We present a new and accurate method to determine the Poisson's ratio of PDMS, using thermal expansion an optical surface profilometer. The Sylgard 184 was found be ν = 0.4950 ± 0.0010 for 182, 0.4974 0.0006. Furthermore, we that both PDMS types, coefficient depends approximately linearly on curing temperature. This can used almost any kind soft polymer cured from liquid at elevated temperatures.

Abstract Diffraction-limited deep focusing into biological tissue is challenging due to aberrations that lead a broadening of the focal spot. The diffraction limit can be restored by employing aberration correction for example with deformable mirror. However, this results in bulky setup required beam folding. We propose bi-actuator adaptive lens simultaneously enables axial scanning and specimen-induced spherical compact setup. Using confocal microscope, we show diffraction-limited up 340 μm...

New therapies, such as cell implants, will in future require teleoperators capable of repeatable positioning accuracy 10 mm and better. This paper describes the design a Stewart platform (hexapod robot system) which can be used for precision microsurgery number different medical disciplines. The system is discussed detail an overview potential applications given. Also, results are reported on application neuroendoscopy.

We present a highly compact and fast varifocal lens with aspherical tunability based on an active piezo-glass-piezo sandwich membrane. Using optimized geometry, improved fabrication compliant elastomer structures together index-matched optical fluid, we achieved outer diameter of just 9 mm (10 packaged) for clear aperture 7.6 mm. The range the focal power was -7 m-1 to +6 m-1, wavefront error around 100 nm response time between 0.1 0.15 ms.

We describe how to recover the quantum numbers of extremal black holes from their near-horizon geometries. This is achieved by constructing gravitational Noether–Wald charges which can be used for non-extremal as well. These are shown equivalent U(1) appropriately dimensionally reduced solutions. Explicit derivations provided ten-dimensional type IIB supergravity and five-dimensional minimal gauged supergravity, with illustrative examples various hole also discuss derive thermodynamic...

In this paper, we present the proof of concept a very fast adaptive glass membrane lens with large aperture/diameter ratio, spherical aberration correction and integrated actuation. The is directly deformed using two piezo actuators that can tune focal length conical parameter. This operating principle allows for usable aperture whole diameter. Together efficient actuation mechanism, around 2/3 total system diameter -- at thickness less than 2mm. response time few milliseconds 12mm aperture,...

In this paper, we compare the performance of 8 PZT ceramics and one PMN-PT material for typical bending actuator applications. This includes measurement nonlinear transverse charge coefficient at high electric field strength related quantities such as Young's modulus, relative permittivity, coercive their temperature dependencies, Curie temperature. Most materials show much higher strains than what is expected from datasheet values. We further study operating region fields against...

We present the first tunable v-shaped mirror, also known as Fresnel that may be used to generate a quasi-nondiffracting line pattern, for example applications in laser lithography or nanomachining with femtosecond lasers. The aperture of device is 5 mm surface flatness better than λ/10, and range tilting angle 1.3–38 mrad, resulting fringe spacing 123 μm down 4.2 red light at 633 nm. In contrast usual cantilever-comb setups, mirrors are supported on PDMS layer tilted by single piezoelectric...

We investigate segmented Bessel beams that are created by placing different ring apertures behind an axicon is illuminated with a plane wave. find analytical estimate to determine the shortest possible beam segment deriving scale-invariant model using appropriate dimensionless parameters such as wavelength and angle. This verified simulations measurements, which in good agreement. The size of was varied from small aperture sizes Frauhofer diffraction limit larger classical limit.

We demonstrate a method for self-sensing of magnetically actuated prism that can be used, e.g., in feedback-loop without the need additional sensors. In order to use impedance actuation coils as measurement parameter, we first obtained optimal frequency is well separated from frequencies and at same time provides best compromise between sensitivity position robustness. then developed combined driver, correlated its output signal mechanical state using defined calibration sequence. reliably...

