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Lobster eye micro pore optics has been extensively researched, developed, and experimented with over the past few decades since its proposal by Angel in 1979. The lobster eye X-ray telescope represents the next generation of X-ray time-domain astronomy. This study presents a novel semi-analytical numerical model for simulating and studying the optical performance of micro pore X-ray optics based on geometric physical models, channel errors, and Fresnel reflectance. The numerical method accurately and rapidly models the X-ray point-spread function through millions of square microchannels. Soft X-ray testing validates the semi-analytical numerical model, which simulates common channel errors in lobster eye optics manufacturing. The X-ray results demonstrated that tilt and shear channel errors significantly impacted the point spread function, which is consistent with simulation outcomes and has a significant guiding value for the subsequent process improvement. • The optical properties of the lobster eye micro pore optics were characterized and measured in detail. • We propose a novel semi-analytical numerical model for studying the performance of micro pore optics. • The Tilt and Shear channel errors significantly impacted the point spread function of lobster eye optics. [ABSTRACT FROM AUTHOR]

Conformal optics arose from the need for better aerodynamic performance. The Haack curve has the lowest air drag under given conditions. It has superior aerodynamic properties compared to hemispherical domes and quadric conformal domes. Most in line with the concept of conformal optics. But aberration correction is also the most difficult. At present, there is no research on this conformal dome with the best aerodynamic performance. Therefore, a new design method for the internal surface is proposed in this paper to reduce the fluctuation range of aberrations. This method can eliminate the position error on the detector, reduce the fluctuation range of coma and spherical aberration, and even suppress the sensitivity of the defocus-field curvature to the parameters change. A condition for eliminating astigmatism is also proposed for the conformal dome. The fluctuation range of astigmatism and the difficulty of corrector design are reduced by reasonably choosing the rotation center. The research of this paper is of great significance in improving the aerodynamic performance of conformal optical systems. • The aberration correction method for the Haack conformal dome is proposed, which has never been studied before. • An internal surface design method is proposed to eliminate the position error of the detector and reduce the aberration. • The rotation center of the smallest astigmatism fluctuation in the asymmetric conformal optical systems is derived. [ABSTRACT FROM AUTHOR]

The finite depth of focus (DOF) of a focusing lens gives rise to the degradation of lateral resolution at defocused positions. Consequently, the generation of a needle-shaped beam with sub-diffraction size and extended DOF can break through this limitation, but few studies have effectively balanced these two characteristics. In this paper, we propose a method based on the stochastic parallel gradient descent (SPGD) algorithm for designing multi-ring diffractive optical elements (DOEs) to produce the needle-shaped beam, which maintains a super-resolution and uniform spot within a large extended DOF range. Numerical simulations and experimental results have validated that our method can extend the DOF by 14 times longitudinally and reduce the lateral resolution to 73% of Airy spot, while maintaining up to 92% uniformity of the beam diameter. Furthermore, we demonstrate that the DOF of the needle-shaped beam extends with the increase of the number of rings and phase levels within the DOE. Our work provides an effective strategy for the design of DOF-extended DOE and it is anticipated to find potential applications in microscopy and three-dimensional imaging, photolithography, and optical manipulation. • Needle-shaped beam with super-resolution spot and large depth of focus. • Stochastic parallel gradient descent algorithm based optimization for diffractive optics. • Extremely high uniformity of the beam diameter within the extended depth of focus range. • Tunability of the needle-shaped beam through varying parameters within the diffractive optical element. [ABSTRACT FROM AUTHOR]

Quantitative characterization of blood cells is very important for medical diagnosis and life science research. This study presents a novel label-free and high-throughput approach for analyzing flowing blood cells in a microfluidic channel by combining deep learning with partially coherent illumination-based diffraction phase microscopy (PCI-DPM). Diluted blood was injected into a microchannel and imaged with PCI-DPM, yielding high-contrast phase images for the blood cells. A modified YOLOv5-s neural network was used to perform automatic identification and analysis of blood cells in the phase image of PCI-DPM, revealing the diameter, dry mass, volumetric density, and speed of blood cells precisely. The proposed approach allows quick and accurate assessment of blood samples, providing valuable insights for patients in different pathological states, such as hematological disorders and infections. [ABSTRACT FROM AUTHOR]

In a recent article Babiker et al. (2024) claim that cylindrical vector beams (CVBs), also referred to as higher-order Poincaré (HOP) beams, possess optical chirality densities which exhibit 'superchirality'. Here we show that, on the contrary, CVBs possess less optical chirality density than a corresponding circularly polarized scalar vortex beam and that the 'superchiral' results are nonphysical. We also identify a number of issues concerning the derivation and general theory presented. [ABSTRACT FROM AUTHOR]

