Ultrawide and unidirectional enhancements of a photonic spin Hall effect in a tilted uniaxial crystal.

Since the enhancement of the photonic spin Hall effect (PSHE) is limited around the Brewster's angle, the scientific problem of how to extend the range of incident angles and to keep them unidirectional for the enhanced PSHE remains open. Here, we propose an effective method to achieve the ultrawide angle and unidirectional enhancement of PSHE via the omnidirectional Brewster's effect in a tilted uniaxial crystal. By properly setting the permittivity and the optical axial angle of the uniaxial crystal, the omnidirectional Brewster's effect can be obtained to realize an ultrawide angle enhancement of the PSHE. Then, by appropriately deviating the optical axial angle, the ultrawide enhancement of the PSHE can be achieved within the maximum incident angle range of 60° with unchanged direction. These findings inspire an unprecedented route to facilitate the applications in precision measurement and spin-dependent devices.

1.7†µm sub-200 fs vortex beams generation from a thulium-doped all-fiber laser.

The pulsed 1.7 µm vortex beams (VBs) has significant research prospects in the fields of imaging and material processing. We experimentally demonstrate the generation of sub-200 fs pulsed VBs at 1.7 µm based on a home-made mode-selective coupler (MSC). Through dispersion management technology in a thulium-doped fiber laser, the stable linearly polarized VBs pulse directly emitting from the cavity is measured to be 186 fs with central wavelength of 1721.2 nm. By controlling the linear superposition of LP11 modes, cylindrical vector beams (CVBs) can also be obtained. In addition, a variety of bound states pulsed VBs at 1.7 µm can also be observed. Our finding provides an effective way to generate ultrashort pulsed VBs and CVBs at 1.7 µm waveband.

Genotype Impacts Axial Length Growth in Pseudophakic Eyes of Marfan Syndrome.

Purpose: The purpose of this study was to investigate the relationship between axial length (AL) growth and FBN1 genotype in patients with Marfan syndrome (MFS) after lens surgery and customize the selection of intraocular lens (IOL) power. Methods: Patients with MFS who had lens surgery and primary IOL implantation received panel-based next-generation sequencing (NGS). The rate of axial length growth (RALG) was calculated using pre- and postoperative AL measurements and corrected log10-transformed age. A multivariable regression model of RALG was developed after analyzing the effect of FBN1 genotypes and confounding factors. Results: A total of 139 probands of MFS with a median age at lens surgery of 6.25 years (interquartile range [IQR] = 4.67, 12.50 years) were followed up for a median duration of 2.08 years (IQR = 1.16, 3.00 years). The AL growth curve between the age of 3 and 15 years old was logarithmic. Dominant-negative (DN) variants affecting the disulfide-bridge forming cysteines and the conserved residues for calcium-binding had significantly higher RALG than DN variants affecting other structures (P = 0.001) but comparable to that of haplo-insufficiency variants (P = 1.000). Pre-operative AL (b = 0.563, P = 0.011) and genotype constant (b = 2.603, P = 0.011) were significantly associated with RALG in the final model. A Python-based calculator, Marfan IOL Calculator version 2.0, was programmed using the RALG to predict postoperative AL and customize IOL selection based on the ocular biometric parameters and FBN1 genotype. Conclusions: FBN1 genotype impacted the growth of AL in patients with MFS after IOL implantation. Knowing the FBN1 genotype could help cataract surgeons to customize IOL selection.

Generalized Brewster angle-enhanced photonic spin Hall effect in an all-dielectric metasurface.

The enhancement of the photonic spin Hall effect (PSHE) is usually limited at horizontally polarized incidence and around the nonadjustable Brewster angle. In this Letter, a flexible method for enhancing the reflective PSHE with tunable incident angle under both vertically (V) and horizontally (H) polarized light has been theoretically explored. By using the multipole decomposition method, the variable generalized Brewster angle (GBA) is proven to be obtained under both V- and H-polarized light at different wavelengths in the all-dielectric metasurface. Then, owing to the large ratio of Fresnel coefficients at the GBA, the enhancement of PSHE in this Letter can not only be available for both V- and H-polarization, but also achieved at widely tunable incident angle and different operating wavelengths in the same metasurface. This work provides a simple method to achieve the flexible enhancement of PSHE and offers a novel way for designing a functional spin-based photonic device.

Thickness-dependent in-plane shift of photonic spin Hall effect in an anisotropic medium.

