This PDF file contains the front matter associated with SPIE Proceedings Volume 8911, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

The rudimental microparticle contaminants and airborne molecular contaminants (AMCs) will obviously reduce the lifetime of the lens widely used in the high peak power laser system. An inline contaminants sensor based on the optical microfiber (OM) is here proposed. Due to Van Der Waals force and electrostatic attraction, contaminants are easily adhered to the surface of OM, which will cause an obvious perturbation to the evanescent field transmitted in the OM. The additional loss, caused by the adhered contaminants, has been theoretically analyzed and simulated. The corresponding experiments have also been carried out, and the experimental results agree well with the simulation. The inline containments sensor based on OM has potentially wide sensing range for many kinds of determinate absorptive materials.

Methods of generating various illumination patterns remain as an attractive and important micro-optics research area for the development of resolution enhancement in advanced lithography system. In the current illumination system of lithography machine, off-axis illumination is widely used as an effective approach to enhance the resolution and increase the depth of focus (DOF). This paper proposes a novel illumination mode generation unit, which transform conventional mode to double annular shaped radial polarized (DARP) mode for improving the resolution of micro-lithography. Through LightTools^TM software simulation, double annular shaped mode is obtained from the proposed generation unit. The mathematical expressions of the radius variation of inner and outer rings are deduced. The impacts of conventional and dual concentric annular illumination pattern on critical dimension uniformity were simulated on an isolated line, square hole and corner. Lithography performance was compared between DARP illumination mode and corresponding single annular modes under critical dimension of 45nm. As a result, DARP illumination mode can improve the uniformity of aerial image at 45nm node through pitch varied in 300-500 nm to a certain extent.

In this paper, we present a novel method of integrating a microlens array with a multi-channel filter based on Micro-Electro-Mechanical-System (MEMS) technique. The structure has several optical units and every unit can capture the information for a certain band. Therefore, it can be considered as a filtering artificial-compound-eye (ACE). By combining with a CMOS photo-detector, a multi-spectral imaging system was setup. The imaging experimental results prove that the structure can realize color separation and multi-units imaging as expected. Because of its compact structure and good optical property, the novel filtering ACE is suitable to be applied in smart multi-spectral imaging system.

Due to the multiple scattering of light in turbid media such as biological tissues, the image of target becomes highly deteriorated even disappears entirely. The adaptive total variation (ATV) image reconstruction algorithm, which is based on majorization-minimization approach together with Bayesian framework, is utilized to recover the object from its speckle pattern. Numerical simulation results indicates that, compared with Tikhonov regularization method, the ATV approach can effectively suppress the noise of the restored image and preserve more image details as well, consequently greatly boosts the SNR and the sharpness of the result image. Furthermore, the recovered results by ATV algorithm have overcome the diffraction-limit of the conventional optical system. Consequently, the combination of ATV algorithm with multiple scattering of turbid media will be beneficial to the observation of cells and protein molecules in biological tissues and other structures in micro/nano scale.

Perovskite type manganese oxide is a kind of in solid state chemistry and the field of condensed matter physics are used extensively in the study of materials. Application of sol-gel method on perovskite type manganese oxide doping, preparation out series of samples La_0.6Ba_xSr_(0.4-x)MnO₃, including powder and flake. After annealing treatment, the X ray diffraction tests of different annealing temperature on the influence of the structure of the samples was studied.

In the industrial production, as an important transmission part, the screw thread is applied extensively in many automation equipments. The traditional measurement methods of screw thread parameter, including integrated test methods of multiparameters and the single parameter measurement method, belong to contact measurement method. In practical the contact measurement exists some disadvantages, such as relatively high time cost, introducing easily human error and causing thread damage. In this paper, as a new kind of real-time and non-contact measurement method, a screw thread parameter measurement system based on image processing method is developed to accurately measure the outside diameter, inside diameter, pitch diameter, pitch, thread height and other parameters of screw thread. In the system the industrial camera is employed to acquire the image of screw thread, some image processing methods are used to obtain the image profile of screw thread and a mathematics model is established to compute the parameters. The C++Builder 6.0 is employed as the software development platform to realize the image process and computation of screw thread parameters. For verifying the feasibility of the measurement system, some experiments were carried out and the measurement errors were analyzed. The experiment results show the image measurement system satisfies the measurement requirements and suitable for real-time detection of screw thread parameters mentioned above. Comparing with the traditional methods the system based on image processing method has some advantages, such as, non-contact, easy operation, high measuring accuracy, no work piece damage, fast error analysis and so on. In the industrial production, this measurement system can provide an important reference value for development of similar parameter measurement system.