The lobster eye lens uses square channels to reflect and converge light. It has no fixed optical axis and possesses advantages such as a broad field of view (FOV) and no chromatic aberration. Moreover, lobster eye lenses based on microporous optics manufacturing technology have been successfully applied to the spatial detection of soft X-ray spectra. Based on the penetrability of hard X-rays, lobster eye lenses can detect the perspective of hidden targets, which can be applied to fields such as safety inspection and industrial flaw detection. This study proposes an algorithm for comprehensive analysis of the imaging ability of a hard X-ray lobster eye lens, focusing on the stray rays transmitted by high-penetration X-rays. The simulation results showed that the point-spread function of the off-axis FOV is different. With the increase in the photon energy, the enhanced superposition effect of the cross-arm decreases the image contrast. Both the simulated and experimental images show that the image contrast decreases as the photon energy increases. The image contrast can be improved by adding more Pb to the materials used to create the lobster eye lens owing to the strong attenuation ability of Pb to X-rays. These results can contribute to the improvement of lobster eye lenses in X-ray backscatter imaging. • Lobster eye lenses can detect the perspective of hidden targets using hard X-rays. • We analyse imaging of a large-field-of-view hard X-ray lobster eye lens. • The analysis focuses on the stray light transmitted by high-penetration X-rays. • The image contrast can be improved by adding more Pb. • Findings contribute to improving lobster eye lenses in X-ray backscatter imaging. [ABSTRACT FROM AUTHOR]

The advancement of lithography, mass spectrometry and other technologies is increasingly requiring the high-quality focusing of extreme ultraviolet (EUV) beams. Traditional transmissive optics are not suitable for focusing EUV beams due to the strong absorption of most materials. However, rapid developments of metasurfaces have led to breakthroughs in the research of EUV metalenses. Based on the hole-type unit structure proposed recently, we demonstrated the dual-wavelength achromatic metalens in the EUV working for wavelengths of 46.9 and 69.8 nm with a numerical aperture 0.05. Then the dispersion manipulation for the achromatic metalens is extended to three wavelengths 46.9, 60, and 69.8 nm. The simulation results suggest that the maximum relative focal shift from the designed focal length is 0.008 %, and the diffraction-limit focusing is achieved for all working wavelengths. This work could expand the means of the EUV optical field modulation. • Transmissive EUV metalens is designed for beam focusing. • The dual-wavelength achromatic metalens is demonstrated. • The dispersion manipulation for the metalens is extended to three wavelengths. [ABSTRACT FROM AUTHOR]

The laser-induced damage observed in optics has rendered compressor grating the most limited component in petawatt (PW) lasers, owing to the considerable challenges associated with manufacturing gratings possessing both a sufficiently high damage threshold and large dimensions. An asymmetric four-grating compressor (AFGC) based multistep pulse compressor method was proposed recently to alleviate the requirement of such gratings. The viability of AFGC is further investigated experimentally in SEL-100 PW frontend with spectral bandwidth of over 200 nm in this study. It is verified that the AFGC has the ability of beam-smoothing resulting from the introduced spatial dispersion. Meanwhile, the spatial dispersion scarcely impacts temporal contrast and focal spot of the output beam. By reducing the laser spatial intensity modulations from 2.0 to 1.3, the pulse energy capacity of the AFGC can be increased by more than 1.5 times through simple translation. The results mark a breakthrough toward experimentally renovating the grating compressor, and pave the way for a reliable and efficient constructions of 100 s PW lasers. [ABSTRACT FROM AUTHOR]

А 3D CFD model coupled with wave optics model for laser beam propagation is used to calculate the performance of a hydrocarbon-free K end pumped flowing-gas diode pumped alkali amplifier (DPAA). The K DPAA efficiency and output beam quality were calculated as a function of various parameters and the results were compared with those calculated for end pumped Rb DPAA with hydrocarbon-free buffer gas. For moderate pump intensity, both the efficiency and beam quality deteriorate at low gas velocity. The efficiency strongly depends on the pressure of the buffer helium, reaching a maximum at pressure close to atmospheric and falling with a further increase in pressure. The maximum efficiency of the K DPAA (∼0.45) is approximately 4 times higher than that of the Rb one, achieved at the same optimal pump power of 5 kW. Addition of CH 4 to the He buffer in the K DPAA decreases the amplifier efficiency and reduces the beam quality. [ABSTRACT FROM AUTHOR]

Solitons have been the focus of intense research since their discovery in the nineteenth century and have revolutionized various fields of science and technology, leading to groundbreaking advancements in nonlinear dynamics, optics, communications, and other disciplines. As we are commemorating the 50th anniversary of the discovery of optical solitons, this article aims to provide the contributions of the scientific community in India towards advancement in this domain, shedding light on the fundamental properties, and applications of solitons through diverse theoretical models and analytical approaches in different physical systems, such as in optical fibers, Bose–Einstein condensates, plasma etc. This article is a tribute to the late Prof. Porsezian, a pioneering figure in the world of 'Optical Soliton'. This article is a compendium of notable scientific contributions from the Indian community to the field of Soliton Physics. ▪ • It's a tribute to the late Prof. Porsezian for his contribution to soliton research. • It intends to showcase Indian community's major contributions in soliton research. • Breakthroughs and notable works across the globe, mainly from India was highlighted. • Various solitons, from fibers to diverse media, were discussed in this article. [ABSTRACT FROM AUTHOR]