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Femtosecond laser additive and subtractive micro-processing: enabling a high-channel-density silica interposer for multicore fibre to silicon-photonic packaging
摘要： Great strides have been made over the past decade to establish femtosecond lasers in advanced manufacturing systems for enabling new forms of non-contact processing of transparent materials. Research advances have shown that a myriad of additive and subtractive techniques is now possible for flexible 2D and 3D structuring of such materials with micro- and nano-scale precision. In this paper, these techniques have been refined and scaled up to demonstrate the potential for 3D writing of high-density optical packaging components, specifically addressing the major bottleneck for efficiently connecting optical fibres to silicon photonic (SiP) processors for use in telecom and data centres. An 84-channel fused silica interposer was introduced for high-density edge coupling of multicore fibres (MCFs) to a SiP chip. Femtosecond laser irradiation followed by chemical etching (FLICE) was further harnessed to open alignment sockets, permitting rapid assembly with precise locking of MCF positions for efficient coupling to laser written optical waveguides in the interposer. A 3D waveguide fanout design provided an attractive balancing of low losses, mode-matching, high channel density, compact footprint, and low crosstalk. The 3D additive and subtractive processes thus demonstrated the potential for higher scale integration and rapid photonic assembly and packaging of micro-optic components for telecom interconnects, with possible broader applications in integrated biophotonic chips or micro-displays.
关键词： multicore fibre,waveguide fanout,silicon photonics interposer,space-division multiplexing,fibre socket,femtosecond laser micro-processing,photonic packaging
更新于2025-09-23 15:19:57
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Polarization Multiplexing Terahertz Metasurfaces through Spatial Femtosecond Lasera??Shaping Fabrication
摘要： Terahertz (THz) metasurface has emerged as a powerful technique to fully modulate the wavefronts of THz radiation. To improve the information storage capability and enhance the encryption security of THz metasurface holograms, smart metasurface designs, and fabrications for polarization multiplexing are essential. In this study, two kinds of polarization multiplexing THz metasurfaces are fabricated through the slit-based spatial modulation of femtosecond laser. Controllable elliptical aperture arrays can easily and flexibly be fabricated on gold films by adjusting the width and position of the slit combined with the laser pulse energy. Based on the Pancharatnam–Berry phase and amplitude modulation, respectively, THz metasurfaces, with two independent target phases or amplitude profiles, are obtained. A variety of information can be processed under different polarization states through these THz metasurfaces. This method allows flexible and efficient customization of THz metasurfaces because of the high-speed fabrication and reproducibility as well as precise control of elliptical apertures location on the surface.
关键词： spatial shaping,THz metasurface,femtosecond laser fabrication,polarization multiplexing
更新于2025-09-23 15:19:57
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Comparison of astigmatism correction between anterior penetrating and intrastromal arcuate incisions in eyes undergoing femtosecond lasera??assisted cataract surgery
摘要： To compare the safety, efficacy, and predictability of femtosecond laser–enabled anterior penetrating and intrastromal arcuate incisions for the correction of preoperative astigmatism at the time of cataract surgery.
关键词： anterior penetrating incisions,femtosecond laser,cataract surgery,astigmatism correction,intrastromal incisions
更新于2025-09-23 15:19:57
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Femtosecond laser fabrication of LIPSS-based waveplates on metallic surfaces
摘要： A fast and reliable method for the fabrication of polarization modifying devices using femtosecond laser is reported. A setup based on line focusing is used for the generation of LIPSS on stainless steel, processing at different speeds between 0.8 and 2.4 mm/s with constant energy per pulse of 1.4 mJ. SEM and AFM characterizations of the LIPSS show a progressive increase in period as the processing speed increases, while height remains approximately constant in the studied range. Optical characterization of the devices shows an induced change in the polarization of the reflected beam that varies with the processing speed, which allows a controlled fabrication of these devices.
