Entrance Pupil Research Articles

Retinal image quality with myopia control lenses, in the synthetic accommodative wavefront model

Aims/Purpose: Current myopia control contact lenses (CLs) are based on multifocality designs that affect decrease retinal image quality (RIQ). This study aimed to evaluate the changes in RIQ and accommodative response (AR) with two myopia control CLs.Methods: 100 synthetic eyes were generated using anc accommodative wavefront model to simulate the changes in RIQ with accommodation. The synthetic eyes were “fitted”, using direct wavefront summation, with two myopia control CLs: the MiSight with +2.00D treatment zones and the Mylo with an EDOF design. Peak image quality was calculated for the naked eye and with CLs, in the relaxed state and a target vergence of 40 cm, with an entrance pupil diameter of 4.28 mm. Additionally, the AR that maximizes RIQ was calculated.Results: The mean RIQ [ranged from 0 to 1] for the relaxed eye was 0.42 ± 0.10 without a CLs. It halved to 0.26 ± 0.05 with the Misight and reduced by threefold to 0.15 ± 0.04 with the Mylo. For 40cm the RIQ was 0.34 ± 0.09 without a CL, 0.24 ± 0.07 with the Misight and 0.19 ± 0.03 with the Mylo.For target vergences with demands close the effective add power of the CL, the accommodative RIQ through‐focus produced a second peak prior to the maximum peak, correspondent to the focusing power of the treatment zones1, yielding a RIQ of 0.08 ± 0.03 and 0.12 ± 0.04 for the Misight and Mylo, respectively. The AR without CL was 2.33 ± 0.20 D, 1.75 ± 0.22 D and 1.75 ± 0.22 D with the Misight and the Mylo, respectively.Conclusions: Both myopia control CLs reduced the RIQ in the relaxed and accommodated states. For 40 cm, both CLs induce a secondary peak in the RIQ through‐focus. With Mylo, the secondary peak appeared less than 0.1D from the maximum peak, possibly due to its EDOF design. The AR was reduced with both CLs 0.58 D (lag) compared to the naked eye condition. These results indicate that, both lenses impose significant limitations RIQ and AR.

Retinal image quality with myopia control lenses, in the synthetic accommodative wavefront model

Aims/Purpose: Current myopia control contact lenses (CLs) are based on multifocality designs that affect decrease retinal image quality (RIQ). This study aimed to evaluate the changes in RIQ and accommodative response (AR) with two myopia control CLs.Methods: 100 synthetic eyes were generated using anc accommodative wavefront model to simulate the changes in RIQ with accommodation. The synthetic eyes were “fitted”, using direct wavefront summation, with two myopia control CLs: the MiSight with +2.00D treatment zones and the Mylo with an EDOF design. Peak image quality was calculated for the naked eye and with CLs, in the relaxed state and a target vergence of 40 cm, with an entrance pupil diameter of 4.28 mm. Additionally, the AR that maximizes RIQ was calculated.Results: The mean RIQ [ranged from 0 to 1] for the relaxed eye was 0.42 ± 0.10 without a CLs. It halved to 0.26 ± 0.05 with the Misight and reduced by threefold to 0.15 ± 0.04 with the Mylo. For 40cm the RIQ was 0.34 ± 0.09 without a CL, 0.24 ± 0.07 with the Misight and 0.19 ± 0.03 with the Mylo.For target vergences with demands close the effective add power of the CL, the accommodative RIQ through‐focus produced a second peak prior to the maximum peak, correspondent to the focusing power of the treatment zones1, yielding a RIQ of 0.08 ± 0.03 and 0.12 ± 0.04 for the Misight and Mylo, respectively. The AR without CL was 2.33 ± 0.20 D, 1.75 ± 0.22 D and 1.75 ± 0.22 D with the Misight and the Mylo, respectively.Conclusions: Both myopia control CLs reduced the RIQ in the relaxed and accommodated states. For 40 cm, both CLs induce a secondary peak in the RIQ through‐focus. With Mylo, the secondary peak appeared less than 0.1D from the maximum peak, possibly due to its EDOF design. The AR was reduced with both CLs 0.58 D (lag) compared to the naked eye condition. These results indicate that, both lenses impose significant limitations RIQ and AR.References Faria‐Ribeiro M, Amorim‐de‐Sousa A, González‐Méijome JM. Predicted accommodative response from image quality in young eyes fitted with different dual‐focus designs. Ophthalmic Physiol Opt. 2018;38(3):309‐16.