With non-invasive properties and high sensitivities, portable optical biosensors are extremely desirable for point-of-care (POC) applications. Lab-on-a-chip technology such as microfluidics has been treated as an ideal approach to integrate complex sample processing and analysis units with optical detection elements. The work in this paper has developed an integrated dispersive component in combination with a microfluidic chip, providing a portable and inexpensive platform for on-chip spectroscopic sensing. We demonstrate an integrated microfluidic spectroscopic sensor by using an arrayed waveguide grating (AWG) device. In particular, a visible AWG device (λ_c=680nm) with chip size of 12.1mm by 1.5mm was designed and fabricated by employing flamed hydrolysis deposited (FHD) silica as the waveguide material. A straight input waveguide is used to perform device characterization while a perpendicular curved waveguide is employed to introduce laser excitation light. A polymer microfluidic chip is integrated with the AWG device by oxygen plasma bonding. To prove effectiveness of the integrated spectroscopic sensor, fluorescence spectrum of an organic fluorophore (Cy5) was tested. Reconstructed spectrum by using the AWG device is compared with the outcome from a conventional spectrometer and a good consistency is presented.

Tantalum pentoxide film has a huge application potential in microelectronic field owing to its good chemical stability and thermal stability, and its good compatibility with semiconductor integrated circuit. In addition, Tantalum pentoxide film also has a high dielectric constant, a high refractive index, low absorption rate and a wide spectral range from 300nm to 1000nm in the visible spectral region. At present, it has a wide application in antireflection coatings, lasers, optical communication, solar wafers and so on. This review will focus on the preparation methods of Tantalum pentoxide film, and tantalum pentoxide film’s property and application, which are better for us to choose an appropriate method in an appropriate occasion.

We introduce a planar, high focusing ability, low loss lens using subwavelength high contrast grating (HCG). After a plane wave passes through the 21.7μm wide HCG lens, it is focused 9.51μm below the lens, resulting an NA of 75%. At the focal plane, it presents a full-width-half-maximum (FWHM) of 0.95μm, which is extremely close to diffraction limit. The transmittance is 88%, which means that the loss due to reflection and absorption is only 12%. HCG focusing optics is defined by one-step photolithography and thus can be readily integrated with many devices including VCSELs, telescopes, CCDs and solar cells.

Stimulated emission depletion microscopy (STED) has been proved to be a feasible and straightforward method of breaking the conventional diffraction barrier in the far-field. In this paper, we design and setup a home-built high speed STED microscope. Both the excitation beam (488nm) and the depletion beam (592nm) are provided by continuous wave lasers. By using a pair of galvo mirrors (TILL Yanus IV Digital Scan Head), we realize a pixel dwell time down to 2 μs in the experiment which enables an acquisition speed of 2 frames per second in an imaging field of 5*5 μm with an individual pixel size of 10nm. The image acquisition process is controlled by the software Imspector. In the manuscript, we give a clear description on how to build the microscope and also conduct several experiments to evaluate its performance in practice. A spatial resolution of <100nm, which is well beyond the diffraction barrier has been demonstrated in both nanoparticles and biomedical samples. Featuring a superresolution together with a high imaging speed, our STED microscope has big potential to be widely applied in related scientific researches.

Transient x-ray diffraction, also called time-resolved x-ray diffraction and dynamic x-ray diffraction, is one novel diagnostic technique for probing shocked solids. It can provide direct information about microscopic mechanisms governing shock-induced deformation and structural changes at atomistic scales with nanosecond and picoseconds resolution, and lately, it has become possible to measure the structure of transients with sub-picoseconds and sub–Angstrom resolution with the development of ultrafast lasers which can produce femtosecond electron and x-ray pulses in the form of characteristics emission lines as well as x-ray continua in the keV range. In this paper, we detect and measure directly the dynamic response of lithium fluoride single crystal shocked compressed by laser irradiation in SHENGUANG II. In our experiments, high-intensity lasers irradiated a thin Cu foil to generate helium-like rays as x-ray source. Film (IP--image plate) recorded x rays diffracted from multiple lattice planes both perpendicular and oblique angles to the shock loading direction [100]. We gained the diffraction signals of the lattice planes (200) shocked and unshocked, what’s more, other lattices (113), (1-13). The positions of the diffraction lines associated with the (200) lattice plane indicated compression of the lattice along [100] direction by 13%. In the experiment, a large-angle detector consists of two films-one rectangular in shape,one triangular in shape that are positioned to record x rays diffracted from a shocked single crystal nearly within a full π steradian. The experiment shows that transient x-ray diffraction can diagnose the dynamical response of solid with higher resolution.

