Loading...

Picosecond and Tunable Distributed Feedback Dye Lasers

Pasandideh, Kaveh | 2018

729 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 50772 (04)
  4. University: Sharif University of Technology
  5. Department: Physics
  6. Advisor(s): Sadighi Bonabi, Rasoul
  7. Abstract:
  8. Distributed feedback dye lasers are among the suitable candidates for spectroscopic applications due to their capability of producing widely tunable picosecond pulses in UV-IR region. However, the pulsewidth sensitivity of the laser to pump intensity fluctuations hinders its suitability for precision applications. In this thesis, by utilizing widely used Self Q-Switching model, we showed that if the dye solution is pumped by a narrow (sub-nanosecond) pulse, the laser can operates in the single-pulse output mode with a better stability over a wide range of pump intensity. After that, we used a dynamical model based on the induced polarization and Maxwell equations, where the obtained results of the numerical solution with two different methods indicate that the laser temporal output profile is mostly determined by the concentration of dye solution and the lifetime of the upper laser level of dye molecules. In the case of low lifetime of the upper laser level, the sequential energy pattern of spikes in laser output was not observed. In addition, as the concentration of dye molecules in dye solution increases, the non-sequential profile appears in lower pump levels. These results agree with the experimental studies even at high-intensity pumping where the Self Q-Switched model fails to be applied. Moreover, a tunable and narrow linewidth dye laser was designed and constructed using two different configurations of multiple-prism beam expander. In the case of two-prism configuration, the tuning range of dye laser was 565-595¬nm and the linewidth of the laser pulse at 580-nm was about 1.8¬nm; that is in the good agreement with the calculated amount of 1.66¬nm. In addition, in four-prism configuration the tuning range of 570-585¬nm was measured and the linewidth of the output pulse at 575nm was reduced to 0.33nm which is slightly different from the theoretical value of 0.22nm
  9. Keywords:
  10. Dye Lasers ; Distributed Feedback Dye Lasers (DFDLS) ; Temporal Output Profile ; Multiprism Beam Expander

 Digital Object List

 Bookmark

No TOC