Double Lens Research Articles

Study of a high precision corneal curvature radius measurement system

In order to improve the measurement efficiency and measurement accuracy of corneal curvature, a high precision corneal curvature radius measurement system was designed. Based on the principle of film reflection imaging, the measurement light source (concentric circle with light-emitting diode lights) is projected onto the cornea of the human eye, and the human eye cornea with the measurement light source marker is imaged on the photodetector by an optical imaging objective lens and processed by the image processing. The height of the measurement light source on the photodetector to the center of the cornea is calculated. Finally, the method of least squares is used to find the corneal curvature radius. The system uses a double telecentric lens for the optical imaging objective lens to ensure that the optical system has a constant magnification in a certain depth of field. At the same time, low coherence interferometry technology is used to accurately measure the distance between the corneal apex and the measuring light source. The standard corneal simulated eye was tested with the designed prototype. The measurement accuracy was ±0.02 mm. The experimental results show that the high accuracy corneal curvature radius measurement system can effectively improve the accuracy of corneal curvature measurement.

Measuring the mutual diffusion coefficient of heavy water in normal water using a double liquid-core cylindrical lens

The mutual diffusion coefficient of heavy water in normal water is measured over a temperature range of 20 to 40 °C using a novel method called the shift of equivalent refractive index slice (SERIS). The measured values range from 1.9086 × 10−5 to 3.0860 × 10−5 cm2/s and fit the Arrhenius equation well, and the calculated data from the equation are consistent with the literature values obtained by the interference method. The SERIS method is based on a double liquid-core cylindrical lens (DLCL); the front liquid core of the DLCL is used as both a liquid diffusion cell and a key imaging lens, and the resolvable minimum of liquid refractive index is δn = 6.15 × 10−5. The rear liquid core is used as an aplanatic lens, and the transversal spherical aberration is less than 1 μm. The SERIS method provides a new way to measure mutual diffusion coefficients of liquid and has the following advantages: visual measurement, use of a simplified device, and easy operation.

Miniature probe for all-optical double gradient-index lenses photoacoustic microscopy.

A novel all-optical double gradient-index (GRIN) lens optical-resolution photoacoustic microscopy (OR-PAM), termed as DGL-PAM, is demonstrated. The miniature probe consists of a single-mode fiber and double GRIN lenses for optical focusing and a miniature fiber Fabry-Perot sensor for ultrasound detection. The new design is simple and realizes high resolution with long working distance (WD) by virtue of the double GRIN lenses. The overall size of the probe is 2.7 mm in diameter. High lateral resolution of 3.7 μm (at 532 nm laser wavelength) and long WD of 5.5 mm are achieved. In vivo OR-PAM of mouse ear demonstrates the imaging ability of DGL-PAM. Since precise alignment of optical and acoustic foci is not needed, the proposed DGL-PAM is relatively easy to implement. It has potential to be developed as a low-cost, disposable OR-PAM probe and for endoscopic applications. The proposed double GRIN lenses for making miniature endoscopic probes can also be applied to other modalities, such as optical coherence tomography and confocal fluorescence microscopy, to enable high resolution and long WD.

Double refraction and spin splitter in normal-conductor/hexagonal-semiconductor junctions

In analogy with light refraction at optical boundary, ballistic electrons also undergo refraction when propagate across a semiconductor junction. Establishing a negative refractive index in conventional optical materials is difficult, but the realization of negative refraction in electronic system is conceptually straightforward, which has been verified in graphene p-n junctions in recent experiments. Here, we propose a model to realize double refraction and double focusing of electric current by a normal-hexagonal semiconductor junction. The double refraction can be either positive or negative, depending on the junction being n-n type or p-n type. Based on the valley-dependent negative refraction, a spin splitter (valley splitter) is designed at the p-n junction system, where the spin-up and spin-down electrons are focused at different regions. These findings may be useful for the engineering of double lenses in electronic system and have underlying application of spin splitter in spintronics.

Aqp0a Regulates Suture Stability in the Zebrafish Lens.

