Diffractive Lens Research Articles

Generation of super-resolved optical needle and multifocal array using graphene oxide metalenses

Ultrathin flat metalenses have emerged as promising alternatives to conventional diffractive lenses, offering new possibilities for myriads of miniaturization and interfacial applications. Graphene-based materials can achieve both phase and amplitude modulations simultaneously at a single position due to the modification of the complex refractive index and thickness by laser conversion from graphene oxide into graphene like materials. In this work, we develop graphene oxide metalenses to precisely control phase and amplitude modulations and to achieve a holistic and systematic lens design based on a graphene-based material system. We experimentally validate our strategies via demonstrations of two graphene oxide metalenses: one with an ultra-long (~16<em>λ</em>) optical needle, and the other with axial multifocal spots, at the wavelength of 632.8 nm with a 200 nm thin film. Our proposed graphene oxide metalenses unfold unprecedented opportunities for accurately designing graphene-based ultrathin integratable devices for broad applications.

Comparison of 1550-nm nonablative fractional laser versus 755-nm picosecond laser with diffractive lens array for atrophic facial acne scars in asian skin: A prospective randomized split-face clinical study

Comparison of 1550-nm nonablative fractional laser versus 755-nm picosecond laser with diffractive lens array for atrophic facial acne scars in asian skin: A prospective randomized split-face clinical study

Presbyopia Management with Diffractive Phakic Posterior Chamber IOL

To evaluate safety and refractive efficiency after posterior chamber diffractive implantable phakic contact lens (IPCL) surgery. Aprospective non-randomized case-series study was performed on 54 myopic eyes of 27 patients who had undergone diffractive IPCL surgery. Corneal endothelial cell density (ECD), central corneal thickness (CCT), intra-ocular pressure (IOP), vault, uncorrected distance (UDVA), spherical equivalent (SE) and defocus curve, were all evaluated twelve months after surgery. The presence of cataracts was evaluated by slit-lamp during apostoperative follow-up. Mean age was 47 ± 2.62 years-old. Mean SE decreased, from -5.95 ± 2.56 D in apre-operative stage, to -0.25 ± 0.25 D twelve months after surgery. Achieved UDVA was 20/20 in 24.1% of all cases, 20/25 in 74.1% of them, and 20/32 in all remaining cases. No eyes suffered lost lines of vision. The binocular defocus curve was 0.06 ± 0.05 logMAR for a-3.0 D of defocus; 0.11 ± 0.04 logMAR for a-1.5 D of defocus, and 0.08 ± 0.03 logMAR for a0 D of defocus. Twelve months after surgery, mean ECD had decreased by 1.43 %, whereas mean CCT had increased by 0.06 %, without any significant statistical difference (p = 0.28 and p = 0.93 respectively). No difference (p: 0.86) in the vault was observed at 6 months vs.12 months, as well as between IOP measurements (p = 0.22). There were no non-intra or postoperative complications, and, specifically, no cataracts developed either. Diffractive IPCL was implanted safely. Corneal endothelial CD, CCT, vault, and IOP remained stable twelve months after surgery. Visual acuity for distance, intermediate and near sight were achieved without spectacles.