Project lithography has experienced the development of contact, stepper, and step and scan lithography machine. Currently lithography machine has entered the age of twinscan lithography machine. The twinscan lithography machine took advantages of high efficiency and good compatibility, but the focal depth of twinscan lithography machine was only in the nanometer range. In order to guarantee the quality of the exposure, the twinscan lithography machine put forward high request for detecting the map of the wafer surface. Usually, the uniform sampling method and the whole map rebuilding method were used to detect the map of the silicon wafer surface, which is a main cause for the data redundancy. On the other hand, the map reconstructed by this means was not smooth which caused the motor of lithography machine can't response. To avoid these disadvantages, an algorithm for restoring the wafer surface based on B-spline surface reconstruction is proposed in this paper. This method is able to satisfy requirements for the local adaptive refinement, which effectively avoid data redundancy. This method is robust, which means the effect of solving nonlinear problems and inhibiting fuzzy noise is remarkable. The surface reconstructed by this new method is very smooth, which is more suitable for the movement of the motor in lithography machine.

The conception of memristor is becoming increasingly prevalent due to its remarkable electronic properties. In this paper, a circuit model of the memristor using simple SPICE code is presented. An ideal closed-loop operational amplifier (OP-AMP) is applied to realize the feedback-controlled integrator, which expands the hitherto methods to solve the memristor’s modeling equations presented by HP Lab. The behaviors of the proposed memristor model in SPICE are investigated. The desired excitation source and initial condition of the doped state can both be easily tuned in the memristor model. Different pinched hysteresis loop i-v curves are presented through different stimulus like sinusoidal and square-wave voltage source.

The output signals of the focusing system in lithography are analog. To convert the analog signals into digital ones which are more flexible and stable to process, a desirable data acquisition system is required. The resolution of data acquisition, to some extent, affects the accuracy of focusing. In this article, we first compared performance between the various kinds of analog-to-digital converters (ADC) available on the market at the moment. Combined with the specific requirements (sampling frequency, converting accuracy, numbers of channels etc) and the characteristics (polarization, amplitude range etc) of the analog signals, the model of the ADC to be used as the core chip in our hardware design was determined. On this basis, we chose other chips needed in the hardware circuit that would well match with ADC, then the overall hardware design was obtained. Validation of our data acquisition system was verified through experiments and it can be demonstrated that the system can effectively realize the high resolution conversion of the multi-channel analog signals and give the accurate focusing information in lithography.

The semiconductor industry is aggressively pushed to produce smaller and smaller feature size from their existing base of lithography system, wavefront aberration should be derived by comparing ideal and real wavefronts at the wafer plane of a high resolution lithography system. In modern optical metrology, shearing interferometer is used more and more widely. We proposed a two-dimensional shearing interferometer, using two-dimensional Ronchi grating instead of a traditional one-dimensional grating, which can realize multidirectional and multidimensional shear. In order to further improve the detection accuracy of metrology system, vector diffraction theory is introduced. By comparing the vector and scalar light field, finally we can get the impact of vector light field on the performance of the shearing interferometer. This is for us to further improve the accuracy of detection system to provide rich information, which is crucial for the development of the lithography process.

With the increase of the numerical aperture (NA), the polarization of light affects the imaging quality of projection lens more significantly. On the contrary, according to the mask pattern, the resolution of projection lens can be improved by using the polarized illumination. That is to say, using the corresponding polarized beam (or polarization-mode) along with the off-axis illumination will improve the resolution and the imaging quality of the of projection lens. Therefore, the research on the generation of various polarization modes and its conversion methods become more and more important. In order to realize various polarization modes in polarized illumination system, after read a lot of references, we provide a way that fitting for the illumination system with the wavelength of 193nm.Six polarization-modes and a depolarized mode are probably considered. Wave-plate stack is used to generate linearly polarization-mode, which have a higher degree polarization. In order to generate X-Y and Y-X polarization mode, the equipment consisting of four sectors of λ/2 wave plate was used. We combined 16 sectors of λ/2 wave plate which have different orientations of the “slow” axis to generate radial and azimuthal polarization. Finally, a multi-polarization control device was designed. Using the kind of multi-polarization control device which applying this method could help to choose the polarization modes conveniently and flexibility for the illumination system.