Research on the Earth Reflected Solar Spectral Radiation Observation System Based on the Lagrange L1 Point of the Earth–Moon System

We propose an observation system based on the Lagrange L1 point of the Earth–Moon system to observe solar spectral radiation reflected from the Earth, enabling continuous hyperspectral observation of the Earth’s hemisphere. The system can observe the solar spectral radiation reflected by the Moon, with its data applicable to on-orbit spectral radiation calibration. In this paper, the spectral irradiance at the entrance pupil of the Earth spectral radiation observation system (ESROS) is analyzed, and the optical design of the ESROS is introduced. An off-axis two-mirror telescope system, a coupling system of a microlens array and a fiber bundle, and an optical splitting system based on concave grating are used to achieve the full field of view hyperspectral splitting and miniaturization of the instrument. Finally, the stray radiation suppression of the instrument is introduced. The results show that the spectral resolution of the system is better than 5 nm in the 380–1000 nm band, and the spectral resolution is better than 10 nm in the 1000–1700 nm band. When observing the Earth, the signal-to-noise ratio is greater than 200. The external stray radiation suppression reaches the order of 10−9. The ESROS will provide crucial data support for researching global energy balance, climate change, and the spectral characteristics of exoplanets, facilitating planetary science and the exploration of extraterrestrial life.

Inverse Design of Aberration-Corrected Hybrid Metalenses for Large Field of View Thermal Imaging Across the Entire Longwave Infrared Atmospheric Window.

Long wave infrared (LWIR) cameras play a pivotal role across diverse applications due to their distinctive features. The growing demand for high-performance thermal imaging optics, characterized by a broad working bandwidth, large field of view (FOV), aberration-free design, lightweight construction, compactness, and cost-effectiveness, poses significant challenges for LWIR lens design. Here, we propose an inverse design method for LWIR hybrid metalenses, specifically aiming to achieve aberration-corrected thermal imaging with both a large FOV and a broad working bandwidth. Our approach involves optimizing phase profiles of metalens' unit cells guided by a loss function that compares the hybrid lens design to diffraction-limited results for various incident angles and wavelengths. As a result, we demonstrate an aberration-corrected thermal camera with a 30° FOV and an achromatic working bandwidth spanning the entire LWIR atmospheric window (8 to 14 μm). Significantly, the total optical path length, the entrance pupil to the sensor plane of the charge-coupled device (CCD), is a mere 13.6 mm. Our work merits advantages in the FOV, working bandwidth, and compactness, which surpass state-of-the-art LWIR hybrid metalens designs and find numerous imaging and sensing applications.

Optical System Design of a Self-Calibrating Real Entrance Pupil Imaging Spectrometer

Presently, on-orbit calibration methods have several problems, such as low calibration accuracy and broken traceability links, so an urgent need exists to unify traceable and high-precision on-orbit radiometric calibration loads as benchmarks for cross-transfer radiometric calibration. Considering the deficiencies of current on-orbit calibration, this paper proposes adjusting the size of the variable diaphragm at the entrance pupil and the integration time to attain large dynamic attenuation, converting the radiometric calibration into absolute geometric calibration of the attenuation device, and realizing a self-calibrating real entrance pupil imaging spectrometer (SCREPIS) that can be directly used to view the Earth and the Sun and quickly obtain apparent reflectance data. An initial structural design method based on the distance between individual mirrors is proposed according to the instrument design requirements. The design of a real entry pupil image-side telecentricity off-axis three-reflector front optical system with a 7° field of view along the slit direction, a 3.7 systematic F-number, and a 93 mm focal length is finally realized, and the system image plane energy is verified to change proportionally to the variable diaphragm area. Finally, the front system and rear Offner optical system are jointly simulated and optically designed. The system provides instrumental support for cross-calibration and theoretical support and a technical basis for planning space-based radiation references.

High-Performance Telescope System Design for Space-Based Gravitational Waves Detection.

Space-based gravitational wave (GW) detection employs the Michelson interferometry principle to construct ultra-long baseline laser interferometers in space for detecting GW signals with a frequency band of 10-4-1 Hz. The spaceborne telescope, as a core component directly integrated into the laser link, comes in various configurations, with the off-axis four-mirror design being the most prevalent. In this paper, we present a high-performance design based on this configuration, which exhibits a stable structure, ultra-low wavefront aberration, and high-level stray light suppression capabilities, effectively eliminating background noise. Also, a scientifically justified positioning of the entrance and exit pupils has been implemented, thereby paving adequate spatial provision for the integration of subsequent optical systems. The final design realizes a wavefront error of less than λ/500 in the science field of view, and after tolerance allocation and Monte Carlo analysis, a wavefront error of less than λ/30 can be achieved with a probability of 92%. The chief ray spot diagram dimensions are significantly small, indicating excellent control of pupil aberrations. Additionally, the tilt-to-length (TTL) noise and stray light meet the stringent requirements for space-based gravitational wave detection. The refined design presented in this paper proves to be a more fitting candidate for GW detection projects, offering more accurate and rational guidance.

