Depth Of Focus Research Articles

Three-dimensional energy-controllable focal spot array with extended depth of focus created by pure phase modulation

Three-dimensional energy-controllable focal spot array with extended depth of focus created by pure phase modulation

Microfocused Ultrasound With Visualization Induces Remodeling of Collagen and Elastin Within the Skin.

Microfocused ultrasound with real-time visualization (MFU-V) is often used for noninvasive skin lifting, by precisely targeting dermal and subcutaneous tissues to create thermal coagulation points (TCPs). These TCPs denature collagen and initiate a transient inflammatory response, ultimately attracting dermal fibroblasts and inducing efficient neocollagenesis and extracellular matrix (ECM) remodeling, yielding to MFU-V's desired skin-lifting effects. The current study investigates MFU-V's underlying mode of action based on the histological progression of TCPs in the skin, providing new insight into the technology's regenerative effect. Following standard triple-depth MFU-V treatment, invivo skin samples were assessed using histology and immunohistochemistry to evaluate TCPs, heat shock protein (HSP47), and elastin expression in fibroblasts. MFU-V treatment induced elongated, flame-like TCPs with denatured collagen at focal depths of 1.5, 3.0, and 4.5 mm within the skin-each corresponding to its respective transducer depth. Time-dependent progression of TCPs showed significantly increased scores of fibroblasts and mature collagen along with recruitment of HSP47-positive fibroblasts to TCP areas on Day 90. Collagen formation and later maturation were visualized. Newly synthesized elastin significantly increased in the TCP area on Day 90 compared to Day 14. This work provides histological evidence of stimulation and regeneration of newly synthesized elastin fibers after TCP induction. MFU-V-generated TCPs triggered the body's own healing cascade of collagen denaturation, transient inflammation, proliferation, and tissue remodeling, resulting in attraction of HSP47-positive fibroblasts to the TCP sites, and new collagen and elastin fiber regeneration by fibroblasts. Besides the well-described neocollagenesis, this study demonstrates that MFU-V treatment induces elastin neogenesis that may result not only in skin lifting but also in improved skin elasticity, providing an overall regenerative effect.

Clinical outcomes with a new diffractive multifocal intraocular lens optimized by the dynamic light utilization algorithm.

To evaluate the refractive outcomes, optical performance, and the quality of vision in patients implanted with a new diffractive intraocular lens (IOL), the Intensity Hanita. This observational, prospective, longitudinal study included 64 eyes underwent bilateral cataract surgery with the Intensity IOL (Hanita Israel) implantation. Main outcome measures after 6 months were the following visual acuities (VAs) of uncorrected and corrected distance (UDVA and CDVA), uncorrected and distance corrected intermediate VAs (UIVA and DCIVA), uncorrected and distance corrected near (UNVA and DCNVA), refraction, slitlamp biomicroscopy, defocus curve (DFC),high ocular aberrations (HOA), contrast sensitivity (CS), optical quality, subjective quality of vision (QoV) and near activity visual questionnaires (NAVQ). Sixty-six percent of eyes having UDVA 0.10 logMAR or better. DFC showed maximum vision at distance (0.02 ± 0.07 LogMAR at 0.0 D), with flat decline through intermediate and near vision (0.11 ± 0.08 LogMAR at -1.5 D and 0.12 ± 0.12 at -2.5 D). No significant changes in CS were found (all spatial frequencies, p ≥ 0.06). The RMS of HOA, coma, trefoil, and SA were 0.21 ± 0.10, 0.10 ± 0.06, 0.11 ± 0.07, and 0.00 ± 0.04 μm and the Strehl ratio was 0.12 ± .04 at 6 months. Subjective symptoms (halos and glare) were reported mild but well tolerated, not causing significant disturbance in daily activities. The NAVQ showed high levels of satisfaction performing daily near-vision tasks. The Hanita Intensity diffractive IOL successfully restores all distances of vision. The flat profile of the monocular defocus curve confirms the five-foci distribution principle that provides vision at all ranges while increasing the depth of focus.

