Page 38 - Undergraduate Research Opportunities Program Proceedings 2017-18

School of Science
Department of Physics

Quantum Optics and Atomic Physics

Supervisor: DU Shengwang / PHYS
Student: LI Bohan / PHYS-IRE Course: UROP2100, Fall
UROP3100, Spring

In this report, we use the rubidium spectrum to illustrate how the external cavity laser is able to lock its frequency at an
absorption peak in the rubidium hyper-fine transition spectrum. We would first introduce the mechanism of the hyper-
fine structure and explain the rubidium transition spectrum. The design of the external cavity diode laser and the locking
technique would also be described.

Supervisor: DU Shengwang / PHYS
Student: ZHU Lingbang / PHYS-IRE Course: UROP3100, Fall
UROP4100, Spring

Entangled photon pair generation has been demonstrated in various systems for quantum optics experiments in the last
decade. A simple and economical way is using atomic vapor cell for four wave mixing scheme. Here we report our
preliminary tests on the performance of biphoton generation from a Rubidium vapor cell with a small phase-
mismatching angle. Good quality electro-magnetically induced transparency could be obtained by adopting a 0-degree
coupling scheme. Two-photon coincidence measurement is carried out and compared with previous results, which
indicates a slightly longer coherence time.

Fabrication of Novel Granular and Colloid Particles

Supervisor: HAN Yilong / PHYS
Student: CHEUNG Chak Lun / PHYS Course: UROP1100, Fall

The project has two main goals: to fabricate thousands to cm-sized soft and hard particles, to design the compression
system for the crystal-to-glass transition experiment. The particles can mimic atoms in crystal-to-glass transitions and
reveal the interesting structure changes at the single particle level. After the setup is prepared, we will track the position
of particles by image processing and obtain several useful parameters, such as susceptibility of orientational order and
density functions, for the quantitative understanding of the structure transition.

Development of Intensity Stabilization System for Optical Cooling of Quantum Gases
Supervisor: JO Gyu Boong / PHYS
Student: CAI Qianhang / PHYS-IRE Course: UROP1100, Fall
UROP2100, Spring

In quantum optics experiments, it is meaningful to perform exquisite light modulation in the scale of atoms, which
requires a through but fine manipulation over beam profiles including both its phase and intensity. In this report, a
method to achieve this purpose with the adoption of DMD and hologram generation is briefly introduced, as well as
some of my current progress in terms of realization.

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