Light driven actuators that have already been proposed are intended for applications on a rather small scale, however, commercially available laser oscillators have sufficient energy to drive much larger objects. Is it possible to realize light-driven actuators that can replace electrical motors? In this paper, a discussion regarding this goal is presented basic of the conversion efficiencies from light energy into mechanical energy. Several methods of actuation, including the one that is based on radiation pressure, were compared from this perspective. The energy conversion efficiencies for converting the motion of the actuator element into a useful form of motion are separately considered. It was concluded that light-absorption type actuators with a continuous operation scheme are the most promising for achieving a high efficiency. Based on these findings, a new scheme, called the laser motor, is proposed. In the proposed scheme, a pulsed laser shines on an elastic material and induces a specific form of vibrations in it. By using two lasers of different wavelengths, a traveling wave is formed. Another object is pressed against the vibrating surface and a relative movement between the two objects is then created.

New light-driven actuators based on films of polymer polyvinylidene fluoride are described. The actuators employ the photomechanical bending of the polymer film caused by low power (10 mW and less) laser radiation. The photomechanical effect combines various physical mechanisms, such as anisotropic thermal expansion, converse piezoelectric mechanism along with photovoltaic and pyroelectric ones, while the mechanism of thermal expansion is dominant for slow motion. Mechanical vibrations of the strips of the photomechanical polymer were observed with periodic pulsed laser excitation. The resonance frequency is inversely proportional to the square of the length of the strip, in full agreement with the theory. Resonance frequency measurements were used to determine the modulus of elasticity of the films, which was close to 3.0×10⁹ Pa. Two possible applications were discussed: optical fiber switch and adaptive mirror propelled by the proposed actuators. The actuators have a potential of being used as the components of future light-driven micro/nano systems.

This paper describes the positioning control method of Au-Nafion IPMC. Au-Nafion IPMC can be classified into two types whether the residual strain is generated to the cathode side (SDT) or the anode side (ODT). SDT can be controlled its position by normal integral control. ODT can also be controlled by restricting the maximum changing speed in the integral control. Experimental result showed the close relationship between the direction of the residual strain and the density or the amount of the counter ion.

Optically driven actuators are a non-contact method for the remote application of light energy. We propose a new method for optically driving actuators which uses three polyvinylidine difluoride (PVDF) cantilevers as the legs and a polymer film as the body. The PVDF cantilevers are coated with silver on one surface. PVDF is a ferroelectric polymer that has both pyroelectric and piezoelectric properties. When one side of the cantilever is irradiated by a laser beam, an electric field is produced along cross-section of the cantilever and mechanical displacement occurs by the piezoelectric effect. We measured the response time and the generated force of the cantilever. Optically driven actuator move via the slip-stick effect.

A two-dimensional actuator has a feature of a non-contact for applying light energy remotely. It consists of a magnet as a movement, an acrylic plate and the temperature sensitive ferrite mounted on two-dimensional array on the plate. A curie temperature of the ferrite is set about room temperature. For moving the magnet, two ferrites in the opposite direction are irradiated by the laser. The magnetic force decreases by photo-thermal effect. For generating more strong force, a thickness of the plate and ferrite are optimized by analyzing static magnetic field. As a result, the movement is controlled in the two-dimensional area. Moreover, we attempt to control magnetic levitation.

The mechanical characteristics of polymer materials are of interest to the chemical industry. There are requirements for observation of changes of internal structure to stress. A number of samples under various stress conditions have provided interesting information upon analysis by microscopic birefringence measurement. In the present paper, we propose a birefringence measurement method for observation of the internal structure of polymer materials and analysis of the relationship between a given stress and the corresponding birefringence distribution. The proposed measurement system consists of a He-Ne laser, polarizers, a half-wave plate and a quarter-wave plate. The birefringence distributions of gelatin, such as the phase difference and azimuthal angle, are shown for the case of applied uniaxial and biaxial stress.

