Lin Dian-Yang

Pulse Compression Based on Laser-Induced Optical Breakdown in Suspension

Pulse compression based on laser-induced optical breakdown in suspension is investigated. The physical mechanism behind it is analyzed theoretically and validated in the Q-switched Nd:YAG laser system. A 12-ns pump pulse is suppressed to 5 ns with good fidelity in the front edge and sharp steepness in the trailing edge. The HT-270, which has a small gain coefficient and absorption coefficient, is used as a solvent, and therefore the disturbance induced by stimulated Brillouin scattering and absorption are minimized and the transmittivity is enhanced.

Investigation of stimulated rotational Raman scattering of the high-power broadband laser with applied angular dispersion

Smoothing by spectral dispersion (SSD) leads to considerable improvement on laser-irradiation uniformity in far field for fusion lasers. Phase modulation in time and spectral angular dispersion (SAD) across the beam introduced by SSD will affect the stimulated rotational Raman scattering (SRRS) gain in the near field. This paper focuses on the influence of SAD on SRRS gain under different laser conditions. Results show that the SAD will aggravate the generation of SRRS when the laser initial additional phase is constant. On the contrary, the SAD can reduce the SRRS gain if appropriate SSD parameters are adopted when the laser initial additional phase is variable. SSD has a certain application prospect in SRRS suppression.

Investigation of stimulated Brillouin scattering for broadband KrF laser

Stimulated Brillouin scattering (SBS) numerical mode for broadband multimode KrF laser pump with optical breakdown has been built up in this paper. The basic premises of the mode are that KrF spectrum is composed of a number of lines and SBS arises from these lines with coupling to some extent. The broadband SBS threshold strongly depends on pump bandwidth. SBS and optical breakdown occur nearly simultaneously when broadband SBS and breakdown have the same threshold. The decrease of saturation reflectivity for broadband pump radiation is explained with this model. Experimental results agree well with the model.

Investigation of optical limiting based on the combination of stimulated Brillouin scattering and metal-phthalocyanine complexes

In order to improve the optical limiting performance based on stimulated Brillouin scattering (SBS), an optical limiter based on the combination of SBS and metal-phthalocyanine complexes (MPCs) is proposed in this paper. The output energy of the combination optical limiting designed based on SBS followed by MPCs shows flatter characteristic. The dependence of the output energy of optical limiting based on this combination approach on the input light intensity is numerically simulated, and validated in a continuum Nd:YAG seed-injected laser system. The theoretical and the experimental results indicate that the output energy based on this approach has a flatter characheristie than based on a single SBS.

Laser-induced pattern formation from homogeneous polyisoprene solutions

This paper reports that the pattern formation in homogeneous solutions of polyisoprene in toluene saturated with C60 induced by a continuous-wave visible laser is observed experimentally. The transmitted beam patterns change with the increase of the laser irradiation time. In the initial phase, the patterns with concentric ring-shaped structure are formed. In the end, the patterns become speckle-shaped. The incubation time of the transmitted beam widening is inversely proportional to the laser power density and solution concentration. The pattern formation results from the optical-field-induced refractive index changes in the solutions, but the mechanism of optical-field-induced refractive index changes in the polymer solutions needs to be further studied.

Observation of the SRS spectrum of secondary vibrational foundamental frequency ν2 in CH4

With a Q‐switching Ruby laser, the stimulated Raman vibrational line ν of CH4, which was much difficult to observed, was first observe and the scattering feature between CH4 and H2 was compared.