Effects of long-term neural adaptation to habitual sspherical aberration on through-focus visual acuity in adults

We investigated how long-term visual experience with habitual spherical aberration (SA) influences subjective depth of focus (DoF). Nine healthy cycloplegic eyes with habitual SAs of different signs and magnitudes were enrolled. An adaptive optics (AO) visual simulator was used to measure through-focus high-contrast visual acuity after correcting all monochromatic aberrations and imposing + 0.5 μm and − 0.5 μm SAs for a 6-mm pupil. The positive (n = 6) and negative (n = 3) habitual SA groups ranged from 0.17 to 0.8 μm and from − 1.2 to – 0.12 μm for a 6-mm pupil, respectively. Although all optical conditions were identical, and the subjective DoFs were expected to be the same for all participants, the DoFs of individuals differed between the positive and negative habitual SA groups. For the positive habitual SA group, the mean DoF with positive AO-induced SA (2.14 D) was larger than that with negative AO-induced SA (1.88 D); for the negative habitual SA group, a smaller DoF was measured with positive AO-induced SA (1.94 D) than that with negative AO-induced SA (2.14 D). Subjective DoF tended to be larger when the induced SA in terms of sign and magnitude was closer to the participant’s habitual SA. Our findings suggest that neural adaptation to habitual SA compensated for optical blur at multiple object distances, perceptually expanding DoF. As a result, the outcomes of optical treatments for presbyopia may differ due to the neural compensation mechanism influenced by an individual’s visual experience with their habitual optics.

Realization of Airy pattern acoustic bullets by depth of focus synthesis.

Energy concentration is a key parameter for the characterization of light or acoustic bullets. To the best of our knowledge, the highest encircled-energy ratio in the mainlobe reported is merely 25% for the solitary bullet waves and 30% for the nonsolitary bullet waves. This letter reports experimentally and theoretically on a new family of acoustic bullets, namely, Airy pattern ultrasonic bullets, realized by the depth of focus synthesis. The Airy pattern ultrasonic bullets, regarded as a beam with an ultra-long depth of focus, exhibit Airy pattern energy distribution and contain 83.8% of total energy in their mainlobe. In the depth of focus synthesis proposed, an ultra-long depth of focus could be longitudinally synthesized by successive acoustic foci by using an acoustic reflection cavity (ARC). In contrast to the well-known aperture synthesis which utilizes a platform motion to extend the aperture, the depth of focus synthesis employs multiple reflections in ARC to extend its physical dimensions. The Airy pattern ultrasonic bullets presented would be potentially useful in long-range ultrasound imaging, ultrasonic therapy, and acoustic wireless energy transmission.

Reading Performance Following Contralateral Implantation of an Extended Depth of Focus (EDOF) IOL and a Hybrid EDOF Multifocal IOL.

To assess objective reading performance at intermediate and near distances using the Salzberg Reading Desk (SRD) (SRD Vision) in patients with cataract who underwent the implantation of a diffractive extended depth of focus intraocular lens (EDOF IOL) in the dominant eye and a hybrid multifocal EDOF IOL in the non-dominant eye. This prospective, non-comparative, interventional study included 46 eyes of 23 patients with cataract who underwent bilateral cataract surgery with implantation of the DFR00V Tecnis Synergy IOL (Johnson & Johnson Surgical Vision) in the non-dominant eye and the DXR00V Tecnis Symfony OptiBlue IOL (Johnson & Johnson Surgical Vision) in the dominant eye. At postoperative 6 months, the Salzburg Reading Desk was used to assess distance-corrected reading performance at near and intermediate distances. Although the monocular reading acuity at the preferred intermediate distance was statistically significantly better in the eyes implanted with the DXR00V IOL, it was better with the DFR00V IOL at preferred near distances. The mean binocular distance-corrected preferred intermediate and near reading acuity was 0.07 ± 0.09 (20/23) and 0.13 ± 0.09 (20/27) logarithm of the minimum angle of resolution, respectively. Other parameters of reading performance, such as reading speed, reading distance, reading time, and smallest scale log print size, were similar between the two IOL groups when assessed monocularly. Implanting a DFR00V IOL in the non-dominant eye and a diffractive DXR00V IOL in the dominant eye resulted in excellent binocular reading acuity and speed at intermediate and near distances. [J Refract Surg. 2024;40(11):e778-e782.].

Visual Outcomes After Cataract Surgery With the Light Adjustable Lens in Japanese Patients With and Without Prior Corneal Refractive Surgery.

