Fabrication Of Lenses Research Articles

Fabrication and characterization of a biomimetic polarization selective lens

Incorporating optical structures on curved lens surfaces can improve performance, consolidate functions, and create novel, miniaturized devices. Although commonly found in biological systems, patterning of micro- and nano-optical structures on curved surfaces is challenging for conventional methods. Previous works have demonstrated the ability to pattern curved surfaces but have done little to create functioning devices. In this Letter, we describe a novel spray-coating technique coupled with interferometric exposure and dry etching to create near-IR wire-grid polarizers on convex lens surfaces. Experimental measurements show extinction ratios of >40:1 and transmission values of >80%, which are comparable to modeled results of similar polarizers on flat surfaces.

렌즈 성형용 유리탄소 금형의 초정밀연삭

In this study, glassy carbon was ground for lens core of glass mold press. Ultraprecision grinding process was applied for machining of core surfaces. During the process, brittle crack occurred because of hard-brittleness of glassy carbon. Author investigated optimized grinding conditions from the viewpoint of ductile mode grinding. Geometrical undeformed chip thickness was adopted for critical chip thickness that enables crack free surface. Machined cores are utilized for biaspheric glass lens fabrication and surfaces of lens were compared for verification of ground surface.

Citation Analysis of the Contact Lens Field

To identify, analyze, and celebrate the most highly cited articles relating to contact lenses and the leading authors, journals, institutions, and countries associated with these publications. To capture all contact lens articles published since 1900, a search equation targeting specific contact lens-related terms in the titles of articles was derived and entered into "Web of Science." A rank order list of the 1000 most highly cited articles was assembled, each having received at least eight citations. The most prominent articles, authors, journals, institutions, and countries were identified from this list by simple counts. The most highly cited article relating to contact lenses (although cited exclusively in the physical sciences literature) is that of Phillip and Schmidt (J Non Cryst Solids 1984;63:288-92), reporting the application of the sol-gel process for the fabrication of rigid contact lenses. Eight of the top 10 articles ranked according to average number of citations/year relate to contact lens-associated microbial keratitis. Of the top eight authors, six have spent all, or a substantial proportion, of their academic careers in Australia and seven have worked in optometric research environments. Optometry and Vision Science is the leading journal. The top-ranked institution is The University of New South Wales, Sydney, Australia. The United States is the most prominent publishing country in the field, and Australia ranks highest when the numbers of highly cited articles are considered per head of population. This work provides a unique snapshot of significant articles relating to contact lenses.

A single-pixel wireless contact lens display

We present the design, construction and in vivo rabbit testing of a wirelessly powered contact lens display. The display consists of an antenna, a 500 × 500 µm2 silicon power harvesting and radio integrated circuit, metal interconnects, insulation layers and a 750 × 750 µm2 transparent sapphire chip containing a custom-designed micro-light emitting diode with peak emission at 475 nm, all integrated onto a contact lens. The display can be powered wirelessly from ∼1 m in free space and ∼2 cm in vivo on a rabbit. The display was tested on live, anesthetized rabbits with no observed adverse effect. In order to extend display capabilities, design and fabrication of micro-Fresnel lenses on a contact lens are presented to move toward a multipixel display that can be worn in the form of a contact lens. Contact lenses with integrated micro-Fresnel lenses were also tested on live rabbits and showed no adverse effect.

Research on the Optimized Tool-Path Planning of Computer Controlled Optical Surfacing

Computer controlled optical surfacing (CCOS) is widely used in aspheric optical lenses fabrication because of their high convergence rate on surface based on deterministic removal processes since 1963. As an important part of CCOS techniques, reasonable tool-path would increase the polishing speed, decrease the processing time and then improve the efficiency of polishing. Optimized policy combined with improved Prim algorithm is presented in this paper based on the study of the characteristic of aspheric polishing and the tool-paths in common use. The simulated results show that the length of tool-path is reduced so as to decrease the processing time and increase the working efficiency.

