Electron impact excitation of tetrasulfur S4 molecule is investigated in this work using R-matrix method. The twelve low-lying electronic states are used in close-coupling expansion to represent the target states, and...Electron impact excitation of tetrasulfur S4 molecule is investigated in this work using R-matrix method. The twelve low-lying electronic states are used in close-coupling expansion to represent the target states, and the integral cross sections for elastic scattering and excitation into the six lowest electronic states are calculated.展开更多
The operation of an ultra-narrow bandwidth optical filter based on the 5P3/2→5D3/2 excited-state transition in rubidium vapor is reported. The 5D3/2 state is excited by a circularly polarized pump beam at 780 nm from...The operation of an ultra-narrow bandwidth optical filter based on the 5P3/2→5D3/2 excited-state transition in rubidium vapor is reported. The 5D3/2 state is excited by a circularly polarized pump beam at 780 nm from a diode laser. The filter displays a single 398-MHz bandwidth at a peak transmission of 9.0%, which is narrower than the Doppler bandwidth. The dependence of peak transmission on the pump intensity and cell temperature is also given.展开更多
Two LICET transitions in Cs-Sr systems are suggested and the results of numerical calculations of the transition probability and collisional crosssection are obtained respectively from our four-level model and the con...Two LICET transitions in Cs-Sr systems are suggested and the results of numerical calculations of the transition probability and collisional crosssection are obtained respectively from our four-level model and the conventional three-level model. Comparisons of these results prove the theoretical prediction that if the frequency difference ω21, is comparable to ω43, the three-level theory has great error in describing the LICET transition, while the four-level theory can describe all cases of LICET process perfectly.展开更多
Theoretically based on the four-level model,one LICET process in Eu-Sr system in both weak and strong fields was calculated by immediate numerical integrations.Numerical results in weak field are in fair to good agree...Theoretically based on the four-level model,one LICET process in Eu-Sr system in both weak and strong fields was calculated by immediate numerical integrations.Numerical results in weak field are in fair to good agreement with analytical ones.Numerical results in strong field show that:(a)the peak of the LICET profiles moves to the violet side and the tuning range of the profiles obviously becomes narrower when the laser field intensity increases;and(b)numerical results in strong field differ a lot from analytical ones,which indicates that in strong field,the analytical expressions are not applicable any longer.展开更多
The optical limiting behaviors of nano-gold self-assembled multi-wall carbon nanotube (MWNT) were experimentally investigated at 532 and 1064 nm, respectively. The comparison of the limiting performances between carbo...The optical limiting behaviors of nano-gold self-assembled multi-wall carbon nanotube (MWNT) were experimentally investigated at 532 and 1064 nm, respectively. The comparison of the limiting performances between carbon nanotube suspension, C60 solution, and carbon black suspension (CBS) was performed. The results show that the optical limiting characteristic of nano-gold self-assembled MWNT is better than those of C60 and CBS. The mechanisms of the optical limiting for the samples were discussed.展开更多
Magnetic dipole（MD） transitions are important for a range of technologies from quantum light sources and displays to lasers and bio-probes. However, the typical MD transitions are much weaker than their electric cou...Magnetic dipole（MD） transitions are important for a range of technologies from quantum light sources and displays to lasers and bio-probes. However, the typical MD transitions are much weaker than their electric counterparts and are usually neglected in practical applications. Herein, we experimentally demonstrate that the MD transitions can be significantly enhanced by the well-developed magnetic metamaterials in the visible optical range. The magnetic metamaterials consist of silver nanostrips and a thick silver film, which are separated with an Eu3＋：polymethyl methacrylate（PMMA） film. By controlling the thickness of the Eu3＋：PMMA film, the magnetic resonance has been tuned to match the emission wavelength of MDs. Consequently,the intensity of MD emission has been significantly increased by around 30 times at the magnetic resonance wavelength, whereas the intensity of electric dipole emission is well-preserved. The corresponding numerical calculations reveal that the enhancement is directly generated by the magnetic resonance, which strongly increases the magnetic local density of states around the MD emitter and can efficiently radiate the MD emission into the far field. This is the first demonstration, to the best of our knowledge, that MD transitions can be improved by an additional degree of magnetic freedom, and we believe this research shall pave a new route towards bright magnetic emitters and their potential applications.展开更多
基金Project supported by the National Natural Science Foundation of China（Grant Nos 10604022 and 60278009） and the Foundation of State Key Laboratory of Tunable Laser Technology, Harbin Institute of Technology, China.