This paper proposes a simultaneous measurement technique of 2 displacement components by using a laser beam and one high-speed line CCD camera. The laser beam is divided to two beams. One beam is refl ected by a corner refl ector attached on an object and the refl ected beam is superimposed with the other beam. The superimposed beam is expanded by a microscope objective lens and then passed through both a wedge-shape birefringent plate and a polarizer making a fringe pattern. This pattern has a light intensity distribution like a sinusoidal shape whose envelope curve has one peak. The pattern is captured by the line CCD camera and is used to extract nanometric longitudinal displacement and micrometric lateral displacement measurement.

The MEMS (micro-electro-mechanical systems) microphone enables the manufacturing of small mechanical components on the surface of a silicon wafer. The MEMS microphones are less susceptible to vibration because of the smaller diaphragm mass and an excellent candidate for chip-scale packaging. The PMN-PT materials itself exhibit extremely high piezoelectric coefficients and other desirable properties for an acoustic sensor. In this paper, we present a piezoelectric MEMS microphone based on PMN-PT single crystal diaphragm. The fabrication process including dry etching conditions and scale-factored prototype is presented. In particular, this paper introduces the design of a PMN-PT single crystal diaphragm with interdigitated electrode.

This paper presents the fabrication process of a novel aperture which allows near field optical data storage. We use PMN-PT ((1-x)Pb(Mg_1/3Nb_2/3)O_3-xPbTiO₃) single crystal material - a new generation oxide material known as relaxor ferroelectrics that exhibits extraordinary piezoelectric properties - to fabricate microlenes using photolithography and dry etching techniques. In this paper, we describe the fabrication processes of a PMN-PT single crystal material microlens prototype with a miniature aperture for near field optical data storage. PMN-PT has the merits of transparency for optical usage and also has a high dielectric coefficient that is suitable for actuator and sensor applications. It provides an advantage of manufacturing both aperture and actuator/sensor with the same material. The thermal reflow technique is used to fabricate photoresist microlenses on a freestanding single crystal PMN-PT film as a mask. The PMN-PT lenses are fabricated by a chemically assisted ion beam etching (CAIBE) technique. Finally the focused ion beam (FIB) machining process is used to place a miniature aperture at the apex of the microlens. We were able to successfully fabricate the 10μm PMN-PT microlenses with less than 100nm apertures. From the experimental measurement, we were able to obtain the optical throughput of 1.83x10^-7 from a 50nm aperture.

This paper provides an overview of recent research in the use of microelectromechanical systems (MEMS) actuators for beam steering applications, including optical coherence tomography (OCT). Prototype scanning devices have been fabricated out of polyimide substrates using conventional integrated circuit technology. The devices utilize piezoelectric bimorphs to mechanically actuate the torsion mirror structure made of polyimide. The material properties of the polyimide allow very large scan angles to be realized in the devices while using low voltages. Prototype devices have demonstrated optical scan angles of over 80 degrees with applied voltages of only 40V. Different device sizes have also been demonstrated with resonant frequencies between 15-60Hz (appropriate for real-time imaging). Analytical models have been developed that predict resonant frequency of the device as well as the angular displacement of the mirror. Further finite element modeling (FEM) has been done using ANSYS. These models closely reflect measured scan angles of the prototype devices. Based upon these models, further refinements can be made to the design to produce specific resonant frequencies for use in a multitude of applications. These models are currently being used to design and fabricate multiple devices on a single wafer with minimal post processing requirements. The ability to fabricate these devices in bulk will reduce their cost and potentially make them disposable to reduce the cost of their use in numerous applications, including patient care when used in biomedical imaging applications.

In this paper we report a new design technique to optimize the driving torque of electrostatic side drive micromotors based on a new technique of rotor-poles-shaping. By reshaping the rotor pole from it regular pie shape, we can modify the distributions and directions of electric field in the gap between rotor and stator poles. Hence, the tangential electrostatic force component exerted on the rotor poles, responsible for driving torque, is maximized. A 2D parametric finite element model using ANSYS APDL programming language is developed for the optimization of the rotor pole shape. The finite element model uses a potential periodic boundary condition to simulate only one micromotor sector. Simulation results show an increase of the driving torque up to 48.75%.

Liquid crystal devices are one of the suitable devices for wave-front modulation since its extra low operating voltages such as 1~3Vrms. In this paper, we will present about liquid crystal active prisms for laser beam steering and its characteristics to the temperature change which causes an undesired optical power. Further more, we will present a recent result of a variable focus lens using quantized GRIN lens technology.

