A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3＋-doped yttrium aluminium garnet （YAG） crystal, which is achieved for a probe field between the excited sta...A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3＋-doped yttrium aluminium garnet （YAG） crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3＋ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.展开更多
We have investigated the optical properties of gallium arsenide(GaAs) in the photon energy range 0.6- 6.0 eV.We obtained a refractive index which has a maximum value of 5.0 at a photon energy of 3.1 eV;an extinction c...We have investigated the optical properties of gallium arsenide(GaAs) in the photon energy range 0.6- 6.0 eV.We obtained a refractive index which has a maximum value of 5.0 at a photon energy of 3.1 eV;an extinction coefficient which has a maximum value of 4.2 at a photon energy of 5.0 eV;the dielectric constant,the real part of the complex dielectric constant has a maximum value of 24 at a photon energy of 2.8 eV and the imaginary part of the complex dielectric constant has a maximum value of 26.0 at a photon energy of 4.8 eV;the transmittance which has a maximum value of 0.22 at a photon energy of 4.0 eV;the absorption coefficient which has a maximum value of 0.22×10~8 m^(-1) at a photon energy of 4.8 eV,the reflectance which has a maximum value of 0.68 at 5.2eV; the reflection coefficient which has a maximum value of 0.82 at a photon energy of 5.2 eV;the real part of optical conductivity has a maximum value of 14.2×10^(15) at 4.8 eV and the imaginary part of the optical conductivity has a maximum value of 6.8×10^(15) at 5.0 eV.The values obtained for the optical properties of GaAs are in good agreement with other results.展开更多
We show that dielectric waveguides formed by materials with strong optical anisotropy support electromagnetic waves that combine the properties of propagating and evanescent fields.These“ghost waves”are created in t...We show that dielectric waveguides formed by materials with strong optical anisotropy support electromagnetic waves that combine the properties of propagating and evanescent fields.These“ghost waves”are created in tangent bifurcations that“annihilate”pairs of positive-and negative-index modes and represent the optical analogue of the“ghost orbits”in the quantum theory of nonintegrable dynamical systems.Ghost waves can be resonantly coupled to the incident evanescent field,which then grows exponentially through the anisotropic media—as in the case of negative index materials.As ghost waves are supported by transparent dielectric media,the proposed approach to electromagnetic field enhancement is free from the“curse”of material loss that is inherent to conventional negative index composites.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant No 10334010）.
文摘A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3＋-doped yttrium aluminium garnet （YAG） crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3＋ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.
文摘We have investigated the optical properties of gallium arsenide(GaAs) in the photon energy range 0.6- 6.0 eV.We obtained a refractive index which has a maximum value of 5.0 at a photon energy of 3.1 eV;an extinction coefficient which has a maximum value of 4.2 at a photon energy of 5.0 eV;the dielectric constant,the real part of the complex dielectric constant has a maximum value of 24 at a photon energy of 2.8 eV and the imaginary part of the complex dielectric constant has a maximum value of 26.0 at a photon energy of 4.8 eV;the transmittance which has a maximum value of 0.22 at a photon energy of 4.0 eV;the absorption coefficient which has a maximum value of 0.22×10~8 m^(-1) at a photon energy of 4.8 eV,the reflectance which has a maximum value of 0.68 at 5.2eV; the reflection coefficient which has a maximum value of 0.82 at a photon energy of 5.2 eV;the real part of optical conductivity has a maximum value of 14.2×10^(15) at 4.8 eV and the imaginary part of the optical conductivity has a maximum value of 6.8×10^(15) at 5.0 eV.The values obtained for the optical properties of GaAs are in good agreement with other results.
基金This work was partially supported by the National Science Foundation(Grant No.DMREF-1629276)Army Research Office(Grant No.W911NF-14-1-0639),and Gordon and Betty Moore Foundation.
文摘We show that dielectric waveguides formed by materials with strong optical anisotropy support electromagnetic waves that combine the properties of propagating and evanescent fields.These“ghost waves”are created in tangent bifurcations that“annihilate”pairs of positive-and negative-index modes and represent the optical analogue of the“ghost orbits”in the quantum theory of nonintegrable dynamical systems.Ghost waves can be resonantly coupled to the incident evanescent field,which then grows exponentially through the anisotropic media—as in the case of negative index materials.As ghost waves are supported by transparent dielectric media,the proposed approach to electromagnetic field enhancement is free from the“curse”of material loss that is inherent to conventional negative index composites.
