Date of Award

Spring 2009

Document Type

Restricted Thesis

Terms of Use

© 2009 Margaret Cosgriff. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Physics & Astronomy Department

First Advisor

Carl H. Grossman


Using a beam-splitter and two photon detectors, we measured the cross-correlation function of a series of single nanocrystals, and found that the nanocrystals exhibit antibunching (zero correlation at zero time delay) as expected, indicating that the nanocrystals were indeed emitting only one photon at a time. Modeling the nanocrystals as a three-level energy system (ground, excited, and "dark"), we measured the characteristic time delay between photons emitted by a nanocrystal, which corresponds to the inverse of the transition rate from the excited state and the ground state. We performed this measurement using 532nm and 405nm wavelength light to excite the nanocrystals. Nanocrystals excited by 532nm wavelength light had a mean time constant of 22.7 ± 5.3ns, and those excited by 405nm wavelength light had a mean time constant of 22.4 ± 6.3ns.