Glass is often used as a substrate material for developing microfluidic chips because it is hydrophilic (attracts and holds moisture), chemically inert, stable over time, optically clear, non-porous, and can be fabricated at low cost. However, the size and geometry of the various components, flow channels and fluid reservoirs are all fixed on the substrate material at the time of microfabrication. Recent advances on the development of a light driven microactuator for actively changing the size and geometry of micro features, based on a photo-responsive hydrogel, are described in this paper. Each discrete microactuator in the platform structure is a bi-layered hydrogel that exploits the ionic nature of the pH sensitive polymer blend of polyethylenimine (PEI) and poly(vinyl alcohol) (PVA), and the proton pumping ability of the retinal protein bacteriorhodopsin (bR). When irradiated by a light source with a peak response of 568 nm the bR molecules in the (bR-PVA) layer undergo a complex photocycle that causes protons to be pumped into the adjoining pH sensitive (PEI-PVA) layer. The diffusion of similarly charged ions through the second actuating layer generates electrostatic repulsive and attractive forces which alter the osmotic pressure within the cross-linked polymer network. Depending upon the type of electrostatic forces generated, the pH sensitive hydrogel layer will swell or, alternatively, collapse. The fabrication of the (bR-PVA)-(PEI-PVA) hydrogel microactuator is described and the experimental results from preliminary tests are presented. The application of the light sensitive hydrogels to developing a reconfigurable microchip platform is briefly discussed.

This paper presents a new concept of low degree-of-freedom deformable mirrors. The application of the mirror is the focusing of a laser beam, featuring a variable focal length. The deformation shape, which is in this case a circular parabolic and an elliptical parabolic respectively, is achieved by a local variation of the mirror's thickness. The paper explains the analytical treating of the mirror's thickness distribution as well as an iterative approximation procedure using FEM simulation. The mirrors were fabricated using hot embossing and injection molding technology. The molds required are made from steel whereas the structuring is done by conventional milling. The fabricated mirrors were coated with a reflective gold layer. For deformation measurements a functional demonstrator consisting of the coated mirror, assembly plates and an electromagnetic actuator was produced. The deformation of the mirror was measured using a 3D coordinate measuring machine. The optical function was characterized by a CCD laser measurement setup. Deviation between the measured and the optimal deformation function was sufficiently small. The spot size of the focused laser beam was up to 470 μm whereas the focal length could be varied in a range of 250 mm to 1000 mm. Due to the use of polymeric material, the long time behavior in respect of creep was researched using FEM simulations as well as endurance tests.

In this letter, we proposed a new method for a variable optical attenuator (VOA) through controlling a mechanical misalignment between 2 single mode fibers using a piezoelectric sheet. A piezoelectric sheet with 3 electrodes is adopted in our proposed structure. We can change amount of the bend of the PZT sheet by controlling the applied voltage on the inner electrode of the PZT sheet, which causes the optical loss to be dependent on the applied voltage. The numerical analysis about the optical loss related to the various mechanical offsets is also investigated. From our experimental results, the dynamic range of the proposed structure is about from 0 to 56 dB when the applied voltage range is from 0 to 22V DC. In our previous work using the piezoelectric tube, the dynamic range is about from 0 to 25dB when it is from 0 to 600V DC. The required voltage to get the same attenuation is dramatically reduced. It can make it more practical in the optical communication field.

This paper presents a novel, highly sensitive condenser microphone with a flexure hinge diaphragm. We used the finiteelement analysis (FEA) to evaluate the mechanical and acoustic performance of the condenser microphone with a hinge diaphragm. And we fabricated the miniature condenser microphones with area of 1.5 mm x 1.5 mm. From the simulation and measurement results, we confirmed that the maximum displacements at the center of flexure hinge diaphragms are several hundred times, compared with flat diaphragms. Moreover, the miniature microphones have obtained -3 dB bandwidth of nearly 20 kHz by proper design of the flexure hinge diaphragms.

