Monolithic Lens Research Articles

Dual-channel aperture-splitting snapshot spectral imaging detection system

The contemporary spectral imaging detection systems commonly employed, such as pushbroom and stare systems, often necessitate motion-based imaging mechanisms such as scanning motors. This reliance on motion renders the imaging process vulnerable to platform vibrations, resulting in intricate post-image correction procedures and precluding dynamic target detection. Consequently, the advent of snapshot spectral imaging detection systems has ensued. Currently, there are significant challenges in the miniaturization design and rapid data acquisition aspects of snapshot spectral imaging systems. In this study, linear variable filters were employed as spectral components, and, through optical system simulation and design, the design of the nonspherical monolithic lens system and telescope system in the dual-channel aperture-splitting snapshot spectral imaging detection system were separately completed. The spectral range covered 400–1000 nm, with a spectral resolution of 27.3 nm, and each channel had a spatial sampling of 409×409 pixels. Additionally, based on the optical system design results, the system structure design and assembly were completed. Performance testing and preliminary spectral image fusion research were conducted on the assembled prototype. The instrument demonstrated excellent spectral imaging performance, thereby enhancing the efficiency of spectral imaging detection in snapshot spectral imaging.

Monolithically Structured van der Waals Materials for Volume-Polariton Refraction and Focusing.

Polaritons, hybrid light and matter waves, offer a platform for subwavelength on-chip light manipulation. Recent works on planar refraction and focusing of polaritons all rely on heterogeneous components with different refractive indices. A fundamental question, thus, arises whether it is possible to configure two-dimensional monolithic polariton lenses based on a single medium. Here, we design and fabricate a type of monolithic polariton lens by directly sculpting an individual hyperbolic van der Waals crystal. The in-plane polariton focusing through sculptured step-terraces is triggered by geometry-induced symmetry breaking of momentum matching in polariton refractions. We show that the monolithic polariton lenses can be robustly tuned by the rise of van der Waals terraces and their curvatures, achieving a subwavelength focusing resolution down to 10% of the free-space light wavelength. Fusing with transformation optics, monolithic polariton lenses with gradient effective refractive indices, such as Luneburg lenses and Maxwell's fisheye lenses, are expected by sculpting polaritonic structures with gradually varied depths. Our results bear potential in planar subwavelength lenses, integrated optical circuits, and photonic chips.

Beyond the Greco-Roman or Jewish Monocle: Reading Philippians and Paul ‘Kaleidoscopically’

Typically, scholars view/read the enigmatic apostle Paul monolithically—that is, through either a Greco-Roman or Jewish socio-cultural lens. The traditional Lutheran (Greco-Roman/Western) lens was criticized in the mid-/late-twentieth century by scholars highlighting Paul’s Jewishness—resulting in the so-called “New Perspective on Paul” and “Paul within Judaism” movements. This paradigmatic post-Shoah shift of Pauline interpretation begs the questions, “Should we abandon Greco-Roman readings of Paul?” and “Should we continue to read Philippians and Paul through a singular (Jewish) lens?” Building upon the work of Markus Bockmuehl, Abraham Malherbe et al., I argue for an “eclectic and pragmatic” approach. I explain how “monocular” (Greco-Roman or Jewish) and even “binocular” (Greco-Roman and Jewish) approaches flatten Paul’s complex thought world and Sitz im Leben as an in-Christ church-planting missionary. The purpose of this study is to read Philippians and Paul “kaleidoscopically”—considering the distinct Romanitas, juxtaposed and colliding cultures, worldviews, and religions that Paul likely encountered in the cosmopolitan colonia of first-century Philippi. This article transcends the Greco-Roman/Jewish debate surrounding Paul—highlighting the literary and archaeological evidence of competing pagan, Jewish, and Pauline Christ cults in first-century Philippi—and thus encouraging scholars to read Philippians and Paul through a “kaleidoscopic” rather than a monolithic lens.

