Lens Research Articles

Analysis of the Problems of the Research and Modernization of Emission Units of Analytical Devices of Vacuum Electronics

In various electron-optical and ion-beam devices and vacuum electronics installations, emission elements and units are used to extract and form beams of charged particles. Their focusing properties significantly affect the quality parameters and technical characteristics of the analytical devices and technological installations in which they are used. Due to the specificity of the initial conditions during the formation of the beams of charged particles in the area of charged particle extraction, the methods of studying single and conventional immersion electron lenses are not suitable for the high quality theoretical and numerical studies of the properties of immersion objectives. In this paper, theoretical and numerical studies were conducted on the problems in analyzing the focusing parameters of charged particles in emission elements and units when solving problems of designing and upgrading devices and installations of vacuum electronics. As a result of the studies, a theoretical method for studying cathode lenses with a curved optical axis was developed and options for solving problems in correcting aberrations of emission elements and units were proposed.

Measuring Lens Focal Length in Lens Characteristics Experiments through Science Process Skills

Abstract This research aims to measure the focal distance of a lens using practical lens properties. The specifications of this practical tool are made from durable acrylic material, light and easy to use. The lens nature practice equipment consists of a light source in the form of an incandescent lamp, lens path, image capture screen, arrow diaphragm, power supply, strong positive lens (+100), weak positive lens (+50) and negative lens (-50). In this practical, the light source, object, lens and screen are placed parallel. Measurements are carried out through scientific process skills including observation, classification, measurement, prediction, communication and drawing conclusions which begin with observing the image produced by the lens using three different object-to-screen distances, namely 40 cm, 60 cm and 80 cm. In addition to determining the focal distance, experiments with positive lenses produce real, inverted and magnified images. Meanwhile, in a negative lens, the image is virtual and upright. In the positive strong lens experiment, the focal distances measured at distances L = 80 cm, 60 cm, and 40 cm respectively produced average focus values of 10.53 cm, 10.49 cm, and 9.95 cm with values The standard error is 0.123 and the R square value is 0.928, indicating a fairly accurate model. In the weak positive lens experiment, the focal distances measured at distances L = 80 cm, 60 cm, and 40 cm respectively produced average values of 4.42 cm, 4.58 cm, and 4.34 cm with standard values The error is 0.0018 and the R square value is 0.9423, indicating a very precise model. In the negative lens experiment, the focal distances measured at distances L = 80 cm, 60 cm, and 40 cm respectively produced average values of 9.57 cm, 9.47 cm, and 8.95 cm with standard error values of 0.08 and an R square value of 0.967, indicating a very strong model in explaining data variations. This is in accordance with the theory of lens properties, namely that converging lenses generally have the ability to form real images, while diverging lenses often produce virtual images

Visual and Refractive Outcomes after Phacoemulsification Cataract Surgery in Nanophthalmic Eyes.

Background/Objectives: The aim of this study was to report the visual and refractive outcomes of nanophthalmic eyes undergoing phacoemulsification at a tertiary cataract center. Methods: This is a prospective consecutive case series. Patients with an axial length of ≤20.5 mm who underwent phacoemulsification at a tertiary cataract center in Hong Kong were included. Eyes undergoing extracapsular cataract extraction or with a previous history of intraocular surgery including trabeculectomy were excluded. The outcome measures were the corrected distance visual acuity (CDVA) and refractive status at four months post-operation. Different intraocular lens formulas were used to compare the refractive outcomes. Results: Out of 22,847 cataract surgeries performed from May 2011 to March 2020, 14 eyes (0.06%) of 10 patients had axial lengths of ≤20.5 mm and underwent phacoemulsification. The mean axial length was 20.13 ± 0.44 mm. Out of these fourteen eyes, three (21%) had postoperative myopic shift with spherical equivalent refraction of more than or equal to 1D compared to the original target. Eleven eyes (79%) had postoperative refraction within 0.5D compared to the original target. Nine out of fourteen eyes (64%) had improvements in postoperative vision. There were no intraoperative complications. When comparing the Hoffer Q, Holladay 1, Holladay 2, Haigis and Hill-RBF 2.0 formulas, there was no significant difference in the absolute errors between the five formulas (p = 0.072). Conclusions: There was no significant difference in the mean absolute errors between the Hoffer Q, Holladay 1, Holladay 2, Haigis and Hill-RBF 2.0 formulas. Myopic shift was not uncommon, and more studies on intraocular lens (IOL) power calculation for short eyes are warranted.