关键词： polarization,waveplate,femtosecond,laser,LIPSS,nanostructure
更新于2025-09-23 15:19:57
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Controllable photon energy deposition efficiency in laser processing of fused silica by temporally shaped femtosecond pulse: Experimental and theoretical study
摘要： Photon energy deposition plays a crucial role in femtosecond laser irradiation followed by chemical etching processing, which is an emerging technique for the better control of micro/nano structures on fused silica. In this study, we have experimentally and theoretically studied the controllable photon energy deposition in laser irradiation of fused silica by temporally shaped femtosecond laser pulse trains. The experimental result shows that the photon energy deposition efficiency could be either reduced or enhanced by adjusting the total fluence of shaped pulse trains. Furthermore, the sub-pulse interval and intensity ratio of temporally shaped pulse trains were revealed to play a critical role in photon energy deposition. The corresponding experimental observations are qualitatively explained by a plasma model that considers the free electron generation processes and corresponding feedback on the photon energy deposition.
关键词： Photon energy deposition,Femtosecond laser,Temporally shaped pulse,Chemical etching,Fused silica
更新于2025-09-23 15:19:57
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The effect of spot overlap ratio on femtosecond laser planarization processing of SiC ceramics
摘要： Silicon carbide ceramics are widely used in many fields owing to their excellent mechanical properties such as good wear resistance, thermal stability, and chemical corrosion resistance. The laser planarization processing can effectively achieve the functional, practical, and engineering process, satisfying the demands of the assembly precision. Therefore, different spot overlap ratios were utilized to investigate the effect of femtosecond laser planarization processing on silicon carbide ceramic samples. Various scanning speeds and laser repetition frequencies were matched to achieve different spot overlap ratios under the premise of fixed laser incident angle and single pulse energy. Under different parameters, the ablation depth, surface roughness, surface morphology, oxidation, and residual stress were compared. The result showed that at the same spot overlap ratio, the ablation depth and surface roughness are basically maintained at a stable value despite the difference in the scanning speed and repetition rate. The surface oxidation phenomenon remarkably decreased at the spot overlap ratio less than 90%. The decrease in the overlap ratio leads to the transition of the low frequency nano-ripple and the high frequency nano-ripple, and the surface residual stress converted from tensile stress to compressive stress. Combining processing requirements with ablation quality, the parameters are divided into three parts to fit three processes based on the spot overlap ratios. The variation in the spot overlap ratios as the guidelines had good potential in guiding the parameter range selection.
关键词： Residual stress,Spot overlap ratios,Femtosecond laser,Silicon carbide ceramics,Planarization processing
更新于2025-09-23 15:19:57
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Waveguides written in silver-doped tellurite glasses
摘要： We have studied the optical properties of channel waveguides written using a femtosecond laser in tellurite-zinc glasses doped with metallic silver (%TeO2%ZnO:Ag). Our findings showed that the tellurium dioxide glasses could be significantly affected by the silver presence, even with low silver concentration. By properly choosing the parameters and glassy matrix the written waveguides presented lower optical insertion losses and greater refractive index change.
关键词： Femtosecond laser writing,Silver nanoparticles,Waveguides,Tellurite glass
更新于2025-09-23 15:19:57
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Insights into Ultrashort Laser-Driven Au:TiO <sub/>2</sub> Nanocomposite Formation
摘要： Modern methods of laser-based nanocomposite fabrication and treatment rely on a deep understanding of the interplay between a set of mechanisms involved, such as nanoparticle growth and decay, material phase transformation, degradation and damage. In this work, scanning multi-pulse femtosecond laser irradiation is used for Au : T iO2 nanocomposite formation. Depending on laser scan speed two di?erent regimes are observed revealing di?erent gold nanoparticle growth rates. The regime of the remarkably fast laser-induced growth of Au nanoparticles is found to be accompanied by the cavity formation in titania ?lm around the particles. The transition between two formation regimes is found to be abrupt con?rming the catastrophic mechanism of Au nanoparticle growth. The obtained results are analyzed based on the developed numerical model including e?ects such as nanoparticle absorption, local ?eld enhancement, photo-induced free carrier generation, plasmon-assisted electron emission, and thermal heat transfer from nanoparticles towards titania matrix. Our modeling reveals the crucial role of collective thermoplasmonic e?ects caused namely by bimodal nanoparticle size distribution. The performed analysis also suggests that spall in solid state is responsible for ?nal matrix degradation if nanoparticles become large enough. The considered laser-based formation of optical nanocomposites is crucial not only for the better understanding of ultra-short laser interactions with glass-metallic nanocomposite materials, but also for numerous applications in photocatalysts, solar cells, and chemo-sensors.
