Presentation

Week 1: 5 Feb. 2001

At the middle of this week, I began to read an uncompleted report by Mike Twardos for his NSF summer project in 1999, as well as some references in that report.

Week 2: 12 Feb. 2001

The project seems quite difficult because of its weak signal (<1e-11watt), but it's so interesting, I decided to take it. After talking with Dr. Noe, I got some references (as well as some others I found from INSPEC, PROLA and SPIN websites).

Now I am reading these papers:

R. Corey, M. Kissner, and P. Saulnier, "Coherent Backscattering of Light", American Journal of Physics, Volume 63, Number 6, June (1995).

M. van Albada and A. Legendijk, "Observation of Weak Localization of Light in a Random Medium" Phys. Rev. Lett. 55, 2692 (1985).

G. Maret and P.Wolf, "Wek Localization and Coherent Backscattering of Photons in Disordered Media", Phys. Rev. Lett. 55, 2696 (1985).

P. Saulnier and G. Watson, "Role of Surface Reflectivity in Coherent Backscattering Measurements" Optics Lett. 17, 1(1992).

Week 3: 17 Feb. 2001

I am continuing reading some recently paper including some paper about observation of CBS in laser-cooled cluster.
Now I think the basic sketch of the experiment has been finished. I plan to measure the signal with the instruments below.

Week 4: 24 Feb. 2001

The optical components has been ordered this week!

Week 5: 3 Mar. 2001

I have set up some of optical components, but we found we the polarized light selective beam splitter does not suitable. We have ordered another one.

Week 6: 10 Mar. 2001

Now we have made PMT system work and have made almost everything done. THe only problem is, the crew of quarter wave plate holder is not of US standard. So, it is a little tilted. We can not obtain circular polarized light with it. We are ording some adepters.

Week 7: 17 Mar. 2001

In this week, I made everything work and measured the intensity spatial dependence of scattering light in both vertical and horizontal directions. The results are list below. Also, a step-in motor drived scanning system were setuped to automatically measure the intensity spatial dependence of the scattering light. With this device, a more detailed CBS curve were obtained and the background were subtracted.

Horizontal Direction

Vertical Direction

Automatically Scanned CBS Curve(Horizonal)