Chocolate Terahertz Fresnel Lens

Recent enormous development of 3D printing techniques gave the possibility of precise manufacturing of designed optical structures. This paper presents designing, manufacturing and the results obtained for chocolate Fresnel lens. Chocolate, similarly to wax, can be melted and used in the 3D printed form to create a terahertz (THz) optical element. Parameters of the chocolate lens are compared with the one made of wax. In simple applications both materials can be used as a cost-effective alternative for conventional optical materials used for THz range of radiation. Both lenses have been designed and compared for 140 GHz. Full Text: PDF ReferencesM. Naftaly, R.E. Miles, and P.J. Greenslade, "THz transmission in polymer materials — a data library", Joint 32nd International Conference on Infrared and Millimeter Waves and the 15th International Conference on Terahertz Electronics, 819-820 (2007). CrossRef S. Firoozabadi, F. Beltran-Mejia, A. Soltani, D. Jahn, S.F. Busch, J.C. Balzer, and M. Koch, "THz transmission blazed grating made out of paper tissue", 42nd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 1-2 (2017). CrossRef D. Headland, W. Withayachumnankul, M. Webb, H. Ebendorff-Heidepriem, A. Luiten, and D. Abbott, "Analysis of 3D-printed metal for rapid-prototyped reflective terahertz optics", Optics express 24(15), 17384-17396 (2016). CrossRef S.F. Busch, M. Weidenbach, M. Fey, F. Schäfer, T. Probst, and M. Koch, "Optical Properties of 3D Printable Plastics in the THz Regime and their Application for 3D Printed THz Optics", Journal of Infrared, Millimeter, and Terahertz Waves 35(12), 993-997 (2014). CrossRef C. Jördens, and M. Koch, "Detection of foreign bodies in chocolate with pulsed terahertz spectroscopy", Optical Engineering 47(3), 037003 (2008). CrossRef A.D. Squires, E. Constable, and R.A. Lewis, "3D Printed Terahertz Diffraction Gratings And Lenses", Journal of Infrared, Millimeter, and Terahertz Waves 36(1), 72-80 (2015). CrossRef W. D. Furlan, V. Ferrando, J. A. Monsoriu, P. Zagrajek, E. Czerwińska, and M. Szustakowski, "3D printed diffractive terahertz lenses", Optics letters 41(8), 1748-1751 (2016). CrossRef X. Wei, C. Liu, L. Niu, Z. Zhang, K. Wang, Z. Yang, and J. Liu, "Generation of arbitrary order Bessel beams via 3D printed axicons at the terahertz frequency range", Applied optics 54(36), 10641-10649 (2015). CrossRef S. Banerji, and B. Sensale-Rodriguez, "3D-printed diffractive terahertz optical elements through computational design", Micro-and Nanotechnology Sensors, Systems, and Applications XI 10982, 109822X, International Society for Optics and Photonics (2019). CrossRef M. Surma, I. Ducin, P. Zagrajek, and A. Siemion, "Sub-Terahertz Computer Generated Hologram with Two Image Planes", Applied Sciences 9(4), 659 (2019). CrossRef A. Siemion, P. Komorowski, M. Surma, I. Ducin, P. Sobotka, M. Walczakowski, and E. Czerwińska, "Terahertz diffractive structures for compact in-reflection inspection setup", Optics Express 28(1), 715-723 (2020). CrossRef E.R. Brown, J.E. Bjarnason, A.M. Fedor, and T.M. Korter, "On the strong and narrow absorption signature in lactose at 0.53THz", Applied Physics Letters 90(6), 061908 (2007). CrossRef M. Bernier, F. Garet, and J. L. Coutaz, "Determining the Complex Refractive Index of Materials in the Far-Infrared from Terahertz Time-Domain Data", Terahertz Spectroscopy-Cutting Edge Technology, Intech-Open Science (2017). CrossRef E.Hecht, Optics 5th global ed.(Boston, Pearson Education 2017). DirectLink

Focusing properties of the three-component Thue-Morse zone plate

A new family of diffractive lenses, three-component Thue-Morse zone plates, generated with a three-component Thue-Morse sequence is proposed in this paper. The focusing properties and the evolution of transverse diffraction pattern for the proposed zone plates have been analytically investigated both theoretically and experimentally. The results demonstrate that the new kind of zone plates has a remarkable reduction of chromatic aberration compared with other aperiodic zone plates, e.g., Thue-Morse zone plates. The proposed three-component Thue-Morse zone plates will be promising in optical imaging.