PurposeTo investigate the roles of Aquaporin 0a (Aqp0a) and Aqp0b in zebrafish lens development and transparency.MethodsCRISPR/Cas9 gene editing was used to generate loss-of-function deletions in zebrafish aqp0a and/or aqp0b. Wild type (WT), single mutant, and double mutant lenses were analyzed from embryonic to adult stages. Lens transparency, morphology, and growth were assessed. Immunohistochemistry was used to map protein localization as well as to assess tissue organization and distribution of cell nuclei.Resultsaqp0a−/− and/or aqp0b−/− cause embryonic cataracts with variable penetrance. While lenses of single mutants of either gene recover transparency in juveniles, double mutants consistently form dense cataracts that persist in adults, indicating partially redundant functions. Double mutants also reveal redundant Aqp0 functions in lens growth. The nucleus of WT lenses moves from the anterior pole to the lens center with age. In aqp0a−/− mutants, the nucleus fails to centralize as it does in WT or aqp0b−/− lenses, and in double mutant lenses there is no consistent lens nuclear position. In addition, the anterior sutures of aqp0a−/−, but not aqp0b−/− mutants, are unstable resulting in failure of suture maintenance at older stages and anterior polar opacity.Conclusions. Zebrafish Aqp0s have partially redundant functions, but only Aqp0a promotes suture stability, which directs the lens nucleus to centralize, failure of which results in anterior polar opacity. These studies support the hypothesis that the two Aqp0s subfunctionalized during fish evolution and that Aqp0-dependent maintenance of the anterior suture is essential for lens transparency.

Enhancement of Optical Fiber Coupling Based on Collimated and Focused Laser Diode Beam with Micro Aspherical Plano-Convex Lens Fabricated by Excimer Laser

ABSTRACTIn this article, we have proposed and demonstrated experimentally the double plano-convex micro-aspherical lens scheme to amplify an edge-emitting laser diode (LD) to optical fiber coupler. Both microlenses have two different profiles along their x- and the y-axes direction. The optical simulation software Zemax is used to design and optimize the proposed microlens profile and then fabricate by an excimer laser micromachining system. Focal spot size of LD around 9 µm is achieved experimentally. Light coupling efficiency between LD and optical fiber, using this double plano-convex microlens, is 27.57% and 44.23% for single-mode and multi-mode fiber, respectively.

Effect of standard percutaneous nephroscope combined with bladder soft lens lithotomy in the treatment of serum Hcy, β2MG in kidney stone

Objective To discuss the effect of standard percutaneous nephroscope combined with bladder soft lens lithotomy in the treatment of serum homocysteine (Hcy), beta 2-microglobulin (β2MG) in kidney stone. Methods A total of 100 patients with kidney stone were selected from December 2013 to December 2016 in our hospital, and all patients were randomly divided into double lens and renal lens group, 50 cases in each group, renal lens group was given standard percutaneous nephrolithotomy (PCNL) treatment, the double lens group was given standard percutaneous nephroscope combined with bladder soft lens lithotomy treatment. Intraoperative blood loss, operation, bowel function recovery, length of hospital stay, the issue of stone removal, complications and pain before and after treatment, serum Hcy, β2MG levels were statistical analyzed. Results The intraoperative blood loss, bowel function recovery, length of hospital stay, the incidence of complication of double lens group were significantly lower than thosed of renal lens group, the first phase stone clearance rate, operation time of the former were significantly higher than those of the latter, the differences were statistically significant (P<0.05). The 1, 4 d after treatment, VAS scores, serum Hcy levels of double lens and renal lens group compared with before treatment were increased, the serum β2MG level was increased, but the change of former was significantly more than that of the latter, the difference was statistically significant (P<0.05). Conclusions Standard percutaneous nephroscope combined with bl- adder soft lens lithotomy can improve the treatment of patients with kidney stones and reduce complications and surgical trauma, and it can improve the level of serum Hcy, β2MG, it is beneficial to patients' pain relief, recovery, but it still need to improve the relevant operation technology. Key words: Kidney Calculi; Nephrostomy, Percutaneous; Cystoscopes; beta 2-Microglobulin

NMR at pressures up to 90 GPa

The past 15 years have seen an astonishing increase in Nuclear Magnetic Resonance (NMR) sensitivity and accessible pressure range in high-pressure NMR experiments, owing to a series of new developments of NMR spectroscopy applied to the diamond anvil cell (DAC). Recently, with the application of electro-magnetic lenses, so-called Lenz lenses, in toroidal diamond indenter cells, pressures of up to 72 GPa with NMR spin sensitivities of about 1012 spin/Hz1/2 has been achieved. Here, we describe the implementation of a refined NMR resonator structure using a pair of double stage Lenz lenses driven by a Helmholtz coil within a standard DAC, allowing to measure sample volumes as small as 100 pl prior to compression. With this set-up, pressures close to 100 GPa could be realised repeatedly, with enhanced spin sensitivities of about 5 × 1011 spin/Hz1/2. The manufacturing and handling of these new NMR-DACs is relatively easy and straightforward, which will allow for further applications in physics, chemistry, or biochemistry.