Plasmonic resonances in metallic subwavelength structures have been widely exploited for a broad range of applications including nanoantennas, surface-enhanced Raman spectroscopy, chiral metamaterials, metamagnetism and absorbers. The phenomenon of extraordinary optical transmission (EOT) through subwavelength holes or slits based on the surface plasmon resonance is also extensively studied and has been applied for light harvesting. However, most of work about light harvesting devices suffer from many disadvantages such as narrow operating waveband, sensitive to the polarization state of the incident light, narrow accepting angles at a fixed azimuthal angle, which greatly limit their potential applications to spectroscopic detection and phase imaging. In this work, we present a broadband plasmonic resonant absorber in infrared regime. The plasmonic resonant absorber consists of a three-layer structure, i.e. two-dimensional metallic subwavelength hole arrays/dielectric-spacer/ thick metallic film from top to bottom. The designed plasmonic resonator is found to be polarization insensitive and omnidirectional due to the symmetry of the subwavelength hole array structure. The absorption efficiency of such absorber can be optimized by tuning the geometry of the metallic subwavelength structure and the thickness of the dielectric layer in between the two metallic films. The broadband efficient light absorbing property of the plasmonic resonant absorber can be explained by the synergetic effect of plasmonic resonance and Fabry-Perot (FP) resonance. It is shown that the periodic subwavelength metallic holes interact with the incident light to excite the surface plasmons so that the transmitted light intensity is significantly enhanced. The enhancement of the electric field near the metallic surface leads to an improved absorption. Moreover, FP cavity provides a resonant environment for the excited surface plasmons as well as the diffracted waves. As a result, the efficient light absorbing is achieved over a broad waveband. It should be noted that the proposed absorber can be applied to other working wavebands by carefully tuning the geometry of the metallic subwavelength structure and the thickness of the dielectric layer in between two metallic layers. The designed absorber may find important applications in solar cells, photodetectors, thermo-photovoltaic, and thermal emitters.

The aim of present work is to estimate the impact of gas refractive index shift on the image quality of projection lens caused by the change of environment condition. This work in the paper consists of two parts: a)when temperature rises or reduces, how gas refractive index changes and the wave front error comes up; b)when gas pressure changes. The model objective lens developed for simulation is a US patent lens whose NA <1 and wave front RMS < 5nm in all fields. This paper includes an illustration of the impact of gas refractive index shift on optical system data, wave front, and aberration. According to the analysis, wave front RMS of projection lens will increase about 10nm if the temperature changed by 0.1K or the gas pressure by 100 Pa. Comparing to origin wave front RMS of the patent lens, 5nm, the change caused by gas temperature and pressure can’t be neglected. It proves the necessary of compensating or controlling the optical path change resulted from gas refractive index shift during the lithography projection lens work process.

Micro system currently is the mainstream of application and demand of the field of micro fabrication of civilian and national defense. Compared with the macro assembly, the requirements on location accuracy of the micro-assembly system are much higher. Usually the dimensions of the components of the micro-assembly are mostly between a few microns to several hundred microns. The general assembly precision requires for the sub-micron level. Micro system assembly is the bottleneck of micro fabrication currently. The optical stereo microscope used in the field of micro assembly technology can achieve high-resolution imaging, but the depth of field of the optical imaging system is too small. Thus it’s not conducive to the three-dimensional observation process of the micro-assembly. This paper summarizes the development of micro system assembly at home and abroad firstly. Based on the study of the core features of the technology, a program is proposed which uses wave front coding technology to increase the depth of field of the optical imaging system. In the wave front coding technology, by combining traditional optical design with digital image processing creatively, the depth of field can be greatly increased, moreover, all defocus-related aberrations, such as spherical aberration, chromatic aberration, astigmatism, Ptzvel(field) curvature, distortion, and other defocus induced by the error of assembling and temperature change, can be corrected or minimized. In this paper, based on the study of theory, a set of optical microscopy imaging system is designed. This system is designed and optimized by optical design software CODE V and ZEMAX. At last, the imaging results of the traditional optical stereo microscope and the optical stereo microscope applied wave front coding technology are compared. The results show that: the method has a practical operability and the phase plate obtained by optimized has a good effect on improving the imaging quality and increasing the depth of field.