Сравнительный анализ зрительных результатов и субъективной удовлетворенности пациентов после имплантации двух моделей трифокальных дифракционных интраокулярных линз

Сравнительный анализ зрительных результатов и субъективной удовлетворенности пациентов после имплантации двух моделей трифокальных дифракционных интраокулярных линз

Versatile Diffractive Flat Optics

Recently, we have shown that allowing the phase in the image plane of a flat lens to be a free parameter enables imaging properties of unprecedented versatility in flat, multilevel diffractive lenses through careful design of different diffractive surfaces. The properties we have shown in such flat lenses include super-achromaticity, extreme depth-of-focus and high numerical aperture. These flat lenses can be easily fabricated using one-step grayscale lithography.

Recent Progress on Ultrathin Metalenses for Flat Optics.

SummaryAs technology advances, electrical devices such as smartphones have become more and more compact, leading to a demand for the continuous miniaturization of optical components. Metalenses, ultrathin flat optical elements composed of metasurfaces consisting of arrays of subwavelength optical antennas, provide a method of meeting those requirements. Moreover, metalenses have many other distinctive advantages including aberration correction, active tunability, and semi-transparency, compared to their conventional refractive and diffractive counterparts. Therefore, over the last decade, great effort has been focused on developing metalenses to investigate and broaden the capabilities of metalenses for integration into future applications. Here, we discuss recent progress on metalenses including their basic design principles and notable characteristics such as aberration correction, tunability, and multifunctionality.

Short-term Visual Outcomes of Trifocal Diffractive Intraocular Lens Implantation in Patients Who Had Retinal Surgery

Short-term Visual Outcomes of Trifocal Diffractive Intraocular Lens Implantation in Patients Who Had Retinal Surgery

Refractive and visual outcomes of two different aspheric monofocal intraocular lenses with differing tinting and spherical aberration values

Purpose: To compare refractive and visual outcomes of two diffractive monofocal intraocular lenses (IOLs) with different tinting and spherical aberration values. Study design: Retrospective case series. Methods: The right eye of consecutive patients who had undergone bilateral implantation of SZ-1 (NIDEK Co. Ltd., Gamagori, Japan) or ZCB00 (Johnson and Johnson Inc. New Brunswick, NJ, USA) IOLs was evaluated. Refractive outcomes, changes in visual acuity, ocular spherical aberration, and changes in photopic and mesopic contrast sensitivity were analyzed. Results: Thirty-three eyes received the SZ-1 IOL (SZ-1 group, while 29 eyes received the ZCB00 IOL (ZCB00 group). The mean preoperative manifest refraction spherical equivalent (MRSE) was −1.48 ± 4.74 D and −0.34 ± 1.50 in the SZ-1 group and ZCB00 group, respectively. At 3 months, the mean MRSE was −0.87 ± 1.08 D and −0.65 ± 0.76, respectively (p=0.25). At 3 months postoperatively, the mean best spectacle-corrected visual acuity was 0.14 ± 0.20 LogMAR and 0.11 ± 0.17 LogMAR, respectively (p=0.67). At the same time point, ocular spherical aberration was statistically significantly different (0.01 ± 0.23 μm vs. −0.51 ± 0.51 μm, respectively; p<0.0001). Postoperatively, the mean photopic and scotopic contrast sensitivity did not differ between the groups (p=0.57). Conclusion: Postoperative refractive outcomes and visual acuity following the implantation of these aspheric IOLs were similar. The different asphericity and yellow tinting of the SZ-1 IOL did not affect postoperative visual performance.