Galactic optical cloaking of visible baryonic matter

Three-dimensional gravitational cloaking is known to require exotic matter and energy sources, which makes it arguably physically unrealizable. On the other hand, typical astronomical observations are performed using one-dimensional paraxial line of sight geometries. We demonstrate that unidirectional line of sight gravitational cloaking does not require exotic matter, and it may occur in multiple natural astronomical scenarios which involve gravitational lensing. In particular, recently discovered double gravitational lens SDSSJ0946+1006 together with the Milky Way appear to form a natural paraxial cloak. A natural question to ask, then, is how much matter in the universe may be hidden from view by such natural gravitational cloaks. It is estimated that the total volume hidden from an observer by gravitational cloaking may reach about 1% of the total volume of the visible universe.

Cooke-Triplet tweezers: more compact, robust, and efficient optical tweezers.

We present a versatile three-lens optical design to improve the overall compactness, efficiency, and robustness for optical tweezers based applications. The design, inspired by the Cooke-Triplet configuration, allows for continuous beam magnifications of 2-10×, and axial as well as lateral focal shifts can be realized without switching lenses or introducing optical aberrations. We quantify the beam quality and trapping stiffness and compare the Cooke-Triplet design with the commonly used double Kepler design through simulations and direct experiments. Optical trapping of 1 and 2μm beads shows that the Cooke-Triplet possesses an equally strong optical trap stiffness compared to the double Kepler lens design but reduces its lens system length by a factor of 2.6. Finally, we demonstrate how a Twyman-Green interferometer integrated in the Cooke-Triplet optical tweezers setup provides a fast and simple method to characterize the wavefront aberrations in the lens system and how it can help in aligning the optical components perfectly.

Focusing error detection based on astigmatic method with a double cylindrical lens group

Abstract Autofocusing and autotracking are widely used in maskless laser lithography, optical imaging, and recording and readout of optical information storage. With the development of optoelectronic techniques, the accuracy of autofocusing and autotracking thus needs to be improved to the nanoscale, and the autotracking range also needs to be extended to tens of micrometers. In this work, an astigmatic method with two cylindrical lenses is proposed, where the focusing error signal is extracted to detect the focusing error. A theoretical analysis and simulation are carried out, accordingly. A focusing error detection system is established to demonstrate the theoretical analysis. The experimental results indicate that the focusing error signal curves present good “S” characteristics. The linear tracking range is up to 18 μ m , and the tracking accuracy is approximately 50 nm. The theoretical and experimental results indicate that the astigmatic method with two cylindrical lenses is a good method for autofocusing and autotracking with both high accuracy and large dynamic range. This work is useful in the fields of high-resolution maskless laser lithography and optical imaging.

Evaluating the applicability of the double system lens model to the analysis of phishing email judgments

Abstract Phishing emails pose a serious threat to cybersecurity. Because human users are the last line of defense, understanding how users identify phishing emails is imperative to addressing this problem. Judgment analysis (JA) provides a means of analyzing both how information in the environment (cues) contributes to an outcome and how users synthesize cues into judgments about that outcome, typically using multiple linear regression. Because JA has not been applied to this domain, this effort assessed if the statistical assumptions of JA with multiple linear regression are upheld. We hypothesized that phishing cues are linearly combinable, meaning a lens model analysis, a type of JA, is appropriate for evaluating phishing judgments. To test this, we analyzed ten participants who judged whether or not emails were phishing using the double system lens model. Results indicated that the lens model is an appropriate means of analyzing phishing judgments, primarily evidenced by the goodness of fits for both the environment model and human judgment models. We also observed varying achievement scores across participants consistent with their varying levels of performance in the judgment task. We discuss our results and how future phishing judgment research can utilize JA afforded analysis capabilities.

