| Summary: | 碩士 === 國立清華大學 === 物理學系 === 106 === Rydberg atoms exhibit several exaggerated properties such as large dipole moments which are interesting to fundamental physics and quantum technology application. Strong dipole-dipole interaction is important in quantum gate which is an essential key to the quantum computer. Heteronuclear is also an important issue in quantum readout, which is one of the solutions for distinguishing controlled and target atoms. Hence, to study the inter species Rydberg interaction and to produce heteronuclear Rydberg molecules are expected to be important for future quantum information technique development. Our research directs to the Rydberg interaction of K-Rb and to produce KRb heteronuclear Rydberg molecule. In this thesis, as the initialization of such a research, we report the first realization of the cold potassium Rydberg atoms. Firstly, in the hot cell experiment, we study Rydberg-Double Resonance Optical Pumping (DROP) scheme which is similar to EIT but with open channel and higher probe power. Our experimental system is based on an inverted ladder type scheme and room temperature potassium atoms. The laser system consist of two homemade external-cavity-diode-laser (ECDL). One of the laser wavelength is 404 nm, which is resonance to potassium 4S → 5P transition. And a nearinfrared laser system NIR laser, to couple the intermediated state(5P) and Rydberg states, is composed of an ECDL and a tapered amplifier to reach 1 W. By optical Bloch equation, we have developed a theoretical model for the Rydberg-DROP scheme. To verify the theoretical model, we have demonstrated good agreements the model and experimental result in the Rydberg-DROP spectrum and the fluorescence spectrum. Finally, with a magneto-optical trap to produce a cold potassium of 200 µK, we observed four Rydberg transitions, including 70S and 68D using trap loss signals. The cold Rydberg potassium is therefore demonstrated.
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