College of Science and Health Theses and Dissertations

Date of Award

Summer 8-23-2015

Degree Type


Degree Name

Master of Science (MS)



First Advisor

Eric Landahl, PhD

Second Advisor

Anuj P. Sarma, PhD

Third Advisor

Gabriela B. Gonzalez Aviles, PhD


The semiconductor-doped glass RG850 is a commercially available optical filter material that has recently been found to also be useful as a saturable absorber for intense ultrafast light pulses. This thesis presents the first experimental study of the time-dependent saturable absorption of RG850 and compares it to a simple electronic model. Even at low light intensities, our data display two distinct decay time constants. This may be indicative of the nanocrystalline structure of this material. We find that the slow-time constant is independent of laser intensity (173 +/- 14 ps), but that the fast-time constant decreases with increasing laser intensity. The ultrafast nonlinear response observed implies that RG850 could be useful in optical computing or other high-speed applications, and that further insights into the mechanism could be gained from additional studies such as time-resolved optical and x-ray spectroscopy.

SLP Collection