Study on ITO Fresnel Pattern Liquid Crystal Lens

Everyone is getting old and the presbyopia arise. Conventional presbyopia correction lenses include convex lenses and progressive lenses, each of which has advantages and disadvantages. The convex lens is a short focal length lens, which has the advantage of being able to see immediately when looking at the close, but has the disadvantage that the lens is thick, heavy, and the glasses have to be removed when looking at the distance. Progressive Lens is a multifocal lens that can focus from near to far. It is relatively thin compared to convex lenses, but requires an adaptation period of about 1 to 2 months. To solve this problem, we developed light, thin, and variable refractive index ITO Fresnel pattern lenses using liquid crystals.[1] ITO Fresnel patterns were formed by photo lithography, and the voltages were applied differently for each pattern to drive the liquid crystals, and the focal length was changed as the applied voltage changed. The diopter (D) of the lens has changed over 9V, and showed the maximum diopter of 1 at 13V.[1] Li, Guoqiang, et al. "Switchable electro-optic diffractive lens with high efficiency for ophthalmic applications." Proceedings of the National Academy of Sciences 103 (16), pp.6100-6104 (2006)

A method to suppress the distortion of light spot during power amplification

We investigate the prominent role of 4f system in the suppression of beam shape distortion during laser power amplification. We find that 4f system can effectively suppress the distortion of the light spot caused by diffraction and thermal lens effect. In addition, the laser power can be amplified more efficiently by introducing a 4f system. Our results can benefit for applications with high requirements on the spot shape such as optical lattice and optical information processing.

Electro-optic diffractive multifocal lens with electrically reconfigurable multifocal planes

Despite the recent advances in correcting complex vision problems using the progressive addition lens, the narrow field of view of the lens often causes visual discomforts including dizziness and headache. The electro-optic lens technologies have shown promising potential for ophthalmic applications, but additional systems are needed to enable the time-multiplex switching of the focal power among multiple foci. Here, we demonstrate the electro-optic diffractive multifocal lens that provides multiple focal planes simultaneously by distributing the light pass through the lens to the zeroth and first-order diffraction focal planes of two LC diffractive lenses. The proposed LC diffractive lens offers six combinations of bifocal planes, nine combinations of trifocal planes, and 12 combinations of quadfocal planes that are electrically switchable without compromising the field of view when combined with a refractive lens such as a human crystalline lens. The diffractive multifocal lens technology shows promising potential for correcting ophthalmic vision problems as well as mitigating the vergence-accommodation conflict in augmented and virtual reality displays.

High-NA two-photon single cell imaging with remote focusing using a diffractive tunable lens.

Fast, volumetric structural and functional imaging of cellular and sub-cellular dynamics inside the living brain is one of the most desired capabilities in the neurosciences, but still faces serious challenges. Specifically, while few solutions for rapid 3D scanning exist, it is generally much easier to facilitate fast in-plane scanning than it is to scan axially at high speeds. Remote focusing in which the imaging plane is shifted along the optical axis by a tunable lens while maintaining the position of the sample and objective is a promising approach to increase the axial scan speed, but existing techniques often introduce severe optical aberrations in high-NA imaging systems, eliminating the possibility of diffraction-limited single-cell imaging. Here, we demonstrate near diffraction-limited, volumetric two-photon fluorescence microscopy in which we resolve the deep sub-micron structures of single microglia cells with axial scanning performed using a novel high-NA remote focusing method. Image contrast is maintained to within 7% compared to mechanical sample stepping and the focal volume remains nearly diffraction-limited over an axial range greater than 86 µm.

Adaptable Shack-Hartmann wavefront sensor with diffractive lenslet arrays to mitigate the effects of scintillation.

Adaptive optics systems are used to compensate for distortions of the wavefront of light induced by turbulence in the atmosphere. Shack-Hartmann wavefront sensors are used to measure this wavefront distortion before correction. However, in turbulence conditions where strong scintillation (intensity fluctuation) is present, these sensors show considerably worse performance. This is partly because the lenslet arrays of the sensor are designed without regard to scintillation and are not adaptable to changes in turbulence strength. Therefore, we have developed an adaptable Shack-Hartmann wavefront sensor that can flexibly exchange its lenslet array by relying on diffractive lenses displayed on a spatial light modulator instead of utilizing a physical microlens array. This paper presents the principle of the sensor, the design of a deterministic turbulence simulation test-bed, and an analysis how different lenslet arrays perform in scintillation conditions. Our experiments with different turbulence conditions showed that it is advantageous to increase the lenslet size when scintillation is present. The residual phase variance for an array with 24 lenslets was up to 71% lower than for a 112 lenslet array. This shows that the measurement error of focal spots has a strong influence on the performance of a Shack-Hartmann wavefront sensor and that in many cases it makes sense to increase the lenslet size. With our adaptable wavefront sensor such changes in lenslet configurations can be done very quickly and flexibly.