A liquid pressure varifocus lens has been developed that employs a fibrous actuator which contracts on application of a current or on heating. The focal length of the convex lens can be varied continuously between 90 mm to 300 mm. The shape of the lens changes smoothly and the construction of the lens is extremely simply. It requires a low electric power to drive it. In this study, the optical characteristics and the response time of the liquid pressure varifocus lens were measured. The time constant of the fibrous actuator was 1.0 s for the rise time when electric power was initially supplied. A fibrous actuator having a length of 370 mm was used, and a voltage of 9.5 V was applied.

This paper presents a sol-gel based 1×2 power splitter for an optical communication based on the plastic optical fiber. To find out optimum parameters of a power splitter, mode propagation along the splitter was theoretically analyzed using BPM (Beam Propagation Method) and the results show that the distance between two arms at the output port of a splitter should be kept below 100μm in order to increase the output power. The planar lightwave circuit device was fabricated by a nano imprint lithography process followed by a spin coating process. The core size and the length of a power splitter were 230 μm×230 μm and 2 cm, respectively. The measured surface roughness of core/cladding using the AFM (Atomic Force Microscope) was under 100nm. The characteristics of a fabricated power splitter were conducted using an 850nm VCSEL (Vertical Cavity Surface Emission Laser) source and 50:50 power splitting performance was obtained.

A novel optical manipulation system for controlling three-dimensional positions and rotation of trapped microscopic rods is proposed by using a liquid crystal (LC) device with unique functions such as an anamorphic lens property in addition to both variable-focusing and deflection properties. Arranging the control voltages of the LC optical device, the laser beam can be focused with any elliptical cross section. The trapped slender object is aligned along the rotatable major axis of the elliptically shaped laser beam spot and can be shifted three-dimensionally.

We study on the imaging technology of three-dimensional distribution for sugar chain on single living cell-membrane. This technology can observe the entire cell surface. To observe the cell surface, the local area image of cell-membrane is taken by TIRF (total internal reflection fluorescence) microscopy. And by scanning the whole cell surface area, we can obtain the image of the entire cell membrane. These observed local area images can be converted into an entire surface image by the pattern matching processing. For this scanning technology, we propose the proximal two beam optical tweezers to rotate the single floating cell. This proximal two beam optical tweezers can rotate the floating single cell in the nutrient medium by light pressure. Two beams illuminate the single cell at proximal two points from below and above. The cell is trapped at the center of these two focal points. At the same time, light pressures that are generated at two focal points are made to act as rotational torque. Conventionally TIRF microscope is well known as the observation technology for the cell-membrane using the evanescent light as the exciting light. We can observe the local area images of the fluorescently labeled sugar chain that binds the glycoprotein. Using the proposed optical system, we can obtain the fluorescent distribution images on the cell-membrane.

Pulsed Laser beam irradiation induced nm peak to peak resonant vibrations in solids were generated, detected and analyzed. For the evaluation of the induced vibrations, transducers and optical methods were used. The enhancement effect of vibrational amplitude by resonance and other methods was confirmed. The existence of vibrations of picometer amplitude induced by mechanical means in solids are visualized by use of synchronous illumination and optical manipulation.

An optical actuator has some interesting characteristics, such as no generation of magnetic noise and receiving the energy remotely. A novel micromanipulator by photothermal effect is proposed. It consists of three optical fiber cantilevers. One end of the fiber is cut for a bevel and painted with black color. A photothermal effect is occurred responding to the incident beam at the end of the optical fiber. It can manipulate a sample and move it in the arbitrary place in 3D space. We succeed to fabricate the 3D structures.

Singly-clamped micron-sized cantilevers actuated by optical radiation pressure exerted by a laser are analyzed. An expression for optimum point of actuation giving the maximum amount of deflection is obtained.

Laser manipulation is an important technique suitable for controlling objects in liquid at length scales ranging from sub-micrometers to micrometers. However, the use of this technique by itself is not enough to dexterously or automatically manipulate objects. In this article we propose a concept for automated non-contact micro-manipulation combined with laser manipulation and advanced control system techniques, and describe the configuration of a developed system, i.e. a three-beam laser trapping system with excellent user-interfaces, real-time image processing functions and a micro-laser ablation beam. We also show the results of several demonstrations; namely the arrangement of metallic particles, the manipulation of a non-spherical object, the laser perforation of a cell, and the automated selection and transportation of colored micro beads.