Compared to conventional optical elements, the binary optical element (BOE) can not only revise aberration, but also reduce optical system’s weight, miniaturize a system and increase the freedom of system design. Nowadays, we need to improve the manufacturing process before the industrialization of the BOE. However, the fabrication accuracy of BOE affects the imaging quality of the optical system. This paper analyzes the influence of fabrication errors on BOE’s diffraction efficiency and transmission wavefront, to guide the processing and tolerance analysis of the optical systems design stage. Generally, in fabrication processes of the multiple-phase step BOE, there are alignment errors, linewidth errors and depth errors for various reasons. Due to the fabrication errors, the diffraction efficiency of the BOE would be reduced, thus stray light is introduced into the system. Besides, BOE graphical structure is also changed, then introduces wavefront aberrations to the optical imaging system, and thereby reduces the imaging quality of the system. Based on scalar diffraction theory, we have come to some conclusions like that the formula of wavefront PTV which can derive the fabrication requirements of alignment accuracy and linewidth accuracy; if 4-step BOE’s linewidth errors are controlled within a certain range, diffraction efficiency declines little, however, when the linewidth errors exceed this range, the diffraction efficiency will decline rapidly; the influence of deep and shallow etching depth errors on the diffraction efficiency is equivalent, the influence of multiple etching depth errors on the diffraction efficiency is independent and symmetric, and so on. This article focuses on analyzing the fabrication requirements of BOE based on how the fabrication errors affect the diffraction efficiency and wavefront imaging quality of BOE, then guide the design and fabrication processes of BOE imaging optical systems.

With the development of science and technology, the demand for high-precision product is increasing continuously. Ultra-smooth surface with sub-nanometer roughness has extensive applications in the field of soft X-ray optics, high power laser and laser gyro. Bowl feed polishing (BFP) technology is an effective ultra-smooth surface processing method, but the polishing process of BFP which is affected by a lot of factors is extremely complex and difficult to control. It is important to understand the effect of the process variables such as abrasive particle size, concentration of abrasive particle, speed of polishing pad, acidity and polishing time in the process of BFP. They are very important parameters that must be carefully formulated to achieve desired material removal rates and surface roughness. Using a design of experiment (DOE) approach, this study was performed investigating the main effect of the each parameter during K9 BFP. A better understanding of the interaction behavior between the various parameters and the effect on removal rate and surface roughness is achieved by using the statistical analysis techniques. In the experimental tests, the optimized parameters combination for BFP which were derived from the statistical analysis could be found for material removal rate and better surface roughness through the above experiment results.

As lithography still pushing toward to lower K₁ imaging, traditional illumination source shapes may perform marginally in resolving complex layouts, freeform source shapes are expected to achieve better image quality. Illumination optimization as one of inverse lithography techniques attempts to synthesize the input source which leads to the desired output wafer pattern by inverting the forward model from mask to wafer. Usually, inverse lithography problem could be solved by standard numerical methods. Recently, a set of gradient-based numerical methods have been developed to solve the mask optimization problem based on Hopkins' approach. In this study, the same method is also applied to resolve the illumination optimization but based on Abbe imaging formulation for partially coherent illumination. Firstly we state a pixel-based source representation, and analyze the constraint condition for source intensity. Secondly, we propose an objective function which includes three aspects: image fidelity, source smoothness and discretization penalty. Image fidelity is to ensure that the image is as close to the given mask as possible. Source smoothness and discretization penalty are to decrease the source complexity. All of the three items could be described mathematically. Thirdly, we describe the detailed optimization flow, and present the advantages of using Abbe imaging formulation as calculation mode of light intensity. Finally, some simulations were done with initial conventional illumination for 90nm isolated, dense and elbow features separately. As a result, we get irregular dipole source shapes for isolated and dense pattern, and irregular quadrupole for elbow pattern. The results also show that our method could provide great improvements in both image fidelity and source complexity.