To describe Light Adjustable Lens (RxSight, Inc) (LAL) visual and refractive outcomes in a Japanese patient population with and without prior refractive surgery. In this retrospective chart review of patients with cataract in a private eye clinic, 34 eyes from 21 patients underwent cataract surgery with LAL implantation. Eyes underwent light treatment to adjust the patients' refraction after implantation to meet individual visual goals. Standard visual and refractive outcomes were collected. Contrast sensitivity (to assess quality of vision), clinical defocus and vergence curves (to assess range of vision), and patient satisfaction were also collected. The mean prediction error of the light adjustment was -0.04 ± -0.48. Thirty-one eyes (91%) and 33 eyes (97%) were within ±0.25 and ±0.50 diopters (D) of manifest spherical equivalent target, respectively. Thirty-two eyes (94%) had residual refractive cylinder of 0.50 D or less. The full depth of focus was 3.68 D. Monocular contrast sensitivity shows frequencies equivalent to a normal population aged 50 to 60 years. The mean satisfaction score was 8.8 (scale: 1 to 10). There were no adverse events and no eyes lost corrected distance visual acuity from the light treatment. LALs in cataract refractive surgery hold great promise, including for the Japanese population, which have unique ocular biometrics. By providing a safe procedure and the ability for postoperative adjustments, the LAL provided a tailored approach to vision correction, ultimately improving patient outcomes and satisfaction. [J Refract Surg. 2024;40(11):e854-e862.].

Influence of astigmatic aberration on partially coherent Gaussian-Schell vortex beam focused by lensacon

Based on the mathematical framework of the partially coherent Gaussian Schell model vortex (PCGSMV) beam and the Huygens-Fresnel integral, we conducted a study to analyze the intensity distribution and depth of focus (DOF) of the PCGSMV beam as it propagates through a classical axicon. Our numerical results indicate the influence of factors such as the beam width, spatial degree of coherence, topological charge, and axicon base angle on the intensity distribution and DOF. In addition, we investigated the relationship between the beam spot size and propagation distance, as well as the effects of the spatial degree of coherence and propagation distance on the intensity profile. Our findings highlight the importance of the intensity values along the DOF for various applications, including the optical trapping and manipulation of micro particles.

Low-cost, high-volume, manufacturable 0.88 NA multi-wavelength diffractive lens array for optical document security

We design, manufacture, and characterize a high-numerical-aperture (NA=0.88, f/0.27), multi-wavelength (480 nm, 550 nm, and 650 nm) multilevel diffractive microlens array (MLA). This MLA achieves multi-wavelength focusing with a depth of focus (DoF) twice the diffraction-limited value. Each microlens in the array is closely packed with a diameter of 70 µm and a focal length of 19 µm in air. The MLA is patterned on one surface of a polymer film via UV casting, positioning the focal plane at the distal end of the polymer film. Each microlens focuses light at three design wavelengths into a focal spot with an estimated FWHM of ∼310nm. By placing this MLA directly on a standard high-resolution banknote print (minimum feature width of 10–15 µm), we demonstrate color-integral imaging for anti-counterfeiting. In contrast, refractive MLAs cannot achieve high-NA, multi-wavelength focusing or extended DoF. The extended DoF of our MLA ensures reliable performance despite variations in the polymer film’s thickness. Our MLA, produced via UV casting, enables extremely low-cost, high-volume production, making it ideal for flat optics in banknotes and document security.

Onsite Seismic Monitoring Behavior of Undamaged Dams During the 2023 Kahramanmaraş Earthquakes (M7.7 and M7.6).

On 6 February 2023, two major earthquakes struck Türkiye, with their epicenters in the Pazarcık (M7.7; focal depth: 8.6 km) and Elbistan (M7.6; focal depth: 7 km) districts of Kahramanmaraş city. Most of the dams in the earthquake region remained structurally safe and stable. However, 17 dams in Türkiye and 1 dam in Syria were damaged during the 2023 Kahramanmaraş earthquakes. The main objective of this study was to better understand the real seismic behaviors of the dams during the two mainshocks and significant aftershocks. An earthfill dam, a concrete-faced rockfill dam (CFRD), and a roller-compacted concrete (RCC) dam constructed in the disaster area were selected to identify the real seismic behaviors of different types of dams during strong earthquakes. Acceleration records measured at the crest, right and left abutments, and foundations of the selected dams during the 2023 Kahramanmaraş earthquakes were taken into account to determine the real seismic behavior of the dams before, during, and after the earthquakes. The results of this investigation provide valuable insights into the real seismic behaviors of different types of dams in the vicinity of fault lines during strong earthquakes.