The Effect of Coils Area's Ratio and their Separated Distance on the Optical Performance of the Condenser-Objective Magnetic Lens

The work handles the design of an asymmetric double polepiece magnetic lens for the condenser-objective mode having optimum properties through the change of coils area's ratio and their separated distance, which leads to a highest flux density peak of the magnetic field with a lowest spherical aberration coefficient, at the relativistic corrected voltage (Vr=200 kV) and excitation of (NI=10.5 kA-t). The calculation has been made for the magnetic flux lines trajectories and optical properties to limit the defects in the lens and consequently improve the optical performance of the condenser-objective magnetic lens

Anti-Innovation Norms

Intellectual property (IP) scholars have recently turned their attention to social norms-informal rules that emerge from and are enforced by non-hierarchically organized social forces-as a promising way to spur innovation in communities as diverse as the fashion industry and the open source software movement. The narrative that has emerged celebrates social norms' ability to solve IP's free-rider problem without incurring IP's costs. But this account does not fully consider the dark side of social norms. In fact, certain social norms, when over-enforced, can create substantial barriers to the most socially beneficial creative pursuits. Because IP scholars have left unexplored how social can hinder innovation in this way, the harm they cause has gone unmitigated. This Article sheds light on the dark side of innovation norms. It coins the term norms to label these counterproductive social forces. Using the double lens of sociology and psychology, it gives a full theoretical account of three types of anti-innovation norms: research priority, methodology, and evaluation norms-all of which interfere with socially beneficial boundary-crossing innovation. Our elucidation of anti-innovation has both theoretical and policy implications. On the theory side, it suggests that IP scholars to date have been too focused on addressing the free-rider problem. This has caused them to overlook other barriers to innovation, like those posed by the set of anti-innovation we describe here. This focus on free-riding may also help explain why innovation and scholars have paid little attention to debates within the broader literature on law and social concerned with identifying situations in which social are welfare reducing. On the policy side, it points to innovation dilemmas that IP is not fully equipped to solve. While changes to the IP doctrines of attribution and fair use in copyright and nonobviousness in patent law can counteract anti-innovation at the margin, a comprehensive solution requires innovation scholars to broaden their vision beyond the IP toolkit. We take the first steps in this direction, proposing a number of interventions, including novel funding regimes and tax credits.

Efficiency and coherence preservation studies of Be refractive lenses for XFELO application.

Performance tests of parabolic beryllium refractive lenses, considered as X-ray focusing elements in the future X-ray free-electron laser oscillator (XFELO), are reported. Single and double refractive lenses were subject to X-ray tests, which included: surface profile, transmissivity measurements, imaging capabilities and wavefront distortion with grating interferometry. Optical metrology revealed that surface profiles were close to the design specification in terms of the figure and roughness. The transmissivity of the lenses is >94% at 8 keV and >98% at 14.4 and 18 keV. These values are close to the theoretical values of ideal lenses. Images of the bending-magnet source obtained with the lenses were close to the expected ones and did not show any significant distortion. Grating interferometry revealed that the possible wavefront distortions produced by surface and bulk lens imperfections were on the level of ∼λ/60 for 8 keV photons. Thus the Be lenses can be succesfully used as focusing and beam collimating elements in the XFELO.

Metropolitan Innovation and Sustainability in China—A Double Lens Perspective on Regional Development

This study proposes and integrates a double lens investigation framework on sustainability and diversities of innovation at the city level in China. Lens I concerns economic performance with the energy intensiveness of the production mode and Lens II involves a four-dimensional model with the current and potential elements of innovation at the city level. Based on 106Chinese cities data, sample cities grouped in Traditional Regions (TRs), Top Economic Regions (TEs) and New Economy Regions (NEs) of the 9 groups are clarified via the Investigation Lens I, with respect to production power, market openness and energy intensive use. The further research findings through the Investigation Lens II show that there are clear connections between innovation and sustainability and such connections are diversified due to economic reasons but also importantly, due to potential factors of human resource and knowledge creation. Cities in TEs group and especially NEs group in China are important on innovation and sustainability while southern cities in China are more innovative, with a higher potentiality of economic growth than cities in northern China. Industrial tradition and business culture can be one of the key factors influencing local innovation and sustainability.

Double freeform illumination design for prescribed wavefronts and irradiances.

A mathematical model in terms of partial differential equations (PDE) for the calculation of double freeform surfaces for irradiance and phase control with predefined input and output wavefronts is presented. It extends the results of Bösel and Gross [J. Opt. Soc. Am. A34, 1490 (2017)JOAOD60740-323210.1364/JOSAA.34.001490] for the illumination design of single freeform surfaces for zero-étendue light sources to double freeform lenses and mirrors. The PDE model thereby overcomes the restriction to paraxiality or the requirement of at least one planar wavefront of the current design models in the literature. In contrast with the single freeform illumination design, the PDE system does not reduce to a Monge-Ampère type equation for the unknown freeform surfaces, if nonplanar input and output wavefronts are assumed. Additionally, a numerical solving strategy for the PDE model is presented. To show its efficiency, the algorithm is applied to the design of a double freeform mirror system and double freeform lens system.