A design method of diffractive micro-optics elements based on the diffractive integral theory for simulating and representing the turbulent wavefront in infrared wavelength region, and the fabrication technologies mainly consisted of electron beam photolithography and low-cost anisotropic wet etching, are developed in this paper. We simulate the diffraction propagation process according to the Rayleigh-Sommerfeld (RS) diffractive theory or the angular spectrum diffraction theory. The modified Gerchberg-Saxton (GS) algorithm for modeling and simulation so as to easily realize the iterative transmission process from the input plane to the output, which is employed as the design optimization algorithm of diffractive micro-optics elements, is investigated. Several elements are fabricated quickly through a low cost semiconductor technological process. Infrared diffractive optical elements produced by the method are mainly used to form complex far field patterns related with atmospheric flow such as typical turbulence. The elements can transfer common Gaussian beams into desired patterns correspondent to atmospheric turbulence through creating fine phase microstructures with needed size and depth or height over the surface of the elements. The fine surface morphologies of the elements, which originate from the simple planar patterns in photomask and further etched into the wafer, are created by the software based on the phase distribution designed. The diffractive micro-optics elements for generating several typical light field patterns have been fabricated quickly. Experiments show that the method can achieve several special light field simulations. Future work will mainly include a more realistic model for light field generation in atmospheric turbulence.

In this paper, we present a new LC lens with different pattern electrodes including triangle electrode, square electrode, pentagon electrode, hexagon and octagon electrodes. We demonstrate the focusing process of LC lens, when the electrodes are driven by the voltage signal, all the LC lens with different pattern electrodes have good focusing characters along the optical axis. In addition, a LC lens with different sub-electrode pattern is also introduced, the sub-electrodes are designed to circular pattern and each sub-electrode can be driven separately. If the sub-electrodes are driven by the same voltage signal, the LC lens can focus along the axis, while they are controlled separately, it can make the focus swing off the axis over the focal plane. We show the Interference patterns of LC lens with various pattern electrodes. The different focal spot shapes and the optical properties of LC microlens are also demonstrated experimentally.

In cell motility, researchers are usually used fluorescence microscopy, confocal microscopy, or total internal reflection microscopy to track a fluorescent labeled particle and reveal the dynamic trajectory in living. Because all fluorescent dyes have cell toxicity, quantum dots and gold nanoparticles can influence the structures and physical properties of biomolecules which they have labeled, to develop another label-free image approach becomes an important issue. We present here a Fourier-based cross-correlation process to analyze images of adhering living cell, including cell motility and single vesicle trajectory. We treated adhering MG-63 cell with 66 nM Epidermal growth factor (EGF) and observed its dynamic effect on cell motility based on the velocity fields of consecutive cell images. We also used crosscorrelation to track single vesicles in living cells. We found that EGF could rapidly activate the motility of adhering MG- 63 cell, and the vesicle exhibits either directed or diffusive motion.

Computer-generated holograms (CGHs) are commonly used in optical interferometry for producing reference wavefronts with desired shapes. Uncertainties from the computer generated hologram (CGH) manufacturing processes produce errors in the finished hologram and the generated reference wavefront. CGH errors compromise the accuracy of the interferometric measurements. Although errors in the CGHs may be introduced during either the design or the fabrication process, fabrication uncertainties are mostly responsible for the degradation of the quality of CGHs. To specify and verify detection accuracy of aspheric surface testing system, alignment errors and fabrication errors of the CGHs will be analyzed. Methods are discussed for measuring the fabrication errors in the CGH substrate, duty cycle, etching depth, and effect of surface roughness. An example analysis of the wavefront errors from fabrication nonuniformities for a phase CGH is given.

Lithographic equipments are highly complex machines used to manufacture integrated circuits (ICs). To make larger ICs, a larger lens is required, which, however, is prohibitively expensive. The solution to this problem is to expose a chip not in one flash but in a scanning fashion. For step-and-scan lithographic equipment (wafer scanner), the image quality is decided by many factors, in which synchronization of reticle stage and wafer stage during exposure is a key one. In this paper, the principle of reticle stage and wafer stage was analyzed through investigating the structure of scanners, firstly. While scanning, the reticle stage and wafer stage should scan simultaneously at a high speed and the speed ratio is 1:4. Secondly, an iterative learning controller (ILC) for synchronization of reticle stage and wafer stage is presented. In the controller, a master-slave structure is used, with the wafer stage acting as the master, and the reticle stage as the slave. Since the scanning process of scanner is repetitive, ILC is used to improve tracking performance. A simple design procedure is presented which allows design of the ILC system for the reticle stage and wafer stage independently. Finally, performance of the algorithm is illustrated by simulated on the virtual stages (the reticle stage and wafer stage).The results of simulation experiments and theory analyzing demonstrate that using the proposed controller better synchronization performance can be obtained for the reticle stage and wafer stage in scanner. Theory analysis and experiment shows the method is reasonable and efficient.