Target-specified reference-based deep learning network for joint image deblurring and resolution enhancement in surgical zoom lens camera calibration

Background and objectiveFor the augmented reality of surgical navigation, which overlays a 3D model of the surgical target on an image, accurate camera calibration is imperative. However, when the checkerboard images for calibration are captured using a surgical microscope having high magnification, blur owing to the narrow depth of focus and blocking artifacts caused by limited resolution around the fine edges occur. These artifacts strongly affect the localization of corner points of the checkerboard in these images, resulting in inaccurate calibration, which leads to a large displacement in augmented reality. To solve this problem, in this study, we proposed a novel target-specific deep learning network that simultaneously enhances both the blur and spatial resolution of an image for surgical zoom lens camera calibration. MethodsAs a scheme of an end-to-end convolutional deep neural network, the proposed network is specifically intended for the checkerboard image enhancement used in camera calibration. Through the symmetric architecture of the network, which consists of encoding and decoding layers, the distinctive spatial features of the encoding layers are transferred and merged with the output of the decoding layers. Additionally, by integrating a multi-frame framework including subpixel motion estimation and ideal reference image with the symmetric architecture, joint image deblurring and enhanced resolution were efficiently achieved. ResultsFrom experimental comparisons, we verified the capability of the proposed method to improve the subjective and objective performances of surgical microscope calibration. Furthermore, we confirmed that the augmented reality overlap ratio, which quantitatively indicates augmented reality accuracy, from calibration with the enhanced image of the proposed method is higher than that of the previous methods. ConclusionsThese findings suggest that the proposed network provides sharp high-resolution images from blurry low-resolution inputs. Furthermore, we demonstrate superior performance in camera calibration by using surgical microscopic images, thus showing its potential applications in the field of practical surgical navigation.

Impact of pupil size and corneal spherical aberrations on the performance of monofocal intraocular lenses: an experimental model

In this study, an in vitro comparison of the optical performances of three models (spherical, aberration-neutral, and aberration-correcting) of monofocal intraocular lenses (IOLs) is proposed. A comprehensive model is employed, encompassing a wide range of corneal models and aperture sizes, reflecting the high variability of corneal spherical aberrations (SA) and pupil sizes in both normal and postoperative refractive corneal surgery populations. Analysis of average through-focus modulation transfer function (MTF) curves reveals significant differences in optical performance attributable to pupil size and corneal SA. These differences depend on the IOL model and affects MTFmax (representing contrast at best focus), depth of focus, refractive error tolerance, and the effective power of the lens.

Generation of scalar and vector beams with longitudinally varying polarization based on all-silicon metasurfaces

Beams with longitudinally continuously varying polarization provide a new application dimension in fields such as optical communication and optical manipulation. The small-sized and multifunctional metasurfaces have been used to generate scalar or vector beams whose polarizations vary along the propagation direction within a single polarization mode. However, dual-mode beams with longitudinally varying polarization can further increase the dimension of manipulation, but they have been rarely explored. Here, we propose a scheme based on the spatial partitioning method for designing dual-mode beams with longitudinally evolving polarization. To validate the proposed scheme, we demonstrate three dual-mode beams generated by all-silicon metasurfaces which have evolving polarization from scalar to vector, scalar vortex to vector vortex, and first-order to second-order cylindrical vector, respectively. The transverse polarization distributions of these beams depend on their longitudinal position. The different focal lengths of the orthogonal circularly polarized components and the design of long focal depth make it possible to change the polarization distribution longitudinally. The optical fields generated based on the proposed scheme are expected to be applied in depth detection and optical manipulation.

