GENERATION AND USE OF FEMPTOSECOND, GIGAWATT, NEAR INFRARED LASER PULSES FROM AN AMPLIFIED, MODE-LOCKED, TI:SAPPHIRE LASER

David Anthony Valdes

Abstract

This work modeled the early to middle successes achieved in the field of ultrafast, high peak power optics, beginning with the work of Nobel Prize winners Donna Strickland and Gérard Mourou in 1985. In our work, 100 fs light pulses of around 800 nm were generated by a Ti:Sapphire oscillator, then amplified to approximately 30 GW peak power using a chirped pulse amplification system that included regenerative and multi-pass amplifiers. As a verification of our pulses having high peak powers and ultrashort durations, they were then used to strike water, glass, and a Kerr Cell. Supercontinuum generation was observed as a result of striking the water and the glass. Moreover, using water produced a stable source of white light. Glass did not produce a stable source of white light due to material damage. In striking the Kerr Cell, we hoped to observe an induced voltage from the interaction of high power pulses with the CS2 contained within. This was not observed. However, spectral components of green, yellow, and red were observed. In addition to the expected results, for several months during the experiment we generated 55 fs pulses. This is an exciting result as pulses of this duration are thought by some to be impossible given the elements used for our system. The precise mechanisms that contributed to the sub-100 fs pulses are yet undetermined. This suggests interesting work for the future of this system given the extra stability it affords as compared to other modern systems. A brief history of this type of laser system is given in Chapter 1 along with some key physical ideas. The components of our systems and principles of operation are discussed in Chapter 2. Data for each part of the experiment is given in Chapter 3. Experimental procedures and selected derivations for mathematical analysis are included in the appendices.