Motion, independent of forces, is described by kinematic parameters (usually using Denavit-Hartenberg convention) that have been used widely in biomechanical fields. Examples of these fields include robotics, human motion studies, and biomechanical structures' design and control; e. g. for exoskeleton and artificial human arm. A common way to precisely measure the joints movements is by using a motion capture system. Until now, the most successful motion capture technology is optical motion capture; this is due to its highly accurate measurement of small reflective markers that are attached to some relevant body landmarks. This paper addresses the problem of estimating the human arm kinematics parameters from video or captured images of human arms. We introduce a new robust framework that leads to reliable and accurate estimation of shoulder and elbow center of rotations along with the arm kinematics parameters.

Proportional control based visual controller is the main method used in the visual serving, but small proportional gain results in the slowly response and large proportional gain will result in large overshoot or make the system instable. A PD visual controller for microassembly system is presented to acquire better dynamic response. The fuzzy logic is applied to tuning the controller gains which is a model free method. Thus, the difficulty in obtaining precise and detailed system model is avoided and we can get satisfactory performance which is robust to modeling error and external disturbances. Furthermore, image moments are selected as visual features to avoid image singularities and the Jacobian matrix is full rank and upper triangular, thus it has the maximal decoupled structure and simplified the controller. A series of simulations are performed on peg and hole assembly to investigate the feasibility and effectiveness of this method.

The scanning start angle (SSA), the scanning angle (SA) and the target slope angle (SA) are important parameters of Linear Array CCD Panoramic Aerial Camera. This paper analyzes the relationship of them and suggests that the current method of calculating SA is very difficult to be realized in engineering. It proposes an algorithm of calculating SSA and SA according to TSA. Its main characteristics are, with achieving the overlap rate as a premise, to calculate SSA and SA reasonably and to try to put the target into the middle of swath coverage, making the coverage as wide as possible. The algorithm is very simple and is easy to be realized in engineering. The paper gives us the relationship graph between TSA and SA.

In this paper, we develop an observation device to measure a 3D position for a moving object by using a laser range finder and a CCD camera. Then, we propose a new method for the object recognition and the tracking control, respectively. As for the recognition, we use a special mark which is called the cross mark. For the tracking control, we construct PID control with an extended Kalman filter to realize control system without delay. Through some experiments, we verify performance of observation device and show availability of our proposed method.

Catheter ablation is the preferred minimally invasive treatment for cardiac arrhythmias. Limited maneuverability of currently available catheters undermines the success of this treatment and subjects operations to prolonged repeated attempts to pace suspicious zones and ablate the arrhythmogenic substrates under ionizing radiation of fluoroscopy. To compensate for such inefficiencies, a control system that can replace operator's hand during the procedure is desired. This system should be able to direct catheter tip toward the ablation site and maintain its contact with the substrate during ablation, accelerating the process and enhancing its precision. To realize such a system, the first step is to kinematically model the catheter and to devise a control strategy to embed the kinematics of the catheter. This paper proposes a simplified approach to model and control a general single-segment active catheter as a continuum robot. In this approach, the flexible catheter is modeled as a rigid manipulator having coupled joints. Utilizing the structural coupling of the catheter, joint-variables are reduced to actuatable parameters thus lifting some of the mathematical difficulties in formulation of a control strategy for redundant manipulators. The modeling is validated through experiments with a typical steerable ablation catheter equipped with an electromagnetic tracker in vitro.

This paper extends the modeling of the effect of fringing field, proposed in our recent work, to more generic devices: electrostatic parallel-plate actuators with deformations. Though these devices can be model as two parallel capacitors with a variable factor depending on the displacement, it is difficult to determine the analytical expression of such a function. It is shown that, like the effect of fringing field, the modeling error of the effective actuator due to deformations can be compensated by introducing a variable serial capacitor. When a suitable robust control is used, the full knowledge of the introduced serial capacitor is not required, but merely its boundaries of variation. Based on this model, a robust control scheme is constructed using the theory of input-to-state stability (ISS) and backstepping state feedback design. This method allows loosening the stringent requirements on modeling accuracy without compromising the performance. The stability and the performance of the system using this control scheme are demonstrated through both stability analysis and numerical simulation.