用双液芯柱透镜测量蔗糖水溶液的液相扩散系数

Based on the consideration of the high resolution of the spatial resolution of the refractive index of the double liquid-core cylindrical lens(DLCL), the liquid-phase diffusion coefficients of different concentrations of aqueous sucrose solution are measured at room temperature(25℃) using two methods. Method 1:equivalent RI(refractive index) method is used to calculate the liquid phase diffusion coefficient by recording the time-dependent change of a specific refractive index layer during diffusion. Method 2:instantaneous diffusion analytical method is used to determine the liquid diffusion coefficient by reading the relationship between image width and diffusion position in an instantaneous diffusion image. The front liquid core of the DLCL serves as a diffusion cell and a main imaging element, and the rear liquid core serves as an aplanatic auxiliary system. The spherical aberration at a particular thin liquid layer can be reduced as needed with a DLCL, and the spherical aberration advantage within a certain range of refractive index can also be reduced. Both methods have the characteristics of high measurement accuracy. The relative errors between the measured results and the literature values of the two methods are less than 1.3% and 3.9%, respectively, indicating that the measurement system is stable and reliable and the measurement results are accurate when the liquid-phase diffusion coefficient is measured with a DLCL.

基于光线追迹的LED裸眼三维显示技术准直性研究

In the integrated imaging naked eye 3D display based on LED, the divergence angle of the pixel point of LED large screen was very large. Flat convex and double convex lens are often employed. The reconstructed light of the image diverges and the pixel crosstalk between adjacent lens units was large, resulting in unclear images during the reproduction of the three-dimensional scene with the reduced imaging quality. The imaging process of integrated imaging based on LED was analyzed according to the principle of ray tracing. The relationship of crosstalk between different shapes of the lens array and adjacent lens units of LED integrated imaging was investigated. A single meniscus lens was used to effectively control the divergence of the reconstructed light. The reconstructed light passing through the lens was more convergent and collimated. The emergent rays through the lens becomes more parallel and the crosstalk between adjacent lens units was reduced effectively. By comparing the simulation result of the letter model, the meniscus lens was more suitable for LED integrated imaging. The imaging effect of the meniscus lens is better than that of the other lens.

Double contact lens-assisted corneal cross-linking in ultrathin corneas with keratoconus

Aims: This study aimed to evaluate the safety and effectiveness of double contact lens-assisted corneal cross-linking (CXL) in keratoconus patients with very thin corneas. Settings and Design: This is a prospective, interventional, nonrandomized, and noncontrolled case series. Subjects and Methods: Twenty eyes of 15 patients with the corneal thinnest point (CTP) <400 μm were included in the study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), Scheimpflug imaging, and endothelial cell loss were evaluated at baseline and at each study visit. After corneal epithelial debridement, ultrasonic pachymetry was used to measure CTP. Double soft contact lenses were applied while riboflavin was instilled every 2 min and ultrasonic pachymetry was repeated. The cornea was then exposed to ultraviolet A light (370 nm, 3 mW/cm2) for 30 min. Riboflavin 0.1% was administered every 2 min during irradiation. Statistical Analysis Used: Statistical evaluation of values at baseline and 6- and 12-month after CXL was performed using t-test with SPSS software version 20 (SPSS Inc., Chicago, IL, USA). Results: Following epithelial removal, mean CTP was 271.4 ± 13.7 μm (range: 263–284 μm). After double contact lens placement, mean CTP increased by 196.8 ± 15.4 μm (range: 188–223 μm) for a mean thickness of 467.1 ± 19.4 μm (range: 423–508 μm). No statistically significant differences were observed in maximum keratometry value (Kmax) and posterior elevation 1 year after CXL. Endothelial cell count, CDVA, anterior elevation, and average of simulated keratometry values (Average SimK) as well as the CTP were not significantly different before and 12 months after CXL. No postoperative complications were encountered in any of our patients. Conclusion: Double contact lens-assisted CXL can be effective for stabilizing corneal topography in eyes with advanced keratoconus, including those with corneas that are too thin for traditional CXL. Further controlled studies with a larger sample size are recommended to confirm our findings.