Iterative critical ray tracing for local tolerance analysis of freeform imaging systems

Tolerance analysis of the freeform surfaces serves as a critical bridge between design and manufacturing, offering essential guidance for the desensitization design of optical systems and playing a crucial role in the development of advanced imaging systems. Recently, Deng et al. proposed a direct method [Deng et al. Optica 9, 1039 (2022)] for solving tolerances of freeform surfaces, which reveals the local characteristics of the tolerances of freeform surfaces. However, the method requires dense sampling of the fields of view (FOVs) and the entrance pupil (EP) to cover as many optical surface points as possible, thereby achieving more accurate tolerance envelope solutions. Here, we propose an iterative algorithm called "critical ray tracing" to calculate the critical rays at points on the optical surface and utilize this information for surface tolerance analysis. This method involves fitting the coordinate space of the optical system into a 4D polynomial and employing numerical iteration to determine the rays closest to the preset wave aberration boundary at each surface point. Converting the FOVs and EP sampling into optical surface sampling significantly reduces the number of samples required, achieving computational efficiency without compromising accuracy in determining tolerable surface errors. We demonstrate the effectiveness of our method through tolerance analysis of two different freeform imaging systems. Furthermore, a tolerance analysis example of a complete off-axis three-mirror optical system demonstrates the universality of the process.

Study of the Dispersion Compensation Double-Layer Diffractive Optical Components Based on Metasurface and Grating, and Their Application in Augmented Reality Displays.

We employed a double-layer coupled diffractive optical element, based on metasurfaces and diffraction gratings, which exhibits wavefront modulation and chromatic dispersion compensation. Utilizing this double-layer coupled diffractive optical element in the optical information transmission process of a diffractive waveguide allows for the transmission of color image information using a single-layer waveguide structure. Our results demonstrate that, under the conditions of a field of view of 47° × 47°, an entrance pupil size of 2.9 × 2.9 mm2, and an exit pupil extension size of 8.9 mm, the uniformity of the brightness for each monochromatic field reached 85%, while the uniformity of color transmission efficiency exceeded 95%.

Design of waveguide with double layer diffractive optical elements for augmented reality displays

We investigated a diffraction optical waveguide structure with a double layer coupling configuration. This double layer-coupled diffraction optical waveguide structure modulates light information through wavefront modulation for propagation within the optical waveguide and then reproduces the light information through further wavefront modulation, thus achieving optical information transmission. Analysis indicates that the theoretical maximum field of view can reach 90° × 90°. With an actual field of view set to 53° × 53°, an entrance pupil size of 3.2 × 3.2 mm², an eye relief of 10 mm, and 50 pupil expansion, the system’s total energy transmission efficiency is 37%, with field of view uniformity at 91% and uniformity within the eye movement range reaching 97%.

Design and Manufacture of 30-Degree Projection Lens for Augmented Reality Waveguide.

A projection lens with a 30-degree field of view is developed for use in augmented reality (AR) glasses, including a waveguide combiner designed for a 0.35-inch LCoS panel. The entrance pupil diameter of the lens is 14 mm and the lens has an effective focal length of 16.443 mm; an F-number of 1.175. This paper has four key issues: optical projection lens design, lens manufacturing and assembly tolerance analysis, projection lens resolution testing, and AR glasses system resolution testing of panel images projected by the projection lens. After lens manufacture, the lens was tested, achieving a central field image quality of 57 cycles/mm, an angular resolution of 33 pixels per degree (PPD), a 0.7 field image quality of 40.3 cycles/mm, and an angular resolution of 23 pixels per degree (PPD). Imaging performance testing based on a diffraction-type waveguide shows a resolution of 57 cycles/mm in the center area and an angular resolution of 33 PPD.