Using the AdS/CFT correspondence, we study anisotropic charge transport properties of both supersymmetric and nonsupersymmetric matter fields on (2+1)-dimensional defects coupled to a (3+1)-dimensional [Formula: see text] "heat bath." We focus cases finite external background magnetic field, net density mass their combinations. In this context, also discuss limitations due operator mixing that appears in few situations ignore our analysis. At high frequencies, discover spectrum quasiparticle...

We present a varifocal mirror based on piezo-actuated glass membrane that can be used as secondary in miniature Cassegrain-type mirror- or catadioptric objectives. The section has diameter of 10 mm clear 23 mm, with focal range ±8 m-1 and response time the millisecond-scale. two piezo layers enable an aspherical tuning covers elliptic, parabolic hyperbolic regime over most range. demonstrate application simple telefocus objective length 68 at aperture 22 thickness 16.6 mm.

In this paper, we present an analytic model for thickness resonating plate ultrasound energy receivers, which have derived from the piezoelectric and wave equations and, in included dielectric, viscosity acoustic attenuation losses. Afterwards, explore optimal electric load predictions by zero reflection power maximization approaches literature with different boundary conditions, discuss their limitations. To validate our model, compared expressions KLM solved numerically very good...

In this paper we present and verify the non-linear simulation of an aspherical adaptive lens based on a piezo-glass sandwich membrane with combined bending buckling actuation. To predict full piezoelectric behavior, measured charge coefficient, hysteresis creep effects piezo material inserted them into FEM model using virtual electric field. We further included discussed fabrication parameters -- glue layers thermal stress their variations. our simulations, fabricated set lenses different...

We present a new principle for tuning the diffraction efficiency of an optical grating and its implementation in micro-optical device. The overlap two phase gratings is used to vary effective shift hence efficiency. study working using Fourier Optics simulate pattern far field design realize device based on integrated piezo actuation. find good agreement between simulation experiment observe suppression first order intensity by more than 97% response times less 3 ms.

We study the spatial intensity distribution and self-reconstruction of quasi-Bessel beams produced from refractive axicon lenses with edge emitting laser diodes as asymmetric astigmatic illumination sources. Comparing these to a symmetric mono-mode fiber source, we find that asymmetry results in transition beam into bow-tie shaped pattern eventually line profile at larger distance along optical axis. Furthermore, analytically estimate discuss effects astigmatism, substrate modes non-perfect...

The better understanding of the systems human body and their specific functions has led to minimally invasive microsurgical procedures being carried out on an ever smaller scale. New therapies will require precision 10 fim or better, which only be achievable with robotic teleoperators. Experience existing robot-assisted surgery shows that human-machine interface is a critical component for acceptance this technology, but no universally satisfactory yet been found. Therefore, article...

In this paper, we verify the two optimal electric load concepts based on zero reflection condition and power maximization approach for ultrasound energy receivers. We test a high loss 1–3 composite transducer, find that measurements agree very well with predictions of analytic model plate transducers have developed previously. Additionally, also confirm loads are different when losses in receiver high. Finally, compare by KLM models frequency dependent attenuation to evaluate influence viscosity.

We present a compact adaptive glass membrane lens for higher order wavefront correction and axial scanning, driven by integrated segmented piezoelectric actuators. The can be deformed in combination of rotational symmetry providing focus control up to ± 6 m-1 spherical aberration 5 wavelengths different discrete symmetries correct aberrations such as astigmatism, coma trefoil 10 wavelengths. Our design provides large clear aperture 12 mm at an outer diameter the actuator 18 mm, thickness 2...

This paper describes a test prototype for precision robot-assisted surgery using hexapod operating robot and movable cockpit tactile feedback. The objective of the work described is twofold: 1, to evaluate use robots precisely manipulating endoscopes surgical instruments in submillimeter surgery; 2, new user interface concept based on Based principle flight simulator, aim give surgeon motion cues addition endoscope image, assist his spatial orientation. gives detailed description system...