Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining p...Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining properties for laser assisted milling（LAML）, few attempts have been made to extend LAML to machining parts with complex geometric features. A methodology for continuous path machining for LAML is developed by integration of a rotary and movable table into an ordinary milling machine with a laser beam system. The machining strategy and processing path are investigated to determine alignment of the machining path with the laser spot. In order to keep the material removal temperatures above the softening temperature of silicon nitride, the transformation is coordinated and the temperature interpolated, establishing a transient thermal model. The temperatures of the laser center and cutting zone are also carefully controlled to achieve optimal machining results and avoid thermal damage. These experiments indicate that the system results in no surface damage as well as good surface roughness, validating the application of this machining strategy and thermal model in the development of a new LAML system for continuous path processing of silicon nitride. The proposed approach can be easily applied in LAML system to achieve continuous processing and improve efficiency in laser assisted machining.展开更多
As a novel solution-processable laser material with excellent optical properties,high biocompatibility,and low toxicity,the intrinsic value of carbon dots and their role in optimizing small-scale lasers as a gain medi...As a novel solution-processable laser material with excellent optical properties,high biocompatibility,and low toxicity,the intrinsic value of carbon dots and their role in optimizing small-scale lasers as a gain medium have received extensive attention.In this review,we systematically summarize a series of properties of carbon dots themselves and the carbon dot(CD)lasers fabricated based on them.Specifically,we first summarize the photoluminescence principle of carbon dots as well as their synthesis and modification methods.Secondly,we organize the current types of CD lasers.Finally,we summarize the applications of carbon dots and CD lasers,the current challenges they face,and provide outlooks and speculations for their future.It is hoped that this review can help other researchers comprehensively and completely understand or review the overall picture of carbon dots and CD lasers in the shortest possible time.展开更多
Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to p...Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.展开更多
Femtosecond laser is a perfect laser source for materials processing when high accuracy and small structure size are required. Due to the ultra short interaction time and the high peak power, the process is generally ...Femtosecond laser is a perfect laser source for materials processing when high accuracy and small structure size are required. Due to the ultra short interaction time and the high peak power, the process is generally characterized by the absence of heat diffusion and, consequently molten layers. Various induced structures have been observed in materials after the femtosecond laser irradiation. Here, we report on fabrication of micro-optical devices by the femtosecond laser. 1) formation of optical waveg...展开更多
Laser technology has evolved significantly over the last 30 years,and laser devices have become integral tools for skin rejuvenation in the hands of many plastic surgeons practicing today.The purpose of this article i...Laser technology has evolved significantly over the last 30 years,and laser devices have become integral tools for skin rejuvenation in the hands of many plastic surgeons practicing today.The purpose of this article is to briefly review the history of aesthetic laser technology,to discuss patient selection and expectations for various laser devices,and finally to review the technology and applications of these devices.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.51205097)China Postdoctoral Science Foundation(Grant No.2013M541401)
文摘Laser assisted machining is an effective method to machine advanced materials with the added benefits of longer tool life and increased material removal rates. While extensive studies have investigated the machining properties for laser assisted milling（LAML）, few attempts have been made to extend LAML to machining parts with complex geometric features. A methodology for continuous path machining for LAML is developed by integration of a rotary and movable table into an ordinary milling machine with a laser beam system. The machining strategy and processing path are investigated to determine alignment of the machining path with the laser spot. In order to keep the material removal temperatures above the softening temperature of silicon nitride, the transformation is coordinated and the temperature interpolated, establishing a transient thermal model. The temperatures of the laser center and cutting zone are also carefully controlled to achieve optimal machining results and avoid thermal damage. These experiments indicate that the system results in no surface damage as well as good surface roughness, validating the application of this machining strategy and thermal model in the development of a new LAML system for continuous path processing of silicon nitride. The proposed approach can be easily applied in LAML system to achieve continuous processing and improve efficiency in laser assisted machining.
基金supported by the National Natural Science Foundation of China(No.12261141661)the Natural Science Foundation of Henan Province(No.242300421179)。
文摘As a novel solution-processable laser material with excellent optical properties,high biocompatibility,and low toxicity,the intrinsic value of carbon dots and their role in optimizing small-scale lasers as a gain medium have received extensive attention.In this review,we systematically summarize a series of properties of carbon dots themselves and the carbon dot(CD)lasers fabricated based on them.Specifically,we first summarize the photoluminescence principle of carbon dots as well as their synthesis and modification methods.Secondly,we organize the current types of CD lasers.Finally,we summarize the applications of carbon dots and CD lasers,the current challenges they face,and provide outlooks and speculations for their future.It is hoped that this review can help other researchers comprehensively and completely understand or review the overall picture of carbon dots and CD lasers in the shortest possible time.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 11474108, 61378036, 61307058, 11304101, 11074078)the PhD Start-up Fund of Natural Science Foundation of Guangdong Province, China (Grant No. S2013040016320)+2 种基金the Scientific and Technological Innovation Project of Higher Education Institute, Guangdong, China (Grant No. 2013KJCX0051)the financial support from the Guangdong Natural Science Funds for Distinguished Young Scholarthe Zhujiang New-star Plan of Science & Technology in Guangzhou City (Grant No. 2014J2200008)
文摘Two-dimensional（2D） materials have emerged as attractive mediums for fabricating versatile optoelectronic devices. Recently, few-layer molybdenum disulfide（MoS2）, as a shining 2D material, has been discovered to possess both the saturable absorption effect and large nonlinear refractive index. Herein, taking advantage of the unique nonlinear optical properties of MoS2, we fabricated a highly nonlinear saturable absorption photonic device by depositing the few-layer MoS2 onto the microfiber. With the proposed MoS2 photonic device, apart from the conventional soliton patterns, the mode-locked pulses could be shaped into some new soliton patterns, namely,multiple soliton molecules, localized chaotic multipulses, and double-scale soliton clusters. Our findings indicate that the few-layer MoS2-deposited microfiber could operate as a promising highlynonlinear photonic device for the related nonlinear optics applications.
文摘Femtosecond laser is a perfect laser source for materials processing when high accuracy and small structure size are required. Due to the ultra short interaction time and the high peak power, the process is generally characterized by the absence of heat diffusion and, consequently molten layers. Various induced structures have been observed in materials after the femtosecond laser irradiation. Here, we report on fabrication of micro-optical devices by the femtosecond laser. 1) formation of optical waveg...
文摘Laser technology has evolved significantly over the last 30 years,and laser devices have become integral tools for skin rejuvenation in the hands of many plastic surgeons practicing today.The purpose of this article is to briefly review the history of aesthetic laser technology,to discuss patient selection and expectations for various laser devices,and finally to review the technology and applications of these devices.
