In our previous study, metals have been used as absorbers in the clear plastic laser transmission welding. The effects of metal thermal conductivity on the welding quality are investigated in the present work. Four me...In our previous study, metals have been used as absorbers in the clear plastic laser transmission welding. The effects of metal thermal conductivity on the welding quality are investigated in the present work. Four metals with distinctly different thermal conductivities, i.e., titanium, nickel, molybdenum, and copper, are selected as light absorbers. The lap welding is conducted with an 808 nm diode laser and simulation experiments are also conducted. Nickel electroplating test is carried out to minimize the side-effects from different light absorptivities of different metals. The results show that the welding with an absorber of higher thermal conductivity can accommodate higher laser input power before smoking, which produces a wider and stronger welding seam.The positive role of the higher thermal conductivity can be attributed to the fact that a desirable thermal field distribution for the molecular diffusion and entanglement is produced from the case with a high thermal conductivity.展开更多
The design,fabrication and performance of narrow-band rugate minus filters are investigated in this paper.A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O_(2))and high(Al_(2)...The design,fabrication and performance of narrow-band rugate minus filters are investigated in this paper.A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O_(2))and high(Al_(2)O_(3))refractive index materials is presented to fabricate a rugate structure.The narrow-band rugate minus filter design and fabrication approaches are discussed in detail.The experimental results,including transmittance spectrum,surface damage test and damage morphology investigated with a scanning electron microscope,demonstrate the high performance of the as-fabricated spatial filter and confirm the feasibility of the fabrication method for narrow-band rugate minus filters.展开更多
We report on the fabrication of the lO-mm-long lithium niobate ridge waveguide and its supercontinuum gen- eration at near-visible wavelengths (around 800hm). The waveguides are fabricated by a combination of MeV co...We report on the fabrication of the lO-mm-long lithium niobate ridge waveguide and its supercontinuum gen- eration at near-visible wavelengths (around 800hm). The waveguides are fabricated by a combination of MeV copper ion implantation followed by wet etching in a proton exchanged lithium niobate planar waveguide. Using a mode-locked Ti:sapphire laser with a central wavelength of 800nm, the generated broadest supereontinuum through the ridge waveguides spans 302 nm (at -30 dB points), from 693 to 995 nm. Temporal coherence proper- ties of the supercontinuum are experimentally studied by a Michelson interferometer and the coherence length of the broadest supercontinuum is measured to be 5.2 μm. Our results offer potential for a compact and integrated supercontinuum source for applications including bio-imaging, spectroscopy and optical communication.展开更多
基金Supported by the National Key R&D Program of China under Grant No 2016YFA0401100the National Natural Science Foundation of China under Grant No 61575129the National High-Technology Research and Development Program of China under Grant No 2015AA021102
文摘In our previous study, metals have been used as absorbers in the clear plastic laser transmission welding. The effects of metal thermal conductivity on the welding quality are investigated in the present work. Four metals with distinctly different thermal conductivities, i.e., titanium, nickel, molybdenum, and copper, are selected as light absorbers. The lap welding is conducted with an 808 nm diode laser and simulation experiments are also conducted. Nickel electroplating test is carried out to minimize the side-effects from different light absorptivities of different metals. The results show that the welding with an absorber of higher thermal conductivity can accommodate higher laser input power before smoking, which produces a wider and stronger welding seam.The positive role of the higher thermal conductivity can be attributed to the fact that a desirable thermal field distribution for the molecular diffusion and entanglement is produced from the case with a high thermal conductivity.
基金Project supported by the Postdoctoral Science Foundation of China(Grant Nos.2016M592528 and 2016M602517)the Natural Science Foundation of Guangdong Province,China(Grant No.2017A030310130)the National Natural Science Foundation of China(Grant No.11705259)
文摘The design,fabrication and performance of narrow-band rugate minus filters are investigated in this paper.A method of fabricating graded-index coatings by rapidly alternating deposition of low(Si O_(2))and high(Al_(2)O_(3))refractive index materials is presented to fabricate a rugate structure.The narrow-band rugate minus filter design and fabrication approaches are discussed in detail.The experimental results,including transmittance spectrum,surface damage test and damage morphology investigated with a scanning electron microscope,demonstrate the high performance of the as-fabricated spatial filter and confirm the feasibility of the fabrication method for narrow-band rugate minus filters.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61575129 and 11375105the Postdoctoral Science Foundation of China under Grant No 2016M602511+1 种基金the Shenzhen Science and Technology Planning under Grant No JCYJ20160422142912923the State Key Laboratory of Nuclear Physics and Technology,Peking University
文摘We report on the fabrication of the lO-mm-long lithium niobate ridge waveguide and its supercontinuum gen- eration at near-visible wavelengths (around 800hm). The waveguides are fabricated by a combination of MeV copper ion implantation followed by wet etching in a proton exchanged lithium niobate planar waveguide. Using a mode-locked Ti:sapphire laser with a central wavelength of 800nm, the generated broadest supereontinuum through the ridge waveguides spans 302 nm (at -30 dB points), from 693 to 995 nm. Temporal coherence proper- ties of the supercontinuum are experimentally studied by a Michelson interferometer and the coherence length of the broadest supercontinuum is measured to be 5.2 μm. Our results offer potential for a compact and integrated supercontinuum source for applications including bio-imaging, spectroscopy and optical communication.