Precision Seismicity of the San Andreas Fault System in Central California: Insights into Active Tectonics and Earthquake Physics

Since the late 1960s, seismicity of the San Andreas Fault system in central California has been under intense observation by U. S. Geological Survey’s Northern California Seismic Network (NCSN). Designed to provide accurate focal depth control and a low magnitude of catalog completeness, the network maps fault, both large and small across the full breadth of this 400-kilometer-long portion of the plate boundary, including many that are known only from their seismicity. Beginning in 1984, with the advent of routine digital recording, new opportunities were created to significantly enhance the spatial resolution of seismicity. This led to the co-evolution of method that take full advantage of digital waveforms and new insights into the nature of seismicity and faults. Collectively referred to as precision seismicity, discoveries included repeating earthquakes and highly organized and stable distributions of seismicity on major faults. Long term observation of seismicity before and after the six largest earthquakes over the last half-century underscore the outstanding challenges for earthquake predictability and theories of earthquake nucleation.

Image-Based Auto-Focus Microscope System with Visual Servo Control for Micro-Stereolithography.

Micro-stereolithography (μSL) is an advanced additive manufacturing technique that enables the fabrication of highly precise microstructures with fine feature resolution. One of the primary challenges in μSL is achieving and maintaining precise focus throughout the fabrication process. For the successful application of μSL, it is essential to maintain the sample surface within a focal depth of several microns. Despite the growing interest in auto-focus devices, limited attention has been directed towards auto-focus systems in image-based auto-focus microscope systems for precision μSL. To address this challenge, we propose an image-based auto-focus microscope system incorporating visual servo control. In the optical design, a transflective beam splitter is employed, allowing the laser beam to pass through for fabrication while reflecting the focused beam on the sample surface to the microscope and camera. Utilizing captured spot images and the Foucault knife-edge test, a deep learning-based laser spot image processing algorithm is developed to determine the focus position based on spot size and the number of spot pixels on both sides. Experimental results demonstrate that the proposed auto-focus system effectively determines the relative position of the focal point using the laser spot image and achieves auto-focusing through visual servo control.

Generating sub-diffraction microwave needle beam for nondestructive testing by multifunctional transmissive metasurfaces

Sub-diffraction needle beams with high intensity, sub-diffraction focal size, and long depth of focus (DOF) have attracted many researchers’ attention. However, the traditional methods for needle beam generation typically require many devices, such as phase elements, amplitude filters, and lens, which leads to a complex and bulky system and unfavorable for their integration. To address these challenges, we use a single multifunctional transmissive metasurface to convert a linearly polarized plane wave into a needle beam in the microwave range. The guided wave inspired unit cells of the proposed metasurface is designed to simultaneously and independently modulate the polarization and phase of transmitted waves. By imposing the desired polarization and phase distributions on the metasurface, the proposed multifunctional transmissive metasurface can efficiently generate a needle beam with subdiffraction size and extended DOF at 10 GHz when it is illuminated by an x-polarized wave. The proposed metasurface is fabricated, and a sub-diffraction needle beam with good performance is obtained in our measurements. In addition, a proof-of-concept of a high-resolution nondestructive testing experiment based on our designed metasurface is accomplished. Our work is expected to have potential applications in nondestructive testing of materials and structures.

Large-scale fabrication of meta-axicon with circular polarization on CMOS platform

Abstract Metasurfaces, consisting of arrays of subwavelength structures, are lightweight and compact while being capable of implementing the functions of traditional bulky optical components. Furthermore, they have the potential to significantly improve complex optical systems in terms of space and cost, as they can simultaneously implement multiple functions. The wafer-scale mass production method based on the CMOS (complementary metal oxide semiconductor) process plays a crucial role in the modern semiconductor industry. This approach can also be applied to the production of metasurfaces, thereby accelerating the entry of metasurfaces into industrial applications. In this study, we demonstrated the mass production of large-area meta-axicons with a diameter of 2 mm on an 8-inch wafer using DUV (Deep Ultraviolet) photolithography. The proposed meta-axicon designed here is based on PB (Pancharatnam–Berry) phase and is engineered to simultaneously modulate the phase and polarization of light. In practice, the fabricated meta-axicon generated a circularly polarized Bessel beam with a depth of focus (DoF) of approximately 2.3 mm in the vicinity of 980 nm. We anticipate that the mass production of large-area meta-axicons on this CMOS platform can offer various advantages in optical communication, laser drilling, optical trapping, and tweezing applications.