In this paper, a three-dimensional relaxation method together with a finite difference method (FDM) are used to model the dynamic response behavior of liquid crystal (LC) directors filled into a cavity with complex patterned electrodes. Simulations and analysis have been done for the focus-swing patterned electrodes structures. A new type of LC micro-structure which has an ability to swing its focus over its focal plane has been designed. The simulation shows that the new LC structure designed by us has also a strong ability of swing focus over focal plane. We can expect that the model developed by us can be utilized to design more complex LC microlenses or other functioned LC structures.

Wavefront coding enables conventional optical imaging systems to operate over an extended depth of field/focus by modifying the light field using a specially designed phase mask. Different phase masks can be used to alter the transmitted wavefront of the optical system which may result in different performances in terms of the capability of the depth-of-focus extension, aberration suppression and the process of imaging acquirement. In this paper, we present a comparative study on the performances of two major different categories of the phase mask, i.e., rotational symmetric and asymmetric type phase masks. Three different types of phase masks that are of cubic, quartic, and logarithmic phase profile are investigated. Fabrication and metrology of a cubic mask is conducted and a full cycle of imaging process including the image coding and decoding is performed.

In this paper, metallic back structure with one dimensional periodic nano-ridge is attached to the capping layer of the In_0.53Ga_0.47As photodetector with 100 nm absorption layer. We present finite difference time domain (FDTD) simulation to analyze the optical absorption enhancement of the photodetector. By comparing with the photodetector with planar metallic film, simulation results show that by introducing the nanostructure a 2.8 times and a 3 times absorption enhancements can be achieved under transverse magnetic (TM) and transverse electric (TE) polarized plane wave illuminations, respectively. Increasing the period of the nanostructure, the absorption enhancement peak positions exhibit a red shift. In addition, the optimization of the metal grating height and width is also crucial for maximizing the absorption enhancement. The absorption enhancements are well explained by surface plasmon polaritons and Rayleigh Anomalies phenomena. Solid simulation and theoretical results are both presented with good agreement with each other.

In order to test the high dynamic range error beyond one wavelength after the rough polish process, we design a phase retrieval hybrid algorithm based on diffraction angular spectrum theory. Phase retrieval is a wave front sensing method that uses the intensity distribution to reconstruct the phase distribution of optical field. Phase retrieval is established on the model of diffractive propagation and approach the real intensity distribution gradually. In this paper, we introduce the basic principle and challenges of optical surface measurement using phase retrieval, then discuss the major parts of phase retrieval: diffractive propagation and hybrid algorithm. The angular spectrum theory describes the diffractive propagation in the frequency domain instead of spatial domain, which simplifies the computation greatly. Through the theoretical analysis, the angular spectrum in discrete form is more effective when the high frequency part values less and the diffractive distance isn’t far. The phase retrieval hybrid algorithm derives from modified GS algorithm and conjugate gradient method, aiming to solve the problem of phase wrapping caused by the high dynamic range error. In the algorithm, phase distribution is described by Zernike polynomials and the coefficients of Zernike polynomials are optimized by the hybrid algorithm. Simulation results show that the retrieved phase distribution and real phase distribution are quite contiguous for the high dynamic range error beyond λ.

We propose a stop-band filter in infrared region using a periodically chirped subwavelength structure. The structure is made of a stack of metal and dielectric pattern made on a thick metal layer that is deposited a PMMA substrate. It is found that an appropriately designed microstructure of metal-insulator-metal patches can generate a wideband infrared absorption, resulting in an infrared stop-band filter. Different width of metal-insulator-metal resonator arranged in one unit cell generate trough in the reflection spectrum at different wavelengths. The full width at half magnitude (FWHM) of the stop-band filter can thus be adjusted by tuning the width of the resonators. The larger the range of the resonator width, the wider the bandwidth will be. Under the condition of subwavelength dimension of the structure compared with the working wavelength, it is found that a FWHM of 4μm at central wavelength of ~9μm and a high absorption efficiency of up to 80% can be achieved. The proposed structure provides a novel method in the design of wideband efficient plasmonic absorbers in infrared or THz spectral regions with simultaneously wide bandwidth and high efficiency of absorption.