Simulation and experimental analysis of a double-liquid negative lens based on flat electrode

In order to carry out detailed research on focusing of liquid lens in negative optical power with simple structure, a double-liquid negative lens based on flat electrode is proposed. By adjusting voltage applied to indium tin oxide (ITO) conductive glass plates, the interface between glycerol and silicone oil can be changed to tune the focal length. With COMSOL, MATLAB and Zemax softwares, an optical model of the double-liquid negative lens based on flat electrode is established, its focal length at different voltages is simulated and analyzed, and it is found that when the flat exists with a small tilt (1°∼4°), the parallelism of the flat electrode has little influence on the focal length. In addition, through device fabrication and experimental analysis of this double-liquid negative lens, the focal length of the lens changes from -40.21622 mm to -24.2088 mm when operating voltage is 0V-320 V, which is basically consistent with the simulation results. And the maximum resolution of the proposed liquid lens can reach 71.838lp/mm. A lens with negative focal length holds great promise in diverse applications such as endoscopes, holographic imaging and adaptive optics.

Electrically tunable planar liquid-crystal singlets for simultaneous spectrometry and imaging

Conventional hyperspectral cameras cascade lenses and spectrometers to acquire the spectral datacube, which forms the fundamental framework for hyperspectral imaging. However, this cascading framework involves tradeoffs among spectral and imaging performances when the system is driven toward miniaturization. Here, we propose a spectral singlet lens that unifies optical imaging and computational spectrometry functions, enabling the creation of minimalist, miniaturized and high-performance hyperspectral cameras. As a paradigm, we capitalize on planar liquid crystal optics to implement the proposed framework, with each liquid-crystal unit cell acting as both phase modulator and electrically tunable spectral filter. Experiments with various targets show that the resulting millimeter-scale hyperspectral camera exhibits both high spectral fidelity ( > 95%) and high spatial resolutions ( ~1.7 times the diffraction limit). The proposed “two-in-one” framework can resolve the conflicts between spectral and imaging resolutions, which paves a practical pathway for advancing hyperspectral imaging systems toward miniaturization and portable applications.

Effect of Posterior Keratometry and Corneal Radius Ratio on the Accuracy of Intraocular Lens Formulas After Myopic LASIK/PRK.

To investigate the impact of back-to-front corneal radius ratio (B/F ratio) and posterior keratometry (PK) on the accuracy of intraocular lens power calculation formulas in eyes after myopic laser in situ keratomileusis (LASIK)/photorefractive keratectomy (PRK) surgery. A retrospective, consecutive case series study included 101 patients (132 eyes) with cataract after myopic LASIK/PRK. Mean prediction error (PE), mean absolute PE (MAE), median absolute error (MedAE), and the percentage of eyes within ±0.25, ±0.50, and ±1.00 diopters (D) of PE were determined. The Barrett True K-TK formula exhibited the lowest MAE (0.59 D) and MedAE (0.48 D) and the highest percentage of eyes within ±0.50 D of PE (54.55%) in total. In eyes with a B/F ratio of 0.70 or less and PK of -5.70 D or greater, the Potvin-Hill formula displayed the lowest MAE (0.46 to 0.67 D). The Barrett True-TK exhibited the highest prediction accuracy in eyes after myopic LASIK/PRK overall. However, for eyes with a low B/F ratio and flat PK, the Potvin-Hill performed best. [J Refract Surg. 2024;40(9):e635-e644.].

