Today, I attempted to replicate the results of
this paper in an experimental physics class at MIT. I asked some of my graduate student friends and eventually found someone in a chemistry group who was willing to give me a small sample of CdSe quantum dots with 625 nm emission. Unfortunately, the experiment did not work in our optical trap in the time I had to test it and I had to abandon the project. (I think our trapping laser was not powerful enough to access the two-photon absorption process. The photodetector was probably not sensitive enough either.)
I did, however, take some nice photos of the fluorescing quantum dots. I used a 405 nm flashlight to excite the dots. I noticed they will even fluoresce a tiny amount from indirect sunlight on a cloudy day.
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| CdSe quantum dots in hexane with no excitation. |
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| CdSe quantum dots excited with a 405 nm flashlight. Fluorescence should be about 625 nm. |