Super-resolution macroscopic imaging via unknown speckle illumination using sparse aperture transmitter

Optical sparse aperture imaging technology has promising applications in the next generation of high-resolution imaging systems, but the phasing errors correction of sparse aperture is an urgent problem to be addressed. In this paper, we propose a blind structured-illumination super-resolution imaging system using a sparse aperture as the transmitter to overcome phasing errors and obtain higher resolution. In our scheme, an unknown pattern is projected onto the object by a sparse aperture system. By translating the unknown pattern, a sequence of modulated raw images is obtained. Based on these low-resolution raw images, the super-resolution object and the unknown illumination pattern are jointly estimated by the Adam algorithm. Here we show, both in the simulation and experiment, the resolution of reconstructions using sparse aperture as transmitter are similar to those using monolithic lens. Furthermore, we validate that the proposed method can protect the reconstruction effect from piston error and widen the tolerance range of tip/tilt error (peak-valley values) up to 0.5λ. At the same time, our proposed system can also alleviate to some extent the problem of mid-frequency modulation transfer function (MTF) attenuation that exists in sparse aperture imaging. Our approach not only simplifies the process of constructing synthetic aperture system, but also provides a novel application for synthetic aperture systems.

Modular robotic manipulator and ground assembly system for on-orbit assembly of space telescopes

In the field of astronomical observation, large space telescopes are key tools for deep space exploration. However, the aperture of space telescopes is limited by the ability to fabricate large monolithic mirrors or lenses and by severe restrictions on the overall volume and mass capacity of the launch vehicle. The use of robots for autonomous assembly while in orbit is a promising option for the deployment of large-aperture space telescopes. In this paper, we describe a modular robotic manipulator that offers high precision and flexibility. A space telescope ground assembly system is then designed, the key components of which are a redundant robotic manipulator and a reconfigurable telescope unit. The ground-based assembly of the space telescope is implemented through a combination of trajectory planning, visual perception, and robotic supple control techniques, validating the ability of the robotic manipulator to automatically assemble modular space telescopes. Finally, the developed robotic manipulator is used to conduct ground assembly demonstration experiments, and the modular space telescope is assembled according to the assembly task plan, accumulating technical experience for future space telescope assembly tasks in orbit.

Hybrid Integration of VCSEL and 3-μm Silicon Waveguide Based on a Monolithic Lens System

We design an optical interface system for vertical coupling between vertical-cavity surface-emitting lasers (VCSELs) and 3-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> silicon waveguides. The system includes a photoresist lens and a total internal reflection mirror, which allows for passive alignment and flip-chip bonding (FCB) of VCSELs. The simulated coupling loss is 0.7 dB, in optimal conditions, which increases to 1 dB when 3- and 20-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> alignment tolerances are considered in lateral and longitudinal directions, respectively. The system is built by post-processing lens and metallic wiring on the backside of a 3-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> silicon photonic platform. After FCB and embedding of the VCSELs, the system performance is characterized, and VCSEL-to-waveguide coupling efficiency of &#x2212;7.5 dB is obtained.

Monolithic topological honeycomb lens for achromatic focusing and imaging

Wavelength dispersion is a universal phenomenon in refractive optics that degrades optical performances. Current mitigation methods are being greatly challenged by the demanding requirements of miniaturization, low aberrations, high throughput, and accurate manufacture. Here, we propose an unconventional monolithic honeycomb-like lens concept with topological degrees of design freedom, capable of near diffraction-limited achromatic performance. To automate the design process, a methodological framework is presented that directly evolves the honeycomb lens from a flat window, instead of a knowledge-based starting geometry. The honeycomb lens performance at the full field of view is remarkably better than either traditional aspheric lenses or commercial cascaded lenses. It also overcomes limitations of flat metalenses, which have extremely small aperture sizes and suffer from multi-order aberrations. This topological honeycomb lens concept may pave the way to inexpensive and compact achromatic optics for focusing and imaging applications in consumer cameras, wearable optics, virtual reality, etc.

