Development and application of saturable absorbers to femtosecond solid-state laser mode-locking

Semiconductor saturable absorbers have had a major impact on the field of ultrashort pulse generation by increasing the stability and reliability of ultrashort pulse lasers, making them more useful in many applications. These versatile devices can be grown both epitaxially with molecular beam epitaxy and non-epitaxially using RF sputtering. In this thesis, the development and application of both types of saturable absorbers to self-starting mode-locking in solid-state lasers was examined. The first part of this thesis describes the use of an epitaxially grown saturable Bragg reflector to mode-lock an extended cavity femtosecond Cr:LiSAF laser. Inexpensive single mode diodes were used as a pump source and a multi-pass cavity was used to lower the laser repetition rate. Pulses with durations of 39 fs and energies of 0.75 nJ were generated at an 8.6 MHz repetition rate. These pulse energies and durations are comparable to those produced from commercially available Ti:sapphire lasers that have a significantly higher cost. The second part of this thesis explored the further development and application of non-epitaxially grown semiconductor-doped silica films. A novel pump-probe system with independent pump and probe wavelength tunability from 700 to 1000 nm and a time resolution of 17 fs was developed for device characterization. The linear and nonlinear optical properties of InAs-doped silica films deposited by RF sputtering were characterized as a function of fabrication parameters, including nanocrystallite size, pump and probe wavelength relative to the absorption edge, and rapid thermal annealing temperature. Guidelines for the optimization of semiconductor-doped silica films for saturable absorber applications were extracted from the experimental data.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2003

Author dc:creator

• Prasankumar, Rohit Prativadi, 1975-

Advisor dc:contributor.advisor

• James G. Fujimoto.

• Electrical Engineering and Computer Science.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/29620

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/29620