A Damping Modification Factor Prediction Model for Horizontal Pseudoacceleration Spectrum for Subduction Slab Earthquakes Using Offshore Ground Motions in the Japan Trench Area

ABSTRACT This study develops a damping modification factor (DMF) model for offshore ground motion from subduction slab earthquakes that is a function of the damping ratio, spectral period, moment magnitude, focal depth, and rupture distance. The DMF values for 10 damping ratios between 1% and 30% and 34 spectral periods ranging from 0.03 to 5.0 s are calculated using 2803 offshore ground-motion records obtained from the S-net in Japan. An examination of the residuals from a median model, which considers deployment methods, indicates that DMF is influenced by parameters such as magnitude, depth, and distance. The DMF model includes the following components: a median model considering deployment method, a magnitude linear term, a magnitude square term, a focal depth term, an ln(R) scaling, and a constant term. The influence of damping ratio on model coefficients can be simulated by a quadratic function of the damping ratio. In addition, we established a DMF standard deviation model, for which the influence of damping ratio and spectral period on the standard deviation can be simulated by a quadratic function of the damping ratio and a quartic polynomial of the spectral period, respectively. The uncertainty related to the path and site effects is the main source of the deviation of the DMF model. We have conducted a comparison between the offshore DMF model and onshore model proposed by Rezaeian, Al Atik, et al. (2021), revealing that for lower damping ratios, the offshore DMF is generally lower at periods less than 0.2 s and larger at periods greater than 2.0 s compared to its onshore counterparts. The offshore DMF model adjusts the acceleration spectrum proposed by Tan and Hu (2024) to generate smooth pseudoacceleration spectra for most spectral periods.

Ultrathin metasurface for super multi-view 3D display with linear and circular polarization control

Multiview 3D display technologies are advantageous due to their smooth motion parallax, visual discomfort alleviation, and wide depth of focus. However, the potential applications of this technology are constrained by its bulky size and limited light modulation capability. Metasurfaces offer diverse wavefront control by manipulating the phase, amplitude, and polarization of light. They provide design freedom and high image quality for multiview 3D display technologies. Here, we propose an ultrathin metasurface-based super multiview 3D display that can effectively modulate the flexibility of linearly polarized (LP) and circularly polarized (CP) electromagnetic waves. Numerical results demonstrate that it can produce 24 views together for LP and CP waves and high-quality reconstructed 3D images are obtained. The suggested metasurface for super multiview 3D display is promising to underpin the advancement of meta-optics-based operations in 3D display, imaging and integrated optics.

Comparative analysis of modulation transfer function in various intraocular lenses under normal, decentration, and tilt conditions

PurposeThis study aims to compare the modulation transfer function (MTF) of different intraocular lenses (IOLs) under normal, decentration, and tilt conditions to evaluate their optical performance. DesignExperimental setting. MethodsA total of 12 IOL models (+20 D diopter, n = 3 each) were measured for MTF using the OptiSpheric IOL system with a 3 mm aperture diameter at a water temperature of 35 °C. Measurements were made with a spatial frequency of 0 - 200 lp/mm at the normal, decentration of 0.5 mm, and tilt of 5° positions. ResultsThe MTF values were significantly different between normal and decentration conditions for XY1A (monofocal, toric) (P = 0.03), Tecnis ZCB00V (P = 0.0009), and NS-60YG (P = 0.004). Differences were significant between normal and tilt conditions for MP70 (P = 0.009), XY1 (P = 0.0005), and Clareon (P = 0.049), and were significant between decentration and tilt conditions only for LentisComfort (bifocal) (P = 0.01). With normal condition, MTF of Eyhance DIB00V (extended depth of focus) showed significant differences with 11 other IOLs (P < 0.0001), while LentisComfort exhibited differences with 10 other IOLs (P < 0.0001) except for XY1A (P = 0.0002). Similarly, with decentration condition, Eyhance DIB00V differed significantly from 11 other IOLs (P < 0.0001). With tilt condition, Eyhance DIB00V showed significant differences with 10 other IOLs (P < 0.0001) except for LentisComfort, which itself differed significantly from 10 other IOLs (P < 0.0001). ConclusionsIn the experimental settings, while specialized IOLs can address specific visual issues, monofocal IOLs remain superior in terms of overall contrast transfer quality and resolution even in the implanted IOL position is not ideal. These results provide a basis for recommending the use of monofocal IOLs in cases where the anterior chamber depth and lens position are prone to instability, such as in eyes with weakened zonules or following glaucoma filtering surgery.