Liu Song-Hao

A super-broadened stimulated scattering in liquid-filled waveguide with long gain length

Using an intense visible laser pulse to excite the liquid-filled waveguide with a long gain length, we have observed a new stimulated-scattering with super-broadened spectral width (500cm-1) in addition to the sharp lines of SRS of the benzene or carbon-disulfide which is used as a filling liquid.

Effects of the microstructure slab with pillars on light extraction of GaN light-emitting diode

The positive z direction relative light extraction efficiency of GaN light-emitting diodes with microstructure slab is calculated by three-dimensional finite-difference time-domain method, where the microstructure slab consists of a graphite lattice of pillars. The results show that the two-dimensional graphite-arranged pillars suppress light extraction. When there is a thick pillar in the middle of the pillars, the structure can enhance light extraction of the light-emitting diodes. The tower-like pillars, which are thin on the top of the pillars and thick on the bottom of the pillars, benefit the light extraction when the angle of the tower-like pillars is proper.

Modulation instability of femtosecond pulses in fibres with slowly decreasing dispersion

In this paper, we investigate the modulation instability for generating femtosecond pulses in fibres with slowly decreasing dispersion. Higher-order dispersion and higher-order nonlinear effects are taken into account when the continuous wave or quasi-continuous wave evolves into sub-picosecond and femtosecond pulses by modulation instability in the optical fibres. Our research results show that the gain spectrum of the dispersion-decreasing fibres is much wider than that in conventional fibres. The third-order dispersion effect has no contribution to gain spectrum, while the self-steepening effect reduces the maximum value and gain bandwidth and the Raman self-scattering effect widens the extent to which the modulation instability occurs.

Time-resolved Fluorescence Decay Study of Hematoporphyrin Derivative

Time-resolved fluorescence decays were first performed on hematoporphyrin derivative laser No. 3 in buffer at different micelles concentration. The fluorescence lifetime constants, measured with a time-correlated single photon counting system, could be fitted by two or three exponential components with different relative peak amplitudes depending on the observation wavelength, thus indicating the presence of different emitting molecular species and/or of molecular species in different aggregational states.

Soliton Compression Due to Cross-Phase-Modulation in the Normal Dispersive Optical Fibers

A new method is proposed to compress soliton pulses in the normal dispersive optical fibers through cross-phase-modulation of two pulses. The optimum fiber length for optimum compression is obtained for given values of the pulses and fiber parameters.

Higher-order coherent anti-Stokes and Stokes Raman scattering spectra

An investigation was made of the higher-order (up to sixth) spectra of coherent anti-Stokes and Stokes Raman scattering in calcite.

Spectroscopy of Higher Order CARS and CSRS

We report here the experimental results of higher order coherent Raman scattering (CRS) in the calcite with a YAG laser CARS system. The 1st to 6th order CARS and 1st to 2nd order CSRS were observed.The cascade four-wave mixing is the dominant process.