- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Control of the creation of bottle-hollow beam by polarization shaping
摘要： We propose a method for generating bottle-hollow (BH) beams by tailoring the polarization state of the incident field in a tightly focused system. An optical BH field can be generated in the vicinity of the focus by tailoring azimuthal and radial polarization indices of the incident field. Calculations show that the length and diameter are mainly affected by the radial polarization index. While for the azimuthal index, it affects the width of the hollow greatly. As a result, an all-optical controlled tunable BH beam is achieved. The generated BH beam may find application in optical tweezers.
关键词： Diffractive optics,Singular optics.,Polarization,Propagation
更新于2025-09-23 15:23:52
-
Laguerre–Gauss and Hermite–Gauss soft X-ray states generated using diffractive optics
摘要： Light’s capacity to carry angular momentum is integral to our knowledge of physics and ability to probe matter. In addition to spin, photons can occupy free-space orbital angular momentum eigenstates. Visible light orbital angular momentum is used in quantum information experiments, super-resolution microscopy, optical tweezers and angular momentum transfer to atoms in optical lattices. Soft X-ray orbital angular momentum applications, slowed by the lack of suitable optics and the rarity of coherent X-ray sources, could enable the direct alteration of atomic states through orbital angular momentum exchange, and methods to study the electronic properties of quantum materials. We have made soft X-ray diffractive optics that generate single Laguerre–Gauss modes, observed carrying up to 30? angular momentum per photon, or their superpositions. We also present Hermite–Gauss diffractive optics and a soft X-ray orbital angular momentum analyser. These tools could enable both the manipulation and finer characterization of topologically complex electronic matter, such as magnetic skyrmions.
关键词： Hermite–Gauss modes,Diffractive optics,Laguerre–Gauss modes,Soft X-ray,Orbital angular momentum
更新于2025-09-23 15:22:29
-
Deflecting transmissive light beams with metasurfaces based on crystalline silicon high-contrast grating
摘要： Dielectric metasurfaces have emerged and expanded rapidly for their success in realizing high-efficiency wavefront control in the optical and infrared ranges. However, devices have either been demonstrated at near-infrared regime using high-index semiconductors such as silicon, or they use lower index dielectric materials such as TiO2 or Si3N4 and operate in the visible wavelength regime to avoid the optical loss of dielectric materials. It seems that dielectric metasurfaces could not achieve either high index or high device efficiency, simultaneously. Here, we provide a crystalline silicon metasurface scheme to efficiently modulate transmitted light beams at the wavelengths as short as to 532 nm. The unit cell of the metasurfaces consists of high-contrast grating (HCG), which provides full 2π phase control for circular polarized incident beams in thin film. The demonstration of HCG deflector shows that the device enables high deflecting efficiency as high as those made by transparent materials. Our results provide a paradigm to functionalize transmitted light beams based on crystalline silicon in the visible wavelength regime.
关键词： dielectric metasurfaces,high-contrast grating,diffractive optics,crystalline silicon
更新于2025-09-23 15:19:57
-
Generating autofocused aberration laser beams with different spectral performance
摘要： We present a flexible approach for generating autofocused aberration laser beams (ALBs) of different wavelengths based on the diffractive optical element (DOE) design with distinct phase transmittance that has radial power q and periodic angular dependence sin(mφ). The diffraction pattern of ALBs strongly depends on the periodic angular power controlled phase of the DOE. During free-space propagation, the ALBs with different wavelengths convert into different light distributions that have mth-order symmetry (for odd m) and 2mth-order symmetry (for even m). The ALBs exhibit autofocusing properties that significantly differ at longer wavelengths relatively with smaller wavelengths. The formation of light intensity distributions in free-space propagation has a sharp focusing feature that strongly depends on the radial power q. The numerically simulated results are presented for wavelengths in the infrared, visible, and ultra-violet regimes. The experimental findings measured at a wavelength of λ = 1064 nm, show good agreement with the numerically simulated results and thus verifying our approach.
关键词： propagation,laser beam shaping,diffractive optics
更新于2025-09-16 10:30:52
-
Fabrication of diamond diffractive optics for powerful CO2 lasers via replication of laser microstructures on silicon template
摘要： New approach to fabricate diamond diffractive optical elements (DOEs) with continuous relief for powerful CO2 lasers is proposed and tested. It involves short-pulse laser microstructuring of a silicon wafer, which further is used as a substrate for polycrystalline diamond growth in a microwave plasma-assisted CVD process. After fine mechanical polishing of the growth side of the diamond film, the silicon substrate is removed via chemical etching. Two different DOEs providing close to 100% diffraction efficiency were fabricated with this technique: cylindrical Fresnel lens with kinoform surface profile and three-beam splitter with continuous microrelief. Optimization of the laser processing conditions has made possible to reduce the final roughness of the structured diamond surface to 200-400 nm depending on the local relief depth (0-7 μm). Both DOEs tested with a CO2 laser have demonstrated high transparency and diffraction efficiency, as well as low radiation scattering of the IR radiation at the surface irregularities.
关键词： laser microstructuring,diffraction efficiency,CVD process,diamond diffractive optics,CO2 lasers,silicon template
更新于2025-09-12 10:27:22