Focus‐Tunable Planar Lenses by Controlled Carriers over Exciton

AbstractWhile recent studies on nanoscale diffractive lenses demonstrate their potential as possible candidates for thin‐film display applications, their narrow focal ranges limit their application. Graphene, however, may realize focal controllability for its unique optoelectric property; due to its unique band structure among 2D materials, its carriers can be controlled by adjusting the Fermi level. Furthermore, due to the bandgap property of graphene, the intraband excitation of carriers is dominant over the interband excitation of carriers, which results in enhanced photonic transmission and reduced absorbance. Utilizing this property, graphene‐based ultrathin focusing device is fabricated that alters its optical characteristics when direct‐current voltage is applied producing vertical fringe‐specific electric field. The proposed device demonstrates 8.6% change in focal length and 48.85% focusing efficiency at wavelength of 405 nm. Overall, this study on electrically tunable ultrathin microlens introduces potential for holographic displays and expands the research scope in future display technologies.

Multifocal diffractive lens design in ophthalmology.

Multifocal diffractive lenses are used widely in ophthalmology. This paper provides a general mathematical formula to summarize various multifocal diffractive lens designs and introduces a novel, design: the subzonal multifocal diffractive (SMUD) lens. Analytical and numerical methods of SMUD lens design are elaborated in detail. A number of trifocal and quadrifocal SMUD lens designs of high diffraction efficiency are presented. Fresnel zone spacing factors are introduced to take into account the incidence of a converging or diverging beam and the curvature of the substrate on which the diffractive surface is created. Apodization and ophthalmic astigmatism correction related to diffractive lenses are also discussed.

Lens-based surgical correction of presbyopia. Where are we in 2020?

Presbyopia is the progressive and irreversible loss of accommodation due to aging. It is one of the main causes of loss of quality of life in people from 45 years of age, due to the, often novel, dependence on spectacles. The eagerness to correct it by ophthalmologists driven by the desire of millions of people who suffer from it, has become one of the main drivers for the development of intraocular lens (IOL) technology over the last twenty years. This review briefly presents the different alternatives that have allowed us to improve the crystalline lens surgical approach of presbyopia; from monofocal lenses and monovision technique, accommodation, refractive, and diffractive multifocal lenses, and finally the most recent focus or extended depth or focus/ field lenses known as EDOFs. Each IOL has its advantages, limitations and disadvantages. Furthermore, there is no single lens that suits the needs of all patients. It is necessary to know the variety of lenses available, and to have an in-depth understanding of their optical properties, as well as the impact that these will have later on their clinical performance and on the visual quality of the patients. This should help us to select the best alternative for each of them. La presbicia es la pérdida progresiva e irreversible de la acomodación debido al envejecimiento. Es una de las principales causas de disminución de la calidad de vida en personas a partir de los 45 años derivada de la, muchas veces novedosa, dependencia de las gafas. El afán por corregirla por parte de los oftalmólogos, impulsados por el deseo de millones de personas que la padecen, se ha convertido en uno de los principales motores de desarrollo de la tecnología de las lentes intraoculares (LIO) durante los últimos veinte años. Esta revisión repasa las distintas alternativas que han permitido ir mejorando el enfoque quirúrgico cristaliniano de la presbicia; desde las lentes monofocales y la técnica de la monovisión, a las lentes acomodativas, pasando por las lentes multifocales refractivas y difractivas y terminando con las más recientes lentes de foco o campo extendido conocidas como EDOF. Cada una de estas LIOs tiene sus ventajas, limitaciones e inconvenientes; y además, no existe la lente que se adapte a las necesidades de todos los pacientes. Es necesario conocer la variedad de lentes disponibles, y comprender en profundidad tanto sus propiedades ópticas como el impacto que éstas van a tener luego en su rendimiento clínico y en la calidad visual de los pacientes. Esto nos debería ayudar a poder seleccionar la mejor alternativa para cada uno de ellos.