Differential image motion in astrometric observations with very large seeing-limited telescopes

We investigate how to quantitatively model the observed differential image motion (DIM) in relative astrometric observations. As a test bed we used differential astrometric observations from the FORS2 camera of the Very Large Telescope (VLT) obtained during 2010--2019 under several programs of observations of southern brown dwarfs . The measured image motion was compared to models that decompose atmospheric turbulence in frequency space and translate the vertical turbulence profile into DIM amplitude. This approach accounts for the spatial filtering by the telescope's entrance pupil and the observation parameters (field size, zenith angle, reference star brightness and distribution, and exposure time), and it aggregates that information into a newly defined metric integral term. We demonstrate excellent agreement (within 1<!PCT!>) between the model parameters derived from the DIM variance and determined by the observations. For a 30 s exposure of a typical 1 field close to the Galactic plane, image motion limits astrometric precision to sim 60 mu as when sixth-order transformation polynomial is applicable. We confirm that the measured image motion variance is well described by Kolmogorov-type turbulence with exponent 11/3 dependence on the field size at effective altitudes of 16--18 km, where the best part of the DIM is generated. Extrapolation to observations with extremely large telescopes enables the estimation of the astrometric precision limit for seeing-limited observations of sim 5 mu as, which has a variety of exciting scientific applications.

Wall Shear Stress Characteristics Of A Turbulent Boundary Layer Obtained With Multi-Aperture Defocusing Micro-PTV And High-Speed Stereo Profile-PIV

A multi-aperture 3d 3c micro PTV system is presented which relies on single window optical access for both high-speed tracer illumination and image recording. Similar to the “defocusing” concept described by C. Willert & Gharib (1992), the wall distance of individual particles is obtained from the size of projected particle image triplets formed by a triplet of apertures on the entrance pupil of the microscope lens. The present article extends upon previously published material Klinner & Willert (2022) by applying multi-aperture micro particle tracking velocimetry (MA-micro PTV) on a canonical turbulent boundary layer (TBL) to track the near-wall motion of tracer particles with the aim of estimating the unsteady wall-shear stress from particle tracks. The technique is validated with measurements of a TBL inside the closed test section of the 1 m wind tunnel of DLR in Göttingen (1mWK) at free- stream velocities of 5.2 to 20 m/s with corresponding shear Reynolds numbers between 560 and 1630. In the viscous sublayer, the probability density distributions of stream- and span-wise wall shear stress (WSS) components could be reliably captured down to probability densities of 10E−3. As far as we know, this has not been achieved in the past, particularly not for the span-wise component. For the stream-wise component the measured Reynolds-number dependency of the root mean squared fluctuations agrees to correlations by Örlü & Schlatter (2011). Furthermore, the skewness of the stream-wise WSS agrees well to values from DNS. On the other hand, the span-wise WSS fluctuations consistently underestimate the predicted DNS values, for which it is assumed that the deviation can be explained by the rapid decrease of the span-wise velocity fluctuations with increasing wall distance. Wall-normal profiles of 3c velocity statistics were obtained by bin averaging of particle velocities. Up into the buffer layer, these profiles agree well with profiles from stereo PIV as well as from DNS and LES, indicating an accurate determination of both near-wall velocities and inner scaling.

Miniaturized high signal-to-noise ratio optical air data system using a compact multi-axis parallel transceiver for airborne application

We have developed a miniaturized multi-channel parallel optical air data system with high signal-to-noise ratio for airborne application. In the system, we designed a fiber amplifier with multi-channel high-energy output that was respectively used as the transmitting signals and a compact multi-axis transceiver with an entrance pupil diameter of 70 mm that was used to receive multi-channel signals simultaneously. We demonstrated the performance of our system both on ground and on board. On ground, the measured line-of-sight speed had an average error of 0.02 m/s and a standard deviation of 0.15 m/s. On board, the standard deviation between the true air speed, angle of attack, and angle of sideslip measured by our system and a commercial Swiss air data system was 1 kt, 0.68°, and 0.54°, respectively, and those standard deviation between our system and a system with the same design but employing multiple single-axis telescopes with entrance pupil diameter of 30 mm was 0.34 kt, 0.36°, and 0.28°, respectively. The signal-to-noise ratio of our system was 4.5 times higher than that of the system with small single-axis telescopes. Our system is very promising for airborne applications because of its small volume, high signal-to-noise ratio, and high data rate.

