The knowledge of the hyperpolarizabilities of atoms and ions is helpful for the analysis of the high order effects of the frequency shifts in precision spectroscopy experiments. Liu et al. [Phys. Rev. Lett. 114, 2230...The knowledge of the hyperpolarizabilities of atoms and ions is helpful for the analysis of the high order effects of the frequency shifts in precision spectroscopy experiments. Liu et al. [Phys. Rev. Lett. 114, 223001 （2015）] proposed to establish all-optical trapped ion clocks using laser at the magic wavelength for clock transition. To evaluate the high-order frequency shifts in this new scheme of optical clocks, hyperpolarizabilities are needed, but absent. Using the finite field method based on the B-spline basis set and model potentials, we calculated the electric-field-dependent energy shifts of the ground and low-lying excited states in Be＋, Mg＋, and Ca＋ in the field strength range of 0.0-6×10-5 a.u.. The scalar and tensor polarizabilities （α0, α2） and hyperpolarizabilities （Y0,Y2, 74） were deduced. The results of the hyperpolarizabilities for Be＋ showed good agreement with the values in literature, implying that the present method can be applied for the effective estimation of the atomic hyperpolarizabilities, which are rarely reported but needed in experiments. The feasibility of optical trapping of Ca＋ is discussed, and the contributions of hyperpolarizabilities to the transition frequency shift for Ca＋ in the optical dipole trap are estimated using quasi-electrostatic approximation.展开更多
A novel polarization splitter based on photonic crystal fibers(PCFs) with three cores of high birefringence is proposed.The 45o linearly polarized light is launched into a core.After a coupling length(about 1500 μm),...A novel polarization splitter based on photonic crystal fibers(PCFs) with three cores of high birefringence is proposed.The 45o linearly polarized light is launched into a core.After a coupling length(about 1500 μm),the xand y-polarized light beams are separated into different cores.When the light is launched into another core,the xand y-polarized light from different cores can be obtained and the degree of separation can be also adjusted.The polarization splitter is highly flexible and adjustable.The length of the polarization splitter is about 1500 μm which is just the coupling length.So it has appreciate significance of manufacturing mini-type photonic apparatus in integrated optics.展开更多
We describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier （GT-SOA） which brings in the assistant li...We describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier （GT-SOA） which brings in the assistant light to improve the property of the converted light. From the SOA carder density equations, the 1310 nm-to-1550 nm wavelength conversion scheme is analyzed by the Jones matrix. The phase shift between TE and TM modes and the converted light are simulated at bit rate of 30 Gbit/s. We also analyze the influence of the input signal power, the injected current and the assistant light power on the extinction ratio of the converted li~,ht.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 91536102)the National Basic Research Program of China (Grant No. 2012CB821305)
文摘The knowledge of the hyperpolarizabilities of atoms and ions is helpful for the analysis of the high order effects of the frequency shifts in precision spectroscopy experiments. Liu et al. [Phys. Rev. Lett. 114, 223001 （2015）] proposed to establish all-optical trapped ion clocks using laser at the magic wavelength for clock transition. To evaluate the high-order frequency shifts in this new scheme of optical clocks, hyperpolarizabilities are needed, but absent. Using the finite field method based on the B-spline basis set and model potentials, we calculated the electric-field-dependent energy shifts of the ground and low-lying excited states in Be＋, Mg＋, and Ca＋ in the field strength range of 0.0-6×10-5 a.u.. The scalar and tensor polarizabilities （α0, α2） and hyperpolarizabilities （Y0,Y2, 74） were deduced. The results of the hyperpolarizabilities for Be＋ showed good agreement with the values in literature, implying that the present method can be applied for the effective estimation of the atomic hyperpolarizabilities, which are rarely reported but needed in experiments. The feasibility of optical trapping of Ca＋ is discussed, and the contributions of hyperpolarizabilities to the transition frequency shift for Ca＋ in the optical dipole trap are estimated using quasi-electrostatic approximation.
基金supported by the National Natural Science Foundation of China (No. 60637010)
文摘A novel polarization splitter based on photonic crystal fibers(PCFs) with three cores of high birefringence is proposed.The 45o linearly polarized light is launched into a core.After a coupling length(about 1500 μm),the xand y-polarized light beams are separated into different cores.When the light is launched into another core,the xand y-polarized light from different cores can be obtained and the degree of separation can be also adjusted.The polarization splitter is highly flexible and adjustable.The length of the polarization splitter is about 1500 μm which is just the coupling length.So it has appreciate significance of manufacturing mini-type photonic apparatus in integrated optics.
基金supported by the National Natural Science Foundation of China(No.61077014)
文摘We describe an all-optical wavelength conversion scheme for 1310 nm to 1550 nm based on nonlinear polarization rotation in a gain-transparent semiconductor optical amplifier （GT-SOA） which brings in the assistant light to improve the property of the converted light. From the SOA carder density equations, the 1310 nm-to-1550 nm wavelength conversion scheme is analyzed by the Jones matrix. The phase shift between TE and TM modes and the converted light are simulated at bit rate of 30 Gbit/s. We also analyze the influence of the input signal power, the injected current and the assistant light power on the extinction ratio of the converted li~,ht.