In this paper a novel method for investigation of inverse scattering in optical complex mediums is proposed. The proposed method is based on Radial Basis Function Neural Networks (RBFNN) and Genetic Algorithms (GAs). Medium discrimination is performed by RBFNN and corresponding medium parameters identification is done using GAs. In the proposed method for simplicity the apodized, chirped and simultaneously apodized and chirped types of mediums are considered as RBFNN library. The proposed method tries to open a new insight to inverse scattering in optical devices and systems identification. The simulated results closely follow full numerical simulations to illustrate the ability of the proposed algorithm.

In this paper an optical transfer function for description of the operation of complex fiber Bragg Gratings similar to electrical ones is presented (H(jω)). For this purpose and reconstruction of the transfer function, the Genetic Algorithm (GA) is used to find optimum number of poles and zeros from the measured reflection coefficient. After building the transfer function according to the developed algorithm in this paper, the reflection coefficient for this approximated system is obtained (simulated) and compared with measured values. The results obtained from the approximated transfer function in these cases are so close to real measured data. So, the presented method introduces an interesting approach for identification of the complex Bragg Gratings in frequency domain. Some of optical characteristics (both frequency domain and time domain parameters) of these systems can be extracted from the approximated transfer function easily.

The Interpolation method for identification of the Apodized and Chirped Fiber Bragg Gratings is used. For this purpose, the Riccati equation for obtaining the reflection coefficient is used and numerically solved. Then for various system parameters, the maximum reflection peaks, bandwidth of the reflection coefficient and the central frequency are determined. Then using interpolation technique, three analytical equations can be extracted for the above-mentioned quantities. Therefore using the obtained reflection coefficient there is a map from the reflection coefficient in frequency domain to real space (index of refraction space). Hence, for the measured reflection coefficient, one can determine the index of refraction profile including Apodized and Chirped functions. The proposed method is effective and can easily determine the index of refraction profile.

In this paper, the effect of carrier tunneling between wells on multiple-quantum well (MQW) laser characteristics is investigated. Based on the rate equations developed for 3-levels (carrier transport between 3-D, 2-D and quasi 2-D states) including carrier tunneling effect, a circuit model is proposed. According to simulation results with change of tunneling time three interesting regions of operation are obtained. The operation of the proposed laser doesn't change for tunneling time larger than a threshold value (0.1 nsec). For the tunneling time smaller than another threshold value (0.01 nsec) the operation of the laser strongly degraded. For the tunneling time between the two thresholds values the operation of the laser can be optimized, which in this paper it is done for obtaining low turn-on delay time, leading to suitable operation from simultaneous filling of the wells, high output intensity and large bandwidth points of view.

An efficient method for high precision displacement measurement based on micro scale ring resonator and MOEMS is presented. The proposed structure can be used as discrete and integrated sensor in engineering applications. Photo-elastic effect is used to convert the physical displacement to the index of refraction variation in the ring resonator array. Analytical relation for description of system transfer function is derived. Single and multiple ring resonators are examined for increase of the system sensitivity. It is shown that an array of multiple ring resonators (array) is better than single ring case. Effects of optical and geometrical parameters of the proposed structure on sensitivity are studied.

In optical and optomechatronics applications including hybrid and integrated cases, there are some inherent phenomena such as dispersion, loss and many others that must be critically removed for performance improvement. Among the others, one of the most quantities is dispersion. Dispersion is important in most optical applications such as optical communications including all accessories and optical sensors. Optical pulse broadening and chirping are main disadvantages of dispersion effect. Dispersion cancellation in these applications is crucial. Dispersion compensators are widely spread with many methods for realization of that. In this paper a novel dispersion compensator and management system based on thermo optical effect is introduced. Thermo optical effect and the index of refraction changes due to temperature in ring resonator are used to manipulate dispersion quantity. Thermal source is generated in this case with application of electrical potential on metallic layer coated on ring resonator. Introduced idea is realized using ring resonators and results are presented.