NONLINEAR LIQUIDS AND MECHANISMS FOR ALL-TIME-SCALE OPTICAL LIMITING EFFECTS
Open Access
- Author:
- Huang, Junbin
- Graduate Program:
- Electrical Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- May 24, 2011
- Committee Members:
- Iam Choon Khoo, Dissertation Advisor/Co-Advisor
Iam Choon Khoo, Committee Chair/Co-Chair
Shizhuo Yin, Committee Member
Zhiwen Liu, Committee Member
Thomas E Mallouk, Committee Member - Keywords:
- optical limiting
nonlinear liquid
L34
metallic nanopartilce dopants - Abstract:
- A nonlinear liquid L34 and its molecular level model which presented two-photon, singlet and triplet excited state absorption were presented. Our quantitative analysis illustrated the dynamic changes in the molecular level population and their critical dependences on the laser intensity and the pulse duration. Empirical experiments were further investigated to verify gold-doped L34 bulk samples transmission clamping performance enhancement compared to that of pure L34 in ultrafast time scale. The influence of the surface plasmon of gold nanoparticles on L34 was explored for a Maxwell-Garnett type composite. We demonstrated that the nonlinear absorption coefficient of the L34+Au composite can be enhanced over a specific spectral range. The presence of metallic nanoparticle dopants will also amplify the conversion from optical energy to heat, which extends the application of metallic doped nonlinear liquid limiters to the range of long time scale or cw lasers. A symmetrized split-step Fourier method was used to model the phase changes while a Gaussian beam propagates through nonlinear bulk samples. A more complicated structure device: a fiber array with L34 doped with Au particles and its limiting performance in a subnanosecond pulse train are also explored in the last chapter.