A detailed procedure for the calculation of the third-harmonic-generation susceptibility tensor is given in special asymmetric quantum wells, and an analytic formula for the third-harmonic-generation susceptibility is...A detailed procedure for the calculation of the third-harmonic-generation susceptibility tensor is given in special asymmetric quantum wells, and an analytic formula for the third-harmonic-generation susceptibility is obtained by the compact density matrix approach and the iterative procedure. Finally, the numerical results are presented for typical GaAs/AlGaAs asymmetric quantum wells. The calculated results show that the origin of the large thirdharmonic-generation susceptibility is due to the increase in asymmetry of the quantum well.展开更多
We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms lim...We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms limits the high signal-to-noise ratio of atomic laser spectroscopy, which can be usually realized by optical-optical double-resonance or double-resonance optical pumping for cascade-type energy structure atoms. For ^87Rb atoms, the weak 420 nm transition spectrum between the energy level of 5^2S1/2 and 6^2P3/2 is transferred to the spectrum on lower excited states at 780nm with strong oscillator strength, which is recorded by a 780 nm probe laser. This method, which ＆ similar to the electron-shelving detection method, at a certain degree can indirectly measure a higher excited state transition with weak oscillator strength for any V-type energy structure of atoms by transferring the transition spectrum information of the very weak oscillator strength to the strong oscillator strength in an optical-optical double-resonance configuration.展开更多
A transmission filter composed of a Sagnac loop and a fiber Bragg grating is studied in detail. It is found that the transmission spectrum of this filter is the splitting of the reflection spectrum of the fiber Bragg ...A transmission filter composed of a Sagnac loop and a fiber Bragg grating is studied in detail. It is found that the transmission spectrum of this filter is the splitting of the reflection spectrum of the fiber Bragg gratings. The filter can behave as a multiple-passband filter when the fiber Bragg grating is strong and as a single-band filter when the fiber Bragg grating is weak. Very narrow transmission filters can be Obtained in this way.展开更多
Supercontinuum spectrum generation in a dispersion-flattened and decreasing fiber with two orthogonally polarized pulses was simulated and calculated. The research results indicated that the supercontinuum spectrum ge...Supercontinuum spectrum generation in a dispersion-flattened and decreasing fiber with two orthogonally polarized pulses was simulated and calculated. The research results indicated that the supercontinuum spectrum generated by two orthogonally polarized pulses is wider and flatter than that generated by single polarized pulse due to cross-phase modulation. The cross-phase modulation effect can enhance the supercontinuum spectrum generation. When the pump power of the input pulse is lower, the enhancement of supercontinuum spectrum generation by cross-phase modulation effect is more significant.展开更多
文摘A detailed procedure for the calculation of the third-harmonic-generation susceptibility tensor is given in special asymmetric quantum wells, and an analytic formula for the third-harmonic-generation susceptibility is obtained by the compact density matrix approach and the iterative procedure. Finally, the numerical results are presented for typical GaAs/AlGaAs asymmetric quantum wells. The calculated results show that the origin of the large thirdharmonic-generation susceptibility is due to the increase in asymmetry of the quantum well.
文摘We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms limits the high signal-to-noise ratio of atomic laser spectroscopy, which can be usually realized by optical-optical double-resonance or double-resonance optical pumping for cascade-type energy structure atoms. For ^87Rb atoms, the weak 420 nm transition spectrum between the energy level of 5^2S1/2 and 6^2P3/2 is transferred to the spectrum on lower excited states at 780nm with strong oscillator strength, which is recorded by a 780 nm probe laser. This method, which ＆ similar to the electron-shelving detection method, at a certain degree can indirectly measure a higher excited state transition with weak oscillator strength for any V-type energy structure of atoms by transferring the transition spectrum information of the very weak oscillator strength to the strong oscillator strength in an optical-optical double-resonance configuration.
文摘A transmission filter composed of a Sagnac loop and a fiber Bragg grating is studied in detail. It is found that the transmission spectrum of this filter is the splitting of the reflection spectrum of the fiber Bragg gratings. The filter can behave as a multiple-passband filter when the fiber Bragg grating is strong and as a single-band filter when the fiber Bragg grating is weak. Very narrow transmission filters can be Obtained in this way.
基金Excellent Teacher Foundation of Guangdong Province(Q02084) Natural Science Foundation of Guangdong Province(04010397)
文摘Supercontinuum spectrum generation in a dispersion-flattened and decreasing fiber with two orthogonally polarized pulses was simulated and calculated. The research results indicated that the supercontinuum spectrum generated by two orthogonally polarized pulses is wider and flatter than that generated by single polarized pulse due to cross-phase modulation. The cross-phase modulation effect can enhance the supercontinuum spectrum generation. When the pump power of the input pulse is lower, the enhancement of supercontinuum spectrum generation by cross-phase modulation effect is more significant.
