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
A 52 m/9 Gb/s four-level pulse amplitude modulation（PAM4） plastic optical fiber（POF）-underwater wireless laser transmission（UWLT） convergence with a laser beam reducer is proposed. A 52 m/9 Gb/s PAM4 POFUWLT con...A 52 m/9 Gb/s four-level pulse amplitude modulation（PAM4） plastic optical fiber（POF）-underwater wireless laser transmission（UWLT） convergence with a laser beam reducer is proposed. A 52 m/9 Gb/s PAM4 POFUWLT convergence is practically demonstrated with the application of a laser beam reducer to reduce the collimated beam diameter. A 50 m graded-index（GI）-POF is employed as an underwater extender to efficiently enhance the coverage of UWLT. The performances of PAM4 POF-UWLT convergence in view of bit error rate（BER） and eye diagrams improve with the decrease of the collimated beam diameter because of the small amount of light absorbed by clear ocean water. Competent BER and eye diagrams（three independent eye diagrams） are achieved over a 50 m GI-POF transmission with a 2 m clear ocean water link.展开更多
The physical properties of light fields at the subwavelength scale have emerged as extensively pursued objectives in nano-optics,photonics,and plasmonics.Here,we report that in the paraxial regime,the spectral density...The physical properties of light fields at the subwavelength scale have emerged as extensively pursued objectives in nano-optics,photonics,and plasmonics.Here,we report that in the paraxial regime,the spectral density and the spectral axial coherence(z-coherence)structures in a submicron range can be generated by employing a light beam with a suitably chosen spatial coherence state in a counter-propagating configuration,in an open-end cavity.It is established that while the spectral density forms an optical standing wave,the z-coherence state depends on the symmetry of the selected point pair and in particular,the phenomenon termed as periodical coherence switch is found.Our findings shed new light on the discussion of the role of spatial coherence in the photonic cavities,possibly inspiring further studies in the field of enhanced light-nanomaterials interactions by optical cavity.This provides a versatile framework for tailoring coherence in subwavelength space with promising applications in metrology and imaging.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the financial support from the Ministry of Science and Technology of Taiwan, China (Nos. MOST 104-2221-E-027-072-MY3 and MOST 106-2221-E-027-073)
文摘A 52 m/9 Gb/s four-level pulse amplitude modulation（PAM4） plastic optical fiber（POF）-underwater wireless laser transmission（UWLT） convergence with a laser beam reducer is proposed. A 52 m/9 Gb/s PAM4 POFUWLT convergence is practically demonstrated with the application of a laser beam reducer to reduce the collimated beam diameter. A 50 m graded-index（GI）-POF is employed as an underwater extender to efficiently enhance the coverage of UWLT. The performances of PAM4 POF-UWLT convergence in view of bit error rate（BER） and eye diagrams improve with the decrease of the collimated beam diameter because of the small amount of light absorbed by clear ocean water. Competent BER and eye diagrams（three independent eye diagrams） are achieved over a 50 m GI-POF transmission with a 2 m clear ocean water link.
基金supported by the National Natural Science Foundation of China(Grant Nos.11874321,and 12174338)the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province(Grant No.20204BCJ22012)the UM for Copper Fellowship support。
文摘The physical properties of light fields at the subwavelength scale have emerged as extensively pursued objectives in nano-optics,photonics,and plasmonics.Here,we report that in the paraxial regime,the spectral density and the spectral axial coherence(z-coherence)structures in a submicron range can be generated by employing a light beam with a suitably chosen spatial coherence state in a counter-propagating configuration,in an open-end cavity.It is established that while the spectral density forms an optical standing wave,the z-coherence state depends on the symmetry of the selected point pair and in particular,the phenomenon termed as periodical coherence switch is found.Our findings shed new light on the discussion of the role of spatial coherence in the photonic cavities,possibly inspiring further studies in the field of enhanced light-nanomaterials interactions by optical cavity.This provides a versatile framework for tailoring coherence in subwavelength space with promising applications in metrology and imaging.