Unilateral Versus Bilateral Refractive Lens Exchange With a Trifocal Intraocular Lens in Emmetropic Presbyopic Patients

PurposeTo compare visual outcomes and patient satisfaction between unilateral and bilateral trifocal diffractive intraocular lens (IOL) implantation in emmetropic patients with presbyopia. DesignRetrospective observational case series. MethodsThis is a multicenter, multisurgeon study of emmetropic presbyopes who underwent refractive lens exchange (RLE) followed by an implantation of FineVision IOL (PhysIOL). Inclusion criteria were emmetropic eyes, with a sphere between –0.25 and +0.50 diopters (D), cylinder of less than 0.75 D and spherical equivalent (SE) between –0.25 and +0.25 D. In addition, uncorrected distance visual acuity (UDVA) had to be Snellen >0.9 in each eye. A total of 171 eyes of 122 patients were evaluated. This sample was divided into 2 groups depending on whether they have been operated monocularly or binocularly. Visual and refractive performance, patient satisfaction, and spectacle independence were evaluated. ResultsUDVA and corrected distance visual acuity (CDVA) remained almost unchanged after monocular and binocular surgery. Binocular uncorrected intermediate (UIVA) and near visual acuity (UNVA) were better in those operated binocularly (0.3±0.12 vs 0.22±0.06, P < .063, and 0.09±0.08 vs 0.04±0.05, P < .027, respectively). Predictability and efficacy were higher in the binocular group, whereas safety was better in the monocular group. Visual dysphotopsia was worse and spectacle independence for all distances was higher in binocular group. ConclusionsOur research shows that RLE with binocular implantation of a trifocal diffractive IOL in presbyopic emmetropic patients is more successful in UNVA than monocular implantation. However, no significant differences were observed in UDVA, UIVA, and patient satisfaction.

Zones optimized multilevel diffractive lens for polarization-insensitive light focusing

In this study, we present the numerical design and experimental demonstration of an all-dielectric low refractive index polarization-insensitive multilevel diffractive lens (MDL) at microwave frequencies. The proposed MDL structure is composed of concentric rings (zones) having different widths and heights. Here, the heights and widths of each dielectric concentric rings of lens structure are optimized by using the differential evolution (DE) algorithm to obtain the desired polarization-insensitive focusing performance. The DE method is incorporated with the three-dimensional finite-difference time-domain method to design an MDL structure and evaluate its wave focusing ability. The design frequency is fixed to 10 GHz and, at the design frequency, the DE method is applied to achieve light focusing with the full-width at half-maximum (FWHM) values of 0.654λ and 0.731λ for transverse-magnetic (TM) and transverse-electric (TE) polarizations, respectively, where λ is the wavelength of incident light in free space. Moreover, focusing efficiencies and numerical apertures are calculated as 60.3% and 0.853 at the design frequency, respectively, for both polarizations. Besides, experimental verifications of the numerical results are carried out in microwave regime where the MDL design is fabricated by 3D printing technology by using a polylactic acid material. In the microwave experiments, MDL focuses the TM and TE polarized waves at the focal distances of 71.82 mm and 69.3 mm with the FWHM values of 0.701λ and 0.887λ, respectively. We believe that the proposed design approach can be further expanded to design low refractive index lenses for visible and near-infrared wavelengths.