As the in-plane spin splitting (IPSS) has a broad application for the precision measurement and sensing, it is extremely important to explore its enhancement mechanism via the photonic spin Hall effect (PSHE). However, for a multilayer structure, the thickness in most of previous works is generally set as a fixed value, lacking the deeply exploration of the influence of thickness on the IPSS. By contrast, here we demonstrate the comprehensive understanding of thickness-dependent IPSS in a three layered anisotropic structure. As thickness increases, near the Brewster angle, the enhanced in-plane shift exhibits a thickness-dependently periodical modulation, besides with much wider incident angle than that in an isotropic medium. While near the critical angle, it becomes thickness-dependently periodical or linear modulation under different dielectric tensors of the anisotropic medium, no longer keeps almost constant in an isotropic medium. In addition, as exploring the asymmetric in-plane shift with arbitrary linear polarization incidence, the anisotropic medium could bring more obvious and wider range of thickness-dependently periodical asymmetric splitting. Our results deepen the understanding of enhanced IPSS, which is expected to promise a pathway in an anisotropic medium for the spin control and integrated device based on PSHE.

Predicting axial length in patients with Marfan syndrome and ectopia lentis after modified capsular tension ring and intraocular lens implantation.

PURPOSE: To predict the growth of axial length (AL) in patients with Marfan syndrome (MFS) and ectopia lentis (EL). SETTING: Eye and ENT Hospital of Fudan University, Shanghai, China. DESIGN: Consecutive retrospective case series. METHODS: Eyes were evaluated that had modified capsular tension ring and intraocular lens (IOL) implantation. The rate of AL growth (RALG) was calculated using AL divided by log10-transformed age. A multivariate linear regression model of RALG was developed after validation. RESULTS: 128 patients with MFS and EL were enrolled with a median follow-up duration of about 3 years. RALG was independent of age between 3 years and 15 years old ( P = .799) and decreased to 0 thereafter ( P = .878). Preoperative AL was associated with RALG in patients under 15 years old ( P = .003). Beta values for the final model of RALG were as below: intercept (-9.794) and preoperative AL (0.664). The postoperative AL was predicted as: postAL = preAL + RALG × log 10 ([postAge + 0.6]/[preAge + 0.6]). The mean prediction error was -0.003 (95% CI, -0.386 to 0.3791) mm and the mean absolute percentage error was 1.93% (95% CI, 0.73% to 3.14%). A Python-based calculator was developed to use the predicted AL in selecting IOL power and setting undercorrection. CONCLUSIONS: The AL growth of patients with MFS followed a logarithmic pattern and ceased at about age 15. A prediction model of postoperative AL was established for individual MFS patients between 3 and 15 years old, which could potentially optimize the IOL power selection.

Optimal weak measurement in the photonic spin Hall effect for arbitrary linear polarization incidence.

The photonic spin Hall effect (SHE) has great potential in precision metrology due to its unique spin modulation characteristics. To improve its potential, the effective enhancement of detection precision has become an important issue. In this work, we theoretically and experimentally demonstrate the optimal weak measurement (optimal overlap of pre-selected and post-selected states) with arbitrary linear polarization incidence for both amplified transverse and in-plane shift. Also, based on photonic SHE, a method for arbitrary linear polarization angle detection is then proposed experimentally with a detection accuracy of 0.04 degree. It can provide a guidance for the weak measurement and enlarge the potential application of photonic SHE in field of precision measurement.

High energy switchable pulsed High-order Mode beams in a mode-locking Raman all-fiber laser with high efficiency.

High energy pulsed High-order Mode (HOM) beams has great potential in materials processing and particle acceleration. We experimentally demonstrate a high energy mode-locking Raman all-fiber laser with switchable HOM state. A home-made fiber mode-selective coupler (MSC) is used as the mode converter with a wide bandwidth of 60 nm. By combining advantages of MSC and stimulated Raman scattering, 1.1 µJ pulsed HOM beams directly emitting from the all-fiber cavity can be achieved. After controlling the category and phase delay of vector modal superposition, different pulsed HOM beams including cylindrical vector beams (CVBs) (radial and angular) and optical vortex beams (OVBs) are reasonably obtained with high purity (all over 95%), as well as arbitrary switching. Furtherly, the slope efficiency of HOM beams in the mode-locking and continuous wave operations are as much as 20.3% and 31.8%, respectively. It may provide an effective way to achieve high energy pulsed HOM beams.

Enhanced photonic spin Hall effect via singularity induced by destructive interference.

In this work, we report a simple and effective method for enhancing the photonic spin Hall effect (SHE) via singularity induced by destructive interference in an ultrathin uniaxial slab. Deriving from anisotropy, the incident angles corresponding to destructive interference for p- and s-polarized waves will be deviated, leading to an enhancement peak in transverse spin shift. Interestingly, by adjusting the thickness of slab, the destructive interference and the Brewster effect can act together. At this point, the photonic SHE exhibits great singularity, and the maximum transverse spin shift can approach about three times more than that of the Brewster effect acting alone. This Letter reveals the influence of the interference effect on photonic SHE in layered media and provides a simple way to achieve enhanced photonic SHE.