Designed 3D Dumpling‐Shaped Femtosecond Laser Structured Light Field for Nanoscale Sensing

AbstractNanoscale optical sensing plays a crucial role in achieving high‐precision non‐contact distance and displacement measurements. As one of the promising alternatives, structured light can greatly simplify optical sensing systems. In this study, a novel optical phenomenon of a structured beam called the “Dumpling‐shaped Structured Light Field” (DSLF) is revealed, which forms during the focusing of cylindrical lens beams. The 3D DSLF comprises two mutually perpendicular primary and secondary foci, offering unique possibilities in micro/nano processing and sensing applications. A thorough investigation of the DSLF is conducted, revealing a correlation between the secondary foci and the phase status at the objective lens's entrance pupil. The propagation of DSLF under tight focus conditions has been verified and discussed through methods of femtosecond laser two‐photon polymerization and light field analysis. Finally, thanks to the unique 3D intensity distribution of 3D DSLF, the applicability of DSLF in high‐precision position and vibration sensing has been demonstrated. By detecting the horizontal and vertical dimensions of the reflected DSLF, position and vibration sensing is achieved with a Z‐direction accuracy of 10 nm (λ/80). This research contributes to understanding structured light, and offers practical applications in various fields, including micro/nano laser processing, optical imaging, sensing, etc.

Features of Adaptive Phase Correction of Optical Wave Distortions under Conditions of Intensity Fluctuations

An analysis of the features of measurements and correction of phase distortions in optical waves propagating in the atmosphere at various levels of turbulence was performed. It is shown that with increasing intensity fluctuations, the limiting capabilities of phase correction decrease, and the phase of an optical wave that has passed through a turbulence layer consists of two components: potential and vortex. It was found that even in the region of weak fluctuations there is an overlap of spectral filtering functions for intensity and phase fluctuations. Areas of turbulence inhomogeneities have been identified that will have mutual influence and negatively affect the operation of the phase meter. It is noted that correlation functions, both phase and intensity, are less susceptible to this compared to structural functions. The results of experimental studies on the reconstruction of the wavefront of laser radiation distorted by atmospheric turbulence using a Shack–Hartmann wavefront sensor during vignetting and central screening of the entrance pupil in the optical system are presented. Studies have been carried out on the propagation of laser radiation along a horizontal atmospheric path for various levels of turbulence. The results are analyzed in terms of Zernike polynomials.

Integral field spectroscopy supports atmospheric optics to reveal the finite outer scale of the turbulence

The spatial coherence wavefront outer scale ( characterizes the size of the largest turbulence eddies in Earth's atmosphere, determining low spatial frequency perturbations in the wavefront of the light captured by ground-based telescopes. Advances in adaptive optics (AO) techniques designed to compensate for atmospheric turbulence emphasize the crucial role of this parameter for the next generation of large telescopes. The motivation of this work is to introduce a novel technique for estimating \ from seeing-limited integral field spectroscopic (IFS) data. This approach is based on the impact of a finite \ on the light collected by the pupil entrance of a ground-based telescope. We take advantage of the homogeneity of IFS observations to generate band filter images spanning a wide wavelength range, enabling the assessment of image quality (IQ) at the telescope's focal plane. Comparing the measured wavelength-dependent IQ variation with predictions derived from a first-order analytical approach based on turbulence statistics simplifications using the von Kármán model provides valuable insights into the prevailing \ parameter during the observations. We applied the proposed technique to observations from the Multi-Unit Spectroscopic Explorer (MUSE) in the wide-field mode obtained at the Paranal Observatory. Our analysis successfully validates the first-order analytical expression, which combines the seeing ($ $) and the \ parameters, to predict the IQ variations with the wavelength in ground-based astronomical data. However, we observed some discrepancies between the measured and predictions of the IQ that are analyzed in terms of uncertainties in the estimated $ $ and dome-induced turbulence contributions. This work constitutes the empirical validation of the analytical expression for estimating IQ at the focal plane of ground-based telescopes under specific $ $ and finite \ conditions. Additionally, we provide a simple methodology to characterize the \ and dome-seeing ($ dome $) as by-products of IFS observations routinely conducted at major ground-based astronomical observatories.

Evaluation of corneal power from an AS-OCT thick lens model and ray tracing: reliability of the keratometer index