A Multi Comparison of 8 Different Intraocular Lens Biometry Formulae, Including a Machine Learning Thin Lens Formula (MM) and an Inbuilt Anterior Segment Optical Coherence Tomography Ray Tracing Formula.

A comparison of the accuracy of intraocular lens (IOL) power calculation formulae, including SRK/T, HofferQ, Holladay 1, Haigis, MM, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), and AS-OCT ray tracing, was performed. One hundred eyes implanted with either the Rayone EMV RAO200E (Rayner Intraocular Lenses Limited, Worthing, UK) or the Artis Symbiose (Cristalens Industrie, Lannion, France) IOL were included. Biometry was obtained using IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany) and MS-39 AS-OCT (CSO, Firenze, Italy). Mean (MAE) and median (MedAE) absolute errors and percentage of eyes within ±0.25D, ±0.50D, ±0.75D, and ±1.00D of the target were compared, with ±0.75D considered a key metric. The highest percentage within ±0.75D was found with MM (96%) followed by the Haigis (94%) for the enhanced monofocal IOL. SRK/T (94%) had the highest percentage within ±0.75D, followed by Holladay 1, MM, BUII, and ray tracing (all 90%) for the multifocal IOL. No statistically significant difference in MAE was found with both IOLs. EVO showed the lowest MAE for the enhanced monofocal and ray tracing for the multifocal IOL. EVO and ray tracing showed the lowest MedAE for the two respective IOLs. A similar performance with high accuracy across formulae was found. MM and ray tracing appear to have similar accuracy to the well-established formulae and displayed a high percentage of eyes within ±0.75D.

Effect of capsular tension ring implantation on intraocular lens calculation formula selection for long axial myopia

PurposeThe study investigated the effect of capsular tension ring (CTR) implantation on postoperative refractive stability and accuracy of intraocular lens (IOL) formulas for axial length (AL) ≥ 27.0 mm patients.MethodsProspective case series. The eyes of patients underwent phacoemulsification extraction combined with IOL implantation were classified as CTR implantation (A-CTR) and without CTR implantation (B-CON) groups. Refractive outcome and anterior chamber depth (ACD) were recorded at 1 week, 1 month, and 3 months post-operation. Prediction refractive error (PE) and absolute refractive error (AE) of each formula were calculated.ResultsA total of 89 eyes (63 patients) were included and randomized into the CTR (A-CTR) and control groups (B-CON). Comparison of refraction at different postoperative times of the CTR group showed no statistical difference (all P > 0.05). The ACD in the A-CTR group gradually deepened, and that in the B-CON group gradually shallowed (all P > 0.05). The formulas’ AE showed statistically significant differences in CTR and CON groups (P < 0.001). The PE of Hill-RBF 2.0 and EVO formulas in the A-CTR group were more hyperopic than that in the B-CON group (all P > 0.05), the other five formulas were more myopic in A-CTR group than that in the B-CON group (all P > 0.05).ConclusionPatients with 13 mm diameter CTR implantation tended to have stable refraction at 1 week post-surgery and 1 month for those without it. CTR of the 13 mm diameter had no effect on the selection of formulas. Additionally, it is found that Kane and EVO formulas were more accurate for patients with AL ≥ 27.0 mm.

Polyelectrolyte mixture enables electrowetting liquid lens with large optical power tuning range