Monolithic focus-tunable lens technology enabled by disk-type dielectric-elastomer actuators

We propose a monolithic focus-tunable lens structure based on the dielectric-elastomer actuator (DEA) technology. In our focus-tunable lens, a soft lens and radial in-plane actuator mimicking the ocular focal-tuning mechanism are constructed in a single body of an optimized dielectric-elastomer film. We provide device fabrication methods including elastomer synthesis, structure formation, and packaging process steps. Performance test measurements show 93% focal tunability and 7 ms response time under static and dynamic electrical driving conditions, respectively. These performance characteristics are substantially enhanced from the previous polylithic DEA tunable lens by a factor 1.4 for the focal tunability and a factor 9.4 for the dynamic tuning-speed limit. Therefore, we obtain greatly enhanced focal tuning control in a remarkably simple and compact device structure.

Designing A Video Laryngoscope Imaging System with A 7-mm Blade for Neonatal Patients

In case of ventilation failure while using a resuscitation mask after a newborn infant is pushed from the birth canal, a doctor must perform intubation in the infant as well as other emergency measures to keep the baby alive. However, because of the considerably small mouth area of a newborn or premature infant, doctors are unable to view the glottis entrance, which can lead to a failed intubation or long intubation time, thereby resulting in either a drop in oxygen levels or a rise in the intrathoracic pressure. Although a normal video laryngoscope with a 12-mm metal blade certainly improves this type of difficult intubation, doctors often complain that the depth of field of this laryngoscope is insufficient and the width of the blade is too wide for performing intubation on neonatal patients. Therefore, in this study, we developed a video laryngoscope imaging system with two modules, an ultrathin 7-mm metal blade, and an optical imaging system. The core technology of this system includes a 2.5-mm optical lens and verification of imaging quality. To allow a physician to immediately determine an infant’s airway position and prevent binocular disparity while performing intubation, the optical properties of monolithic lenses were simulated while designing the imaging system, thereby allowing the physician to obtain a clear and undistorted image within the field of view.

Inverse-designed stretchable metalens with tunable focal distance

In this paper, we present an inverse-designed 3D-printed all-dielectric stretchable millimeter wave metalens with a tunable focal distance. A computational inverse-design method is used to design a flat metalens made of disconnected polymer building blocks with complex shapes, as opposed to conventional monolithic lenses. The proposed metalens provides better performance than a conventional Fresnel lens, using lesser amount of material and enabling larger focal distance tunability. The metalens is fabricated using a commercial 3D-printer and attached to a stretchable platform. Measurements and simulations show that the focal distance can be tuned by a factor of 4 with a stretching factor of only 75%, a nearly diffraction-limited focal spot, and with a 70% relative focusing efficiency, defined as the ratio between power focused in the focal spot and power going through the focal plane. The proposed platform can be extended for design and fabrication of multiple electromagnetic devices working from visible to microwave radiation depending on scaling of the devices.

Designing a video laryngoscope imaging system with a 7mm blade for neonatal patients

When a newborn infant has been pushed from the birth canal due to ventilation failure while using a resuscitation mask, the doctor must implement infant intubation and other emergency steps to keep the baby alive. However, due to the excessively small mouth area of a newborn or premature infant, the doctors are unable to view the glottis entrance, which can lead to either a failed intubation or longer intubation time, thereby resulting in either a drop in oxygen levels or a rise in intrathoracic pressure. Although the normal video laryngoscope with a 12mm metal blade certainly improves this type of difficult intubation, nevertheless, doctors often complain that the depth of field (DOF) is insufficient and the width of the blade is too wide when performing intubation on neonatal patients. Therefore, this study aims to develop two modules of infant’s video laryngoscope, an ultra-thin 7mm metal blade and an optical imaging system, the core technology of which includes an optical design of a 2.5mm lens and verifications of imaging quality. In order to allow physicians to determine the infant’s airway position immediately and to avoid the binocular disparity from a physician while giving intubation, this study has simulated the optical properties of monolithic lenses while designing the imaging system, allowing the doctor to have a clearer and undistorted image within the field of view.