Purpose: To investigate and compare different strategies of corneal power calculations using keratometry, paraxial thick lens calculations and ray tracing. Setting: Tertiary care center. Design: Retrospective single-center consecutive case series. Methods: Using a dataset with 9780 eyes of 9780 patients from a cataractous population the corneal front (Ra/Qa) and back (Rp/Qp) surface radius/asphericity, central corneal thickness (CCT), and entrance pupil size (PUP) were recorded using the Casia 2 tomographer. Beside keratometry with the Zeiss (PKZ) and Javal (PKJ) keratometer index, a thick lens paraxial formula (PG) and ray tracing (PR) was implemented to extract corneal power for pupil sizes from 2 mm to 5 mm in steps of 1 mm and PUP. Results: With PUP PKZ/PKJ overestimates the paraxial corneal power PG in around 97%/99% of cases and PR in around 80% to 85%/99%. PR is around 1/6 or 5/6 diopters (D) lower compared with PKZ or PKJ. For a 2 mm pupil PR is around 0.20/0.91 D lower compared with PKZ/PKJ and for a 5 mm pupil PR is comparable with PKZ (around 0.03 D lower) but around 0.70 to 0.75 D lower than PKJ. Conclusions: “True” values of corneal power are mostly required in lens power calculations before cataract surgery, and overestimation of corneal power could induce trend errors in refractive outcome with axial length and lens power if compensated with the effective lens position.

Multi-Channel Hyperspectral Imaging Spectrometer Design for Ultraviolet Detection in the Atmosphere of Venus

The spectroscopic detection of SO2 and unknown UV absorber substance in the H2SO4 cloud layer of Venus’ atmosphere is currently a focal point in the study of the habitability of Venusian atmospheric clouds. This paper addresses the simultaneous detection requirements of multiple substances in the ultraviolet range of Venus’ atmosphere and proposes a multi-channel hyperspectral imaging system design using pupil separation prisms and grating multilevel spectra. The system achieves a multi-channel design by splitting the entrance pupil of the telescope using prisms. Spectra from different channels are diffracted to the same detector through different orders of the grating. The system features a single spectrometer and detector, enabling simultaneous detection of spectra from different channels. It also boasts advantages such as compact size, ultra-high spectral resolution, and simultaneous multi-channel detection. The system design results indicate that within the working spectral range of three channels, the spectral resolution is better than 0.15 nm, surpassing previous in-orbit or current in-orbit planetary atmospheric detection spectrometers. With a Nyquist frequency of 56 lp/mm, the full-field MTF exceeds 0.7. The system’s smile is less than 0.05 μm, and the keystone is less than 0.04 μm, meeting the requirements for imaging quality.

Optical design of a visible/short-wave infrared common-aperture optical system with a long focal length and a wide field-of-view.

Addressing the urgent need for long-distance dim target detection with a wide field-of-view and high sensitivity, this paper proposes a visible and short-infrared dual-band common-aperture optical system characterized by a broad field and extended focal length. To achieve system miniaturization and high-sensitivity target detection, the visible and infrared optical systems share a Ritchey-Chretien primary and secondary mirror. The primary optical path is segmented into visible light (0.45-0.75µm) and short-wave infrared (SWIR) (2-3µm) bands by a dichroic spectral splitter prism. The SWIR optical system utilizes four short-wave cooled infrared detectors, and wide-field stitching is achieved using a field-of-view divider. While ensuring the high cold-shield efficiency of cooled infrared detectors, this common-aperture optical system delivers visible and SWIR dual-band images with expansive fields, elongated focal lengths, and sizable apertures. The visible-light optical system has a focal length of 277mm, a field-of-view of 2.3∘×2.3∘, and an entrance pupil diameter of 130mm. Meanwhile, the SWIR optical system features a focal length of 480mm, a field-of-view of 2.26∘×1.8∘ and an entrance pupil diameter of 160mm. The design outcomes suggest that the imaging quality of the optical system approaches the diffraction limit. This visible/SWIR common-aperture optical system exhibits high sensitivity, a large field-of-view, compact structure, and excellent imaging quality, thereby meeting the requirements for long-distance dim target detection and imaging.

Overcoming the diffraction limit by exploiting unmeasured scattering media

Scattering is not necessarily an obstacle to imaging. It can help enhance imaging performance beyond the reach of a lens system. However, current scattering-enhanced imaging systems require prior knowledge of the transmission matrix. There are also some techniques that do not require such prior knowledge to see through strongly scattering media, but the results are still limited by the optics used. Here we propose overcoming the diffraction limit through a visually opaque diffuser. By controlling the distance between the diffuser and lens system, light with higher spatial frequencies is scattered into the entrance pupil. With the deformed wavefront corrected, we experimentally achieved imaging with 3.39× enhancement of the Rayleigh limit. In addition, our method works well for objects that are 4× larger than the memory effect range and can maintain super-resolution performance for a depth of field 6.6× larger than a lens can achieve. Using our method, an obstructive scattering medium can enhance the throughput of the imaging system, even though the transmission matrix of the scattering medium has not been measured beforehand.