关键词： femtosecond laser,nanocomposite,thermoplasmonic effects,nanoparticle growth,Au:TiO2
更新于2025-09-23 15:19:57
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Femtosecond Laser-assisted Preparation of Conjunctival Autograft for Pterygium Surgery
摘要： Femtosecond laser-assisted conjunctival autografts (CAG) preparation was recently proposed. This study reports the outcomes of the first clinical trial on the use of laser to prepare CAG in pterygium surgery, and to compare the outcomes with those of manual technique. Forty eyes undergoing primary pterygium excision with laser-assisted CAG transplantation were prospectively included (L group). Two historical matched cohorts whose cAGs were prepared manually were compared (n = 78 eyes by the same experienced surgeon, M group; n = 78 eyes by trainees; TM group). We found the laser-created CAGs had only 11 μm deviation from the targeted thickness. The best-corrected visual acuity improved, and the astigmatism significantly decreased after surgery, with comparable efficacy across 3 groups. The 1-year recurrence rate was 2.5%, 3.8% and 7.7% in the L, M and TM groups, respectively (P = 0.12). There was no significant difference between the L and M groups in the complication rate (5.0% and 1.3%, respectively), surgical time (19.4 ± 5.1 and 19.1 ± 6.2 minutes, respectively), and postoperative discomfort scores (0.1 ± 0.3 and 0.2 ± 0.3, respectively), but these outcomes were significantly less favorable in the TM group. The results of this first comparative clinical trial suggest that femtosecond laser-assisted CAG preparation can be considered as an alternative technique for CAGs preparation.
关键词： femtosecond laser,conjunctival autograft,recurrence rate,clinical trial,pterygium surgery
更新于2025-09-23 15:19:57
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Microvascular changes in macula and optic nerve head after femtosecond laser-assisted LASIK: an optical coherence tomography angiography study
摘要： To measure the microcirculation change of macula and optic nerve head before and after femtosecond laser assisted laser in situ keratomileusis. In total 45 eyes from 45 subjects, who underwent FS-LASIK during June 2017 to December 2017 in Guangdong Provincial People’s Hospital, were recruited in this study. Vessel density in macula and optic nerve head were measured by optical coherence tomography angiography before and after transient elevation in intraocular pressure caused by application of suction ring during surgery. Vessel density (VD) at superficial (SCP) plexus of macular region did not differ after surgery (F(3,132) = 1.41, P = 0.24), while the deep (DCP) plexus of macular region significantly decreased 1 day after surgery (P = 0.001) but returned to its baseline value 1 month postoperatively (P = 0.1). Vessel density of optic nerve head region had no significant changes after surgery (F(2.51,95.18) = 0.6, P = 0.59). A short-term temporary decrease of vessel density at deep layer of macular region was observed in eyes undergoing FS-LASIK. However, the retinal capillary density went back to preoperative level 1 month after surgery. Therefore, transient IOP spike during FS-LASIK did not cause long-term decline of retinal microcirculation.
关键词： Optical coherence tomography angiography,Femtosecond laser-assisted LASIK,Microvascular changes,Macula,Optic nerve head
更新于2025-09-23 15:19:57