Nanoboomerang-based inverse metasurfaces—A promising path towards ultrathin photonic devices for transmission operation

Metasurfaces have revolutionized photonics due to their ability to shape phase fronts as requested and to tune beam directionality using nanoscale metallic or dielectric scatterers. Here we reveal inverse metasurfaces showing superior properties compared to their positive counterparts if transmission mode operation is considered. The key advantage of such slot-type metasurfaces is the strong reduction of light in the parallel-polarization state, making the crossed-polarization, being essential for metasurface operation, dominant and highly visible. In the experiment, we show an up to four times improvement in polarization extinction for the individual metasurface element geometry consisting of deep subwavelength nanoboomerangs with feature sizes of the order of 100 nm. As confirmed by simulations, strong plasmonic hybridization yields two spectrally separated plasmonic resonances, ultimately allowing for the desired phase and scattering engineering in transmission. Due to the design flexibility of inverse metasurfaces, a large number of highly integrated ultra-flat photonic elements can be envisioned, examples of which include monolithic lenses for telecommunications and spectroscopy, beam shaper or generator for particle trapping or acceleration or sophisticated polarization control for microscopy.

Miniature optical planar camera based on a wide-angle metasurface doublet corrected for monochromatic aberrations.

Optical metasurfaces are two-dimensional arrays of nano-scatterers that modify optical wavefronts at subwavelength spatial resolution. They are poised to revolutionize optics by enabling complex low-cost systems where multiple metasurfaces are lithographically stacked and integrated with electronics. For imaging applications, metasurface stacks can perform sophisticated image corrections and can be directly integrated with image sensors. Here we demonstrate this concept with a miniature flat camera integrating a monolithic metasurface lens doublet corrected for monochromatic aberrations, and an image sensor. The doublet lens, which acts as a fisheye photographic objective, has a small f-number of 0.9, an angle-of-view larger than 60° × 60°, and operates at 850 nm wavelength with 70% focusing efficiency. The camera exhibits nearly diffraction-limited image quality, which indicates the potential of this technology in the development of optical systems for microscopy, photography, and computer vision.

Features of using photocurable acrylic composition to create the immersion-formed layer for lenticular lenses

The possibilities of creating a monolithic lenticular lens with an increased focal length capable of forming a view zone of an autostereoscopic image at a distance of at least 3–7 m away from the screen, are studied. At the optimal ratio between the refractometric, viscosity, and chemical parameters of liquid composition, the use of polymerizable photocurable acrylic compositions based on oligourethane acrylates as the immersion medium gives rise to an immersion-formed polymer with optical parameters ensuring the desired focal length of a monolithic lenticular lens.

Common Path Side Viewing Monolithic Ball Lens Probe for Optical Coherence Tomography

1 ; Common path probes are highly desirable for optical coherence tomography as they reduce system complexity and cost by eliminating the need of dispersion compensation and polarization controlling optics. In this work, we demonstrate a monolithic ball lens based, common path, side viewing probe that is suitable for Fourier domain optical coherence tomography. The probe design parameters were simulated in Zemax modeling software and the simulated performance parameters were compared with experimental results. We characterized the performance of the probe by measuring its collection efficiency, resolution, and sensitivity. Our results demonstrated that with a source input power of 25 mW, we could achieve sensitivity of 100.5 dB, which is within 7 dB of the maximum possible sensitivity that could be achieved using a separate reference arm. The axial resolution of the system was found to be 15.6 µm in air and the lateral resolution (full width half maximum) was approximately 49 µm. The probe optics were assembled in a 1 mm diameter hypotube with a 500 µm inner diameter. Images of finger skin acquired using this probe demonstrated clear visualization of the stratum corneum, epidermis, and papillary dermis, along with sweat ducts.

Monolithically Lens-Integrated Photonic Device Arrays for Compact Optical Transceivers

Monolithically lens-integrated surface-emitting distributed-feedback (DFB) laser arrays and p–i–n photodiode arrays were developed. A combination of dry etching and wet chemical etching was used to fabricate a monolithic InP lens. The lens profile within ±10 µm from the lens center was estimated to be parabolic shape, which is ideal for the collimation of a Gaussian beam. A fabricated lens-integrated surface-emitting DFB laser exhibited a circular, narrow far-field pattern with full-width at half maximums of 3.9×3.5°. An efficient direct coupling of the lens-integrated DFB laser to a single-mode fiber with a coupling efficiency of -3 dB was confirmed. A four-channel lens-integrated surface-emitting laser array and a lens-integrated p–i–n photodiode array were used to fabricate a very compact 100 Gbps (25 Gbps × 4 channel) optical transceiver with 14×9 mm2 footprint.