Electrowetting liquid lenses have aroused considerable interest among researchers in a variety of industrial applications and wetting sciences. However, conventional electrowetting liquid lenses face significant limitations in their optical power tuning range due to contact angle saturation. To address this issue, our research introduces a polyelectrolyte mixture (PM) composed of ammonium polyphosphate and potassium chloride, which enables a broad optical power tuning range for electrowetting liquid lenses. Through a comprehensive analysis involving viscosity, Raman spectrum, and contact angle measurements, we offer additional insights into the interdisciplinary mechanism of the PM in enhancing the electrowetting effect. Our investigation elucidates how the conformation of the polyelectrolyte and the formation of hydrogen bonds at varying concentrations can impact the electrowetting gain. By optimizing the electrowetting concentration of the PM (12.5 wt. % ammonium polyphosphate and 7.5 wt. % potassium chloride), we achieve a liquid lens with an extensive tuning range (−37.97 to +18.71 D) at 0–45 V, featuring a substantial aperture (6.4 mm) and a low threshold voltage (10 V). This PM formulation effectively mitigates contact angle saturation, thereby offering promising applications and paving the way for the development of liquid lenses with a significantly enhanced optical power tuning capacity.

Methyl methacrylate rigid contact lenses doped with N-Vinylpyrrolidone and 3-[Tris(trimethylsiloxy)silyl] propyl methacrylate for improved oxygen permeability

Although soft contact lenses can be adapted to fit different people's eyes, their lack of durability and susceptibility to breakage still exist. The effect of N-vinyl-pyrrolidone (NVP) and 3-[Tris(trimethylsiloxy)silyl] propyl methacrylate (TRIS) on the performance of conventional PMMA rigid contact lenses was investigated in this study. Unlike PMMA rigid contact lenses, we used in-situ copolymerization by introducing the hydrophilic NVP and the silicone-containing monomer TRIS into the molecular chain. We utilized the silicone element in the molecular chain of the copolymer, which has an affinity for oxygen, and the five-membered ring of NVP to allow water molecules to enter the poly(MMA-NVP-TRIS) contact lenses, creating dual channels of a water channel and a silicone channel to transport oxygen. The modified PMMA-based materials were under analysis for their structural, optical, mechanical and transparency features, such as light transmittance, oxygen permeability, and equilibrium water content and so on. Moreover, it was found that the introduction of NVP increased the surface wettability and water content of this material and that the introduction of TRIS increased the oxygen transmission value of this material. In addition, the oxygen transmissibility of poly(MMA-NVP-TRIS) contact lens was twice as high as that of soft commercial contact lenses (CCLs) and we used CCLs as a comparison to evaluate other comprehensive performances visually.

Room-temperature high-power laser emission of erbium-doped fluorite crystals at 2.8 µm.

We report on a high-power continuous-wave (CW) laser at 2.8 µm employing erbium (Er)-doped fluorite crystals as gain materials. With an optimized Er3+ ion concentration, thin "slab" geometry of the sample matching with the tailored pump beam profile and compensated negative thermal lens using a pair of concave mirrors cavity configuration, a highest power of 14.5 W is achieved from a dual-end-pumped Er:CaF2 laser, which, to the best of our knowledge, presents the record power from the room-temperature Er-bulk lasers in the 3-µm spectral range. In addition, 8.05 W output power is obtained from the Er:SrF2 laser with an RMS power stability of 0.35%. This work indicates that Er-doped fluorite crystals with large-scale available fabrication are promising candidates for high-power laser emission at ∼3 µm.

FOV adjustable liquid lens driven by electrowetting effect

In this paper, a FOV (field of view) adjustable liquid lens driven by electrowetting effect is demonstrated. The proposed lens consists of a window glass, a bottom electrode, four sidewall electrodes, two supporting shafts, and a deflectable aperture. The deflectable aperture is nested on the supporting shafts between the two liquids to limit the position of the liquid-liquid (L-L) interface. Different from the conventional FOV adjustable liquid lenses, the proposed lens can realize focal length adjustment and FOV deflection by applying voltages to the four sidewall electrodes, which has a simple structure and a miniaturized drive. The experiment shows that the aperture of the lens is 9 mm, the optical power range is -21 m-1 to -7 m-1 and the tilt angle of the L-L surface is ∼ 18° (± 9°). With a compact structure and easy drive, the proposed lens has great potential for applications in scanning, imaging, and inspection.