Steering Phased Array Antenna Beams to the Horizon Using a Buckyball NIM Lens

In this paper, we present the design, optimization, fabrication, and measurement of a negative index metamaterial (NIM) buckyball shell lens to steer phased array antenna (PAA) beams to the horizon. The conformal mapping technique of transformation optics is utilized in the design process to facilitate with lens fabrication. A new dual polarization unit cell is designed to avoid the issues associated with short cut wires, were a split ring resonator (SRR) and wire design to be used. The lens is measured using an actual PAA and it demonstrates to-the-horizon scanning as designed, although the material loss is high. An improved unit cell design is proposed to reduce several known loss mechanisms. A new lens design methodology using Bezier curves as seed surfaces is also described.

Subwavelength-size solid immersion lens

We report on the fabrication and characterization of nanoscale solid immersion lenses (nano-SILs) with sizes down to a subwavelength range. Submicrometer-scale cylinders fabricated by electron-beam lithography are thermally reflowed to form a spherical shape. Subsequent soft lithography leads to nano-SILs on transparent substrates for optical characterization. The optical characterization is performed using a high-resolution interference microscope with illumination at 642 nm wavelength. The focal spots produced by the nano-SILs show both spot-size reduction and enhanced optical intensity, which are consistent with the immersion effect.

Gel effects on the fabrication of gradient refractive index plastic rods via energy-controlled polymerization

A UV energy-controlled exposure process for the fabrication of gradient refractive index lenses was developed. In the proposed method, a V-shaped gel zone was formed in the reaction tube to prevent the formation of bubbles in the polymer matrix after photo-induced polymerization. Gel effects on the fabrication and properties of GRIN polymer rods were clarified, and the effect of concentrations of diphenyl sulfide, poly(methyl methacrylate) and photoinitiator on the optical properties of the rod lenses were investigated. A convenient method for the fabrication of gradient refractive index (GRIN) lenses via a UV energy-controlled process using a sloped UV lamp is described, and theoretically available equipment similar to the sloped UV-controlled polymerization system is also proposed.

“JEM-EUSO”計画における大型両面平面フレネルレンズの製作

“JEM-EUSO”計画における大型両面平面フレネルレンズの製作

Ultraprecision Mass Fabrication of Aspherical Fresnel Lens by Glass Molding Press

Glass molding press (GMP) was applied to the fabrication of glass aspherical Fresnel lens for high-efficiency mass production. A pair of molds for the Fresnel lens was precisely fabricated on the Nickel Phosphorous (Ni-P) plating layer by the single diamond cutting with multi-axis machining center. A kind of low transition temperature (Tg) glass was heated to several tens degree centigrade above its Tg and compressed between the two molds. In this way, the shape of the mold was replicated to the glass lens surface. The molding process was simulated by finite element method (FEM), and the molding condition was optimized to minimize the residual stress.

Design and measurements of a broadband two-dimensional acoustic lens

We describe the design, fabrication, and measurement of a 2D broadband gradient index acoustic lens in air. The index of refraction is tuned by controlling the dimensions of acoustic metamaterial unit cell inclusions designed through numerical simulations. The lens was fabricated in plastic through rapid prototyping stereolithography, and measurements of the sound field show good agreement with the theoretical lens performance. The broadband performance of the lens is confirmed for frequencies ranging from 1.5 kHz to 4.5 kHz.

Fabrication and Precise Alignment of Electron Lenses in the Microcolumn Using the Laser Diffraction Pattern

The quality of electron lenses and precision of their alignment are very important factors that determine the resolution of the microcolumn. In this work, we have fabricated the quality electron lenses using the semiconductor processing technologies and checked their circular shapes by using the laser diffraction pattern. The observed diffraction pattern by naked eyes was the circular Airy disk and the measured eccentricity of the lens aperture was found to be less than 0.02. We have also made precise alignment of the electron lenses by illuminating the laser beam through the roughly aligned electron lenses and adjusting the electron lenses while monitoring the diffraction pattern formed by the diffracted laser light from the lens apertures. This new method can replace the conventional alignment method where the expensive equipment like the aligner or the STM is required. We have also found the misalignment limit by measuring the e-beam current that came out from the microcolumn.

Design and Fabrication of Fresnel Lens and ZnO Thin-Film Transducer

A four-level Fresnel lens and piezoelectric transducer were fabricated as an ejector using focused ultrasonic energy. The influence of the fabrication parameters on the profile of the focusing lens was investigated. Highly c-axis (002)-oriented ZnO films were successfully deposited on Pt (annealed)/Ti/SiO2/Si substrates under reasonable conditions, such as RF power of 178 W, substrate temperature of 380 °C, deposition pressure of 10 mTorr, and Ar:O2 gas flow ratio of 50%. These conditions were applied and confirmed through investigating the influence of deposition parameters on the properties of ZnO films.