Engineering a gigapixel monocentric multiscale camera

Multiscale designs greatly simplify the large-scale optics needed to realize the resolution of a large aperture. Unlike most monolithic lens systems, multiscale cameras have interdependencies between the optics at various scales. To realize a successful multiscale design, the relationships between microcamera scale and overall camera scale parameters must be understood. Starting with a specification of the multiscale camera, we present a simplified model that allows paraxial optical quantities to be estimated. Based on these quantities, a monocentric objective and a microcamera can be designed. An example of a practical design using spherical glass optics is presented.

Visual acuity at intermediate distances after implantation of different models of intraocular lenses

Aim. To study the rehabilitative effect of treatment of cataracts by implanting trifocal refractive-diffractive soft intraocular lens MIOL-Record 3. Methods. 192 patients (216 eyes) who were operated on for cataract participated in the study. The first (main) group included 63 patients (72 eyes) in whom cataract extraction and implantation of the domestic trifocal refractive-diffractive monolithic (soft) intraocular lens MIOL-Record 3 was performed. The second group included 64 patients (70 eyes) in whom cataract extraction and implantation of the domestic bifocal refractive-diffractive lens MIOL-Accord was performed. The third group consisted of 65 patients (74 eyes) in whom cataract extraction and implantation of the domestic monofocal lens MIOL-2 was performed. Preoperative examination was performed the day before surgery, postoperative - after 7 days, 1, 3, 6 and 12 months. Results. The mean value of visual acuity at a distance of 50 cm without correction in the group of patients with MIOL-Record 3 1 month after surgery was 0.42±0.01 and was significantly higher than such in patients with MIOL-Accord and MIOL-2 - 0.14±0.01 and 0.1±0.001, respectively. A questionnaire survey revealed that in the group with MIOL-Record 3 additional correction with glasses is never used at the intermediate distance in 98.62% of the cases, in groups with MIOL-Accord - in 54.28%, and with MIOL-2 - in 25.68% of cases. Patients with MIOL-Record 3 were completely satisfied with the results of surgery in 70.84% of the cases, and in groups with MIOL-Accord and MIOL-2 - in 54.28, and 27.03% of cases, respectively. Conclusion. The conducted studies have established the best rehabilitative effect of the treatment of cataract during implantation of a trifocal refractive-diffractive intraocular lens MIOL-Record 3.

Durability of Fresnel lenses: A review specific to the concentrating photovoltaic application

The durability of Fresnel lenses used in the concentrating photovoltaic (CPV) application is reviewed from the literature. The examination here primarily concerns monolithic lenses constructed of poly(methyl methacrylate) (PMMA), with supplemental examination of silicone-on-glass (SOG) composite lenses. For PMMA, the review includes the topics of: optical durability (loss of transmittance with age); discoloration (the wavelength-specific loss of transmittance); microcrazing and hazing; fracture and mechanical fatigue; physical aging, creep, shape change, buckling, and warping; and solid erosion. Soiling, or the accumulation of particulate matter, is examined in the following contexts: its magnitude of reduction in transmittance; variation with time, module tilt, and wavelength; the processes of adhesion and accumulation; particle size, distribution, composition, and morphology; and its prevention. Photodegradation and thermal decomposition, mechanisms enabling aging, are examined relative to the CPV-specific environment. Aspects specific to SOG lenses include: solarization of the glass superstrate; corrosion of glass; delamination of the silicone/glass interface; change in focus due to thermal misfit between the laminate layers; and the chemical stability of poly(dimethylsiloxane) (PDMS). Recommendations for future research are provided, based on the most important and the least explored topics.

Power-Scaling of Diamond Microlensed Microchip Semiconductor Disk Lasers

Power-scaling of an optically pumped 1040-nm microlensed microchip semiconductor disk laser is reported, where the monolithic cavity and lens structure is embodied in single-crystal diamond. Low threshold and circularly symmetric single-transverse-mode emission (M2<1.2) at output power up to 180 mW is obtained for a mode-matched device having an integrated output coupler of 9.4-mm radius of curvature and a 300-mum aperture. Multitransverse mode operation above 1 W is also presented.