Implantation of phakic intraocular lenses in patients with stabilized keratoconus

To date, extensive experience has been accumulated in the correction of high myopia and myopic astigmatism through the implantation of additional negative lenses (phakic intraocular lenses). However, the use of this method in patients with anatomically altered corneas due to keratoconus remains unresolved.Purpose: to assess the effectiveness and safety of correcting high myopia combined with myopic astigmatism by implanting phakic intraocular lenses in patients with stabilized keratoconus at stages 1–2.Materials and methods. The study encompassed results from 27 surgeries involving the implantation of phakic intraocular lenses in patients with high myopia and myopic astigmatism (12.63 ± 4.25 D). These patients had thin corneas and were diagnosed with stage 1–2 keratoconus after undergoing corneal collagen crosslinking treatment – this constituted the main group. The control group comprised 35 surgeries performed on patients with subclinical non-progressive keratoconus (Forme Fruste). All participants underwent evaluations for visual acuity dynamics and refractive stability of spherical and cylindrical components before surgery, immediately post-surgery, and then at 1, 6, and 12 months after implantation. Additional assessments included intraocular pressure measurements, gonioscopy, ultrasonic echobiometry, ultrasonic ophthalmoscopy, biomicroscopy, ophthalmoscopy, endothelial microscopy, vision character and stereopsis determination, ultrasound biomicroscopy, anterior segment optical coherence tomography, electrophysiological studies, and statistical analysis. An IPCL (a type of phakic intraocular lenses made from hydrophilic acrylic) was implanted, capable of correcting myopia up to 30 D and astigmatism up to 10 D.Results. All patients achieved high uncorrected visual acuity 0.86 ± 0.11. Astigmatism correction was successful in 96% of cases. The average postoperative vault – the distance from the back surface of the phakic intraocular lenses to the anterior lens capsule – was 527.5 ± 40.27 μm (range 460–600 μm), and the intraocular pressure was 11.7 ± 2.08 mm Hg. There was a minor decrease in corneal endothelial cell count from 2599 ± 157.3 to 2375 ± 125.3 cells/mm² in the first group and from 2614 ± 104.8 to 2375 ± 43.3 cells/mm² in the second group respectively (p &gt; 0.05), which falls within the acceptable loss range of 4–7% from preoperative values for both groups. Throughout the observation period, there were no cases of cataract development, pigmentary glaucoma, pupillary block, or other vision-threatening complications.Conclusions. Implantation of phakic intraocular lenses in patients with early-stage stabilized keratoconus and subclinical non-progressive keratoconus provides an effective and practically safe means of correcting high myopia and astigmatism.

Widening Multi‐Beam Scan Angle of Conventional Waveguide Lens Antennas by Increasing Focal Points for Multi‐Feed Excitations

AbstractThis paper presents an alternative approach to improve the achievable beam scan angle of a traditional multi‐beam waveguide lens antenna. Due to the focusing mechanism by manipulating the geometrical curvatures of the waveguide lens, the angular scan range is limited in the conventional waveguide lens design using dual‐focal points of excitations because the geometrical curvatures of the waveguide lens only provide two design freedoms. To overcome this limitation, a solution of treating the waveguide lens as a transmit array consisting of non‐identical elements is proposed so that each element of the antenna array can be well calibrated to improve the maximum scan angular range, where a third focus point of excitation can be created by adding another design freedom from the differentiation between non‐identical elements. Each element of this new transmitting array can be well calibrated with the help of a mathematical expression to improve the maximum angular scan range. Numerical simulations show that the proposed antenna architecture exhibits better radiation characteristics than the traditional waveguide lens antenna. Radiation characteristics are studied and compared for both types of lens antennas to validate the design concept. The proposed triple‐focal point provides a higher gain than the traditional lens antenna with fewer antenna elements. The gains of the beams at ±10°, ±20°, ±30°, and ±40° are found to be 27.78, 26.94, 26.19, and 24.04 dBi, respectively. From the comparison, it is seen that the variation in gain by the proposed triple‐focal array design is more stable than the conventional dual‐focal point design.

