Shi Jinwei

Detection of Perfect Cloak in Time Domain

We propose a method for detecting perfect invisible cloak based on the scattering of the materials of the cloak. The position of the detected cloak can also be determined. The demonstration shows that the detecting effect is obvious, and the accuracy of the detection is high.

Theoretical Analysis of the Critical Phenomena of a Brillouin Laser

The critical phenomena of a Brillouin laser are analyzed theoretically. The results show that the behavior of a Brillouin laser in the threshold region is a second-order phase transition. The critical point of the phase transition is the gain threshold of the Brillouin laser, and the order parameter is the amplitude of the Stokes component in stimulated Brillouin scattering. The critical slow-down phenomenon and the typical characteristics in phase transition are demonstrated. Further work on the combination of nonlinear optics and phase transition in the Brillouin laser may lead to a new view and findings that could be significant for both fields.

Wavelength Variation of a Random Laser with Concentration of a Gain Material

The wavelength variation of a laser-dye-type random laser is observed experimentally. It is found that the emitting wavelength of a random laser changes with the change of concentration of the gain material. Also, the actual radiation wavelength is influenced by the pumping rate of the source, the cavity competition and the concentration of scatterers.