| Summary: | 碩士 === 國立清華大學 === 光電工程研究所 === 103 === Controlling random laser is tone of the important topics in this field, which may lead to more applications and developments. In this work, we demonstrate the control of random laser by two different mechanisms.
The first mechanism to control the performance of random laser via an optical route. We use a photoreduction method to synthesize silver nanoparticles(NPs) in biopolymer based on deoxyribonucleic acid, which is used as a growing template. The photoreduction time can change the size, shape and number of NPs, and consequently the performance of random laser is changed by optically-controlled scatterers. The pumping energy threshold, emission wavelength and power Fourier transform are analyzed to evaluate the tunability of random lasers with respect to photoreduction time.
The second mechanism is that we utilized electric field to control random laser. We design a structure of parallel plates and add solution mix polystyrene particles and Rh6G（rhodamine 6G）laser dye into gap of parallel plates. Then, different magnitude of electric field is applied to influence the distribution of polystyrene particles based on dielectrophoresis effect. The random lasing modes are changed because of different distribution of polystyrene particles. The mean free path and power Fourier transform of random laser spectra are analyzed to evaluate how the random laser can be controlled by an applied electric field.
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