文摘Electron impact excitation of tetrasulfur S4 molecule is investigated in this work using R-matrix method. The twelve low-lying electronic states are used in close-coupling expansion to represent the target states, and the integral cross sections for elastic scattering and excitation into the six lowest electronic states are calculated.
基金This work was supported by the National Natural Science Foundation of China (No. 60272075 and 60478014) partially supported by the Program of Excellent Team in Harbin Institute of Technology (HIT).
文摘The operation of an ultra-narrow bandwidth optical filter based on the 5P3/2→5D3/2 excited-state transition in rubidium vapor is reported. The 5D3/2 state is excited by a circularly polarized pump beam at 780 nm from a diode laser. The filter displays a single 398-MHz bandwidth at a peak transmission of 9.0%, which is narrower than the Doppler bandwidth. The dependence of peak transmission on the pump intensity and cell temperature is also given.
文摘Two LICET transitions in Cs-Sr systems are suggested and the results of numerical calculations of the transition probability and collisional crosssection are obtained respectively from our four-level model and the conventional three-level model. Comparisons of these results prove the theoretical prediction that if the frequency difference ω21, is comparable to ω43, the three-level theory has great error in describing the LICET transition, while the four-level theory can describe all cases of LICET process perfectly.
文摘Theoretically based on the four-level model,one LICET process in Eu-Sr system in both weak and strong fields was calculated by immediate numerical integrations.Numerical results in weak field are in fair to good agreement with analytical ones.Numerical results in strong field show that:(a)the peak of the LICET profiles moves to the violet side and the tuning range of the profiles obviously becomes narrower when the laser field intensity increases;and(b)numerical results in strong field differ a lot from analytical ones,which indicates that in strong field,the analytical expressions are not applicable any longer.
基金The experiment was performed in Harbin Institute of Technology, State Key Laboratory of Tunable Laser Technology. This work was partially supported by the multidiscipline fund of Harbin Institute of Technology (HIT.MD.2002.01) and the fund of National Key Labo-ratory of Tunable Laser Technology. This work was also supported by the National Natural Science Foundation of China (No. 90206037), and the Research Foundation for the Doctoral Program of the Ministry of Education, P. R. China (No. 20020284022).
文摘The optical limiting behaviors of nano-gold self-assembled multi-wall carbon nanotube (MWNT) were experimentally investigated at 532 and 1064 nm, respectively. The comparison of the limiting performances between carbon nanotube suspension, C60 solution, and carbon black suspension (CBS) was performed. The results show that the optical limiting characteristic of nano-gold self-assembled MWNT is better than those of C60 and CBS. The mechanisms of the optical limiting for the samples were discussed.
基金the National Natural Science Foundation of China (No. 11374078)the Shenzhen Fundamental Research Projects (Nos. JCYJ20160301154309393, JCYJ20160505175637639, and JCYJ2016042718325 9083)+1 种基金the Public Platform for Fabrication and Detection of Micro- & Nano-Sized Aerospace Devicesthe Shenzhen Engineering Laboratory on Onganic-Inorganic Perovskite Devices for financial support
文摘Magnetic dipole（MD） transitions are important for a range of technologies from quantum light sources and displays to lasers and bio-probes. However, the typical MD transitions are much weaker than their electric counterparts and are usually neglected in practical applications. Herein, we experimentally demonstrate that the MD transitions can be significantly enhanced by the well-developed magnetic metamaterials in the visible optical range. The magnetic metamaterials consist of silver nanostrips and a thick silver film, which are separated with an Eu3＋：polymethyl methacrylate（PMMA） film. By controlling the thickness of the Eu3＋：PMMA film, the magnetic resonance has been tuned to match the emission wavelength of MDs. Consequently,the intensity of MD emission has been significantly increased by around 30 times at the magnetic resonance wavelength, whereas the intensity of electric dipole emission is well-preserved. The corresponding numerical calculations reveal that the enhancement is directly generated by the magnetic resonance, which strongly increases the magnetic local density of states around the MD emitter and can efficiently radiate the MD emission into the far field. This is the first demonstration, to the best of our knowledge, that MD transitions can be improved by an additional degree of magnetic freedom, and we believe this research shall pave a new route towards bright magnetic emitters and their potential applications.