Quality assessment of the wide-angle detection option planned at the high-intensity/extended Q-range SANS diffractometer KWS-2 combining experiments and McStas simulations.

For a reliable characterization of materials and systems featuring multiple structural levels, a broad length scale from a few ångström to hundreds of nanometres must be analyzed and an extended Q range must be covered in X-ray and neutron scattering experiments. For certain samples or effects, it is advantageous to perform such characterization with a single instrument. Neutrons offer the unique advantage of contrast variation and matching by D-labeling, which is of great value in the characterization of natural or synthetic polymers. Some time-of-flight small-angle neutron scattering (TOF-SANS) instruments at neutron spallation sources can cover an extended Q range by using a broad wavelength band and a multitude of detectors. The detectors are arranged to cover a wide range of scattering angles with a resolution that allows both large-scale morphology and crystalline structure to be resolved simultaneously. However, for such analyses, the SANS instruments at steady-state sources operating in conventional monochromatic pinhole mode rely on additional wide-angle neutron scattering (WANS) detectors. The resolution must be tuned via a system of choppers and a TOF data acquisition option to reliably measure the atomic to mesoscale structures. The KWS-2 SANS diffractometer at Jülich Centre for Neutron Science allows the exploration of a wide Q range using conventional pinhole and lens focusing modes and an adjustable resolution Δλ/λ between 2 and 20%. This is achieved through the use of a versatile mechanical velocity selector combined with a variable slit opening and rotation frequency chopper. The installation of WANS detectors planned on the instrument required a detailed analysis of the quality of the data measured over a wide angular range with variable resolution. This article presents an assessment of the WANS performance by comparison with a McStas [Willendrup, Farhi & Lefmann (2004). Physica B, 350, E735-E737] simulation of ideal experimental conditions at the instrument.

Design of Holographic Condenser Lens for Visible Light Lithography

Photolithography with visible light at λ = 405 nm utilizing the concept of nonlinear saturable absorption effect where the size of the spot is diminished to the nanometer scale as proposed by several researchers is an alluring proposition for cost-effective projection lithography. Costly conventional condenser lenses can be replaced by monochromatic aberration-free and cost-effective volume phase holographic lenses for visible light photolithography with enhanced resolution utilizing the concept of off-axis illumination. However, the diffraction efficiency of holographic lenses depends on the wavelength of illuminating light and the angle of illumination. Angular and spectral characteristics of volume phase holograms can be controlled by optimizing processing parameters. The results on the theoretical optimization of three important processing parameters, namely fringe spacing ( ∧ ), thickness of the film ( d ), and refractive index modulation ( Δ n ) in the light of coupled wave theory for recording holographic lenses of high diffraction efficiency at λ = 405 nm are presented. It is pointed out that a properly designed single holographic lens can be used for off-axis illumination of a photomask with a parallel beam of light, whereas a system of two identical holographic lenses cemented together has to be used to realize a condenser lens similar to a converging lens.

3‐3: Anamorphic‐XR: Imaging Waveguide Technology for Efficient and Wide Field‐of‐View Near‐Eye Display

A near‐eye display technology, Anamorphic‐XRTM, incorporating imaging waveguides is described. Developed for multiple applications since 2011, unique light manipulation capabilities and highly compact form factors are achievable. Catadioptric anamorphic optics and polarisation management are used to sidestep limitations of conventional VR lens and AR waveguide displays, enhancing performance and manufacturability. Simulations and measurements indicate an achievable specification of 90º field‐of‐view at 60ppd; &gt;2000 nits/lumen; 80% polarised light transmission; and &gt;15mm eyebox at 18mm eye relief from a &lt;4mm thick waveguide. A Hybrid Immersive Display is proposed, combining an anamorphic waveguide with a conventional VR display.