Design and Fabrication of Fresnel Lens and ZnO Thin-Film Transducer

A four-level Fresnel lens and piezoelectric transducer were fabricated as an ejector using focused ultrasonic energy. The influence of the fabrication parameters on the profile of the focusing lens was investigated. Highly c-axis (002)-oriented ZnO films were successfully deposited on Pt (annealed)/Ti/SiO2/Si substrates under reasonable conditions, such as RF power of 178 W, substrate temperature of 380 °C, deposition pressure of 10 mTorr, and Ar:O2 gas flow ratio of 50%. These conditions were applied and confirmed through investigating the influence of deposition parameters on the properties of ZnO films.

Design and Fabrication of the Single Polepiece Magnetic Electron Lens of Truncated Cone Polepiece Shape

Design and Fabrication of the Single Polepiece Magnetic Electron Lens of Truncated Cone Polepiece Shape

Fabrication of binary Fresnel lenses in PMMA by femtosecond laser surface ablation

We report on the fabrication of binary Fresnel lenses by femtosecond laser surface ablation of poly(methyl methacrylate) (PMMA) substrates. Tight focusing of the laser pulses produced a minimum ablated feature size of 600 nm, enabling the creation of lenses with numerical apertures as high as 0.5 and focal lengths ranging from 500 µm to 5 mm. A precise control of the ablation depth allowed the achievement of a 30% focusing efficiency, close to the maximum theoretical value for this kind of lenses.

Three-dimensional surface profiling and optical characterization of liquid microlens using a Shack–Hartmann wave front sensor

We demonstrate three-dimensional (3D) surface profiling of the water-oil interface in a tunable liquid microlens using a Shack-Hartmann wave front sensor. The principles and the optical setup for achieving 3D surface measurements are presented and a hydrogel-actuated liquid lens was measured at different focal lengths. The 3D surface profiles are then used to study the optical properties of the liquid lens. Our method of 3D surface profiling could foster the improvement of liquid lens design and fabrication, including surface treatment and aberration reduction.

Tunable electromagnetically actuated liquid-filled lens

In this paper, one type of tunable liquid-filled lens using electromagnetic actuation method is presented. Besides the simpler configuration and better compatibility with the mainstream process for the liquid-filled lens fabrication advantages, the inherent double-side actuation capability associated with the electromagnetic actuation method can undoubtedly extend the tunable range for focal length. Based on this design configuration, a binocular-like lens structure is successfully developed. It is experimentally demonstrated that using only one actuator, this lens structure can be used to simultaneously achieve clear image of the objects locating at two different distances on one CCD plane at any time during operation.

Electromagnetic non-destructive evaluation using metamaterials

This paper proposes the study and implementation of metamaterials in electromagnetic non-destructive examination; these materials can serve as electromagnetic flux concentrators in the radio frequency range. Thus, the use of new types of metamaterials, namely conical Swiss roll, is proposed. Here, we present a method of extracting the necessary parameters (effective magnetic permeability and the frequency) from the data obtained by measuring network parameters. Due to the fact that conical Swiss rolls can serve as radio frequency flux concentrators, they can be used in the fabrication of electromagnetic lenses, being designed on the basis of Fourier optic principles. As a direct application, carbon fibre reinforced plastic (CFRP) plates with and without delaminations, created by impacts with low energy, were examined by means of electromagnetic transducers with a metamaterial lens. The characteristics of a carbon fibre woven structure become visible and the delaminations are clearly emphasised.

Fabrication of a micro-optical lens using femtosecond laser 3D micromachining for two-photon imaging of bio-tissues

We report, for the first time to our knowledge, on the application of a micro-optical lens fabricated by three-dimensional (3D) femtosecond laser direct writing for two-photon fluorescence imaging of biological tissues. We show that the two-photon fluorescence images of a plant leaf tissue acquired with the micro-optical lens are comparable to that of a 5× objective lens. Our result represents an important step towards the application of micro-optical components fabricated by femtosecond laser micromachining in miniaturized nonlinear fluorescence microscopy applications, such as two-photon endoscopy.