the processing steps can be performed with conventional microfabrication facilities, our method is readily accessible to the present semiconductor industry. We use this method to demonstrate large-scale assembly of NT- and NW-based integrated devices and their applications. We also provide extensive analysis regarding the reliability of the method.     

Self-characterization of linear and nonlinear adaptive optics systems

We present methods used to determine the linear or nonlinear static response and the linear dynamic response of an adaptive optics (AO) system. This AO system consists of a nonlinear microelectromechanical systems deformable mirror (DM), a linear tip-tilt mirror (TTM), a control computer, and a Shack-Hartmann wavefront sensor. The system is modeled using a single-input-single-output structure to determine the one-dimensional transfer function of the dynamic response of the chain of system hardware. An AO system has been shown to be able to characterize its own response without additional instrumentation. Experimentally determined models are given for a TTM and a DM.     

Improvement of emission efficiency in polymer light-emitting devices based on phosphorescent polymers

We report improvement of emission efficiency in polymer light-emitting devices (PLEDs) employing phosphorescent polymers. A hole-blocking layer was inserted between the emissive layer and the cathode to enhance recombination efficiency for the injected holes and electrons. Aluminum(III)bis(2-methyl-8-quinolinato)4-phenylphenolato (BAlq) was used for the hole-blocking layer. The resultant PLEDs exhibited significant improvement of emission efficiency. The respective external quantum efficiencies for red, green and blue PLEDs were 6.6, 11 and 6.9%. These values are very high compared with those based on conventional fluorescent polymers.     

SOI射频集成器件研制

提出了包含射频有源和无源器件的sOI集成结构及工艺方案,在同一SIMOX衬底上制作了射频LDMOS、NMOS、电感、电容、电阻和变容管。核心的LDMOS、NMOS和电感器件均获得了优良的电学特性：0．25μm栅长的LDMOS截止频率和关态击穿电压分别为19．3GHz和16．1V;而0．25μm栅长的NMOS对应参数则为21．3GHz和4．8V;采用开发的局部介质增厚技术后,2nH、5nH、10nH螺旋电感的最大品质因数分别达到了6．5、5．0、4．0,相对于不采用此技术的电感(最大品质因数分别为4．3、3．2、2．3),分别改善了77％,58％,49％。     

Effects of radiation-mode coherent coupling in integrated optics discontinuities

We study the coupling of radiation modes in successive integrated optical discontinuities. This study is performed for the spectral domain of both the radiation and the guided local modes. Analytical expressions for the coupling between groups of radiation modes themselves for different types of discontinuities are developed. The effect of discretization, required for representation of a physical structure by successive discontinuities, is also studied. This study is a preliminary for the realization of a numerical propagation method. In an application, the effects of coherent coupling of radiation modes in successive abrupt bends are presented.     

Methoxyphenyl indenopyrazoloquinoline derivatives as green fluorescent emitters for polymer based electroluminescent devices

Paper reports synthesis aspects and spectroscopic properties of three newly synthesized trimethyl derivatives of methoxyphenyl indenopyrazoloquinoline (MPTM-IPQ) compounds representing a subclass of azafluoranthene dyes. The spectroscopic studies are supplemented by cyclic voltammetry measurements and quantum-chemical calculations using DFT/TDDFT/PCM method at the B3LYP/6-31+G(d,p) level of theory. The absorption/fluorescence processes appear to be weakly dependent on the side position of the methyl radicals exhibiting the first absorption band in the region of 445-450 nm and the fluorescence band in the range of 530-540 nm. A considerable Stokes shift (85-100 nm) originates in all the dyes mainly from the solute relaxation in the excited state. The electroluminescence devices with an active PVK layer doped by MPTM-IPQ dyes have been designed. All the devices exhibit green electroluminescence with the emission maximum being rather weakly dependent on the type of the fluorescent dopant. The obtained results demonstrate that a series of newly synthesized MPTM-IPQ dyes may be considered as perspective green fluorescent emitters for electroluminescent applications.     

The finite element method in problems of nonlinear optics

The Possibility of the application of the finite element method to some problems of nonlinear optics is investigated in this paper. The self-action of a light beam in a nonlinear medium is considered. The general approach to the cretion of conservative computation schemes is presented, based on varitional principles. Definite schemes, which are applicable for the problem of thermal self-action, are described in detail both in the case of cylindrical and or rectangular co-ordinates. The accuracy and convergence of the models are analysed. The results of computation of the self-action problems in motionless and moving media are presented.     

Evaluation of reactive ion etching processes for fabrication of integrated GaAs/AlGaAs optoelectronic devices

Reactive ion etching (RIE) was used for the fabrication of GaAs/AlGaAs optoelectronic devices (laser diodes and photodetectors) for optical interconnect applications. Smooth, vertical sidewalls with a smooth surface at the field were obtained after optimizing RIE conditions in BCl₃-formed plasma. Accurate in-situ monitoring of the etching process was realized by laser interferometry end-point detection. This led to good process control and reproducibility of the demanding fabrication of the optoelectronic devices. The RIE etching process did not affect the electrical properties of the device by increasing the surface recombination currents. Lasers with etched mirrors exhibited a threshold current density of 970 A cm⁻², which is one of the best values ever reported. The feasibility of a simple technology for the fabrication of optoelectronic circuits, based on a BCl₃ RIE process for laser mirror etching, has been demonstrated.