International trends in rigid contact lens prescribing (2000–2023): An update

PurposeRigid contact lenses have an important role in contact lens practice. The purpose of this work is to update earlier surveys by describing global trends in rigid lens fitting between 2000-2023. MethodAn annual contact lens prescribing survey was sent to eye care practitioners in up to 71 countries between 2000 and 2023. Data relating to 342,500 fits undertaken in 20 countries returning reliable longitudinal data were analysed in respect of rigid lens fitting, defined as the fitting of any design of a contact lens manufactured in a rigid material. ResultsOverall, rigid lens prescribing increased slightly over time, from 14.2 % of lens fits in 2000 to 15.2 % in 2023 (p < 0.0001). However, post-hoc analysis shows that the change over time is best described as a decline between 2000 and 2012, followed by a steady increase subsequently. There were significant differences in rigid lens prescribing between countries (p < 0.0001). The difference between the percentage of males fitted with rigid lenses, as a proportion of all contact lenses (12.7 %), and females (12.0 %) is significant (p < 0.0001), although not clinically meaningful. Rigid lens wearers are older at fitting than soft lens wearers (38.7 vs 31.3 years, respectively) (p < 0.0001). Analysis of 5,994 rigid lens fits prescribed currently (2019–2023) were categorised as: corneal sphere – 30 %; scleral and corneo-scleral – 28 %; corneal myopia control/orthokeratology – 21 %; and corneal complex (including toric, multifocal and monovision) – 16 %. ConclusionThere has been a slight increase in rigid lens fitting during the second decade of this century. This increase is apparently due to a ‘repurposing’ of rigid lenses, with the growth of scleral/corneo-scleral and myopia control/orthokeratology lens fits essentially replacing conventional spherical corneal lens fits.

Acrylamide‐Based Aramid‐Reinforced Soft Contact Lenses

In this study, manufacturing of acrylamide‐based soft contact lenses is attempted with high elastic modulus, tensile strength, water content, and oxygen transmissibility. For this purpose, colorless and transparent aramids are prepared using diamine monomers with strong electron‐withdrawing groups such as CF3 and sulfone groups. These aramids are used as reinforcing agents. These compounds are not only thermally and thermodynamically stable but also colorless, transparent, and mechanically very robust. They are very soluble in N,N‐dimethylacrylamide. Subsequently, reactive liquid resins are prepared simply by dissolving aramids in N,N‐dimethylacrylamide, and lenses are manufactured by the bulk polymerization of the liquid resins to which an appropriate amount of a crosslinking agent is added. Mechanically enhanced soft contact lenses are thus easily produced by the conventional manufacturing method. Some of the synthesized lenses maintain their original shape without phase separation even after hydration. These lenses have remarkably higher elastic modulus (up to 8.13 MPa) and tensile strength (up to 1.62 MPa) than the conventional lenses made of 2‐hydroxyethyl methacrylate (HEMA). The synthesized lenses also have a high water content (up to 83.0%) and oxygen transmissibility (up to 26.8 Dk t−1).

Experimental demonstration of radius-varying active plasma lensing for laser-plasma-accelerated proton beams with increased collection angle

Active plasma lensing, a compact method for intensifying the focus of charged particle beams by providing a magnetic field gradient of kT/m, has emerged as a sought-after technology in laser plasma accelerator applications. However, the utilization of active plasma lenses faces significant hurdles when dealing with laser-driven proton pulses, characterized by their broad bandwidth and high divergence. To address this challenge, we developed a novel active plasma lens with a variable radius, specifically designed to optimize lens geometry in accordance with the beam envelope, and performed the first measurement of its focusing ability. The experimental findings reveal that, compared to conventional cylindrical active plasma lenses, our radius-varying lens exhibits a 2.0-fold improvement in single-energy transmission efficiency, while maintaining comparable achromatic ability. This breakthrough is anticipated to significantly contribute to the miniaturization of laser proton accelerators. Published by the American Physical Society 2024