arXiv subjects

C. -H. Kuo

Publications and source records attributed to C. -H. Kuo.

4 recordsLinked to original sources

arXiv2024

Preparing pure $^{43}$Ca$^+$ samples in an ion trap with photoionization and parametric excitations

We present a practical scheme for the efficient preparation of laser-cooled $^{43}$Ca$^+$ ions in an ion trap. Our approach integrates two well-established methods: isotope-selective photoionization and isotope-specific parametric excitation. Drawing inspiration from the individual merits of each method, we have successfully integrated these techniques to prepare extended chains of $^{43}$Ca$^+$ ions, overcoming the challenge posed by their low natural abundance of 0.135\% in a natural source. Furthermore, we explore the subtleties of our scheme, focusing on the influence of different factors on the purification process. Our investigation contributes to a broader understanding of the technique and highlights the adaptability of established methods in addressing specific isotopic challenges.

physics.atom-ph↗

arXiv2021

Lithium-cesium slow beam from a two-dimensional magneto-optical trap

We present the creation of a lithium-cesium slow beam using a two-dimensional magneto-optical trap. The two-species atomic beam is directed to load a three-dimensional magneto-optical trap in ultrahigh vacuum. We achieve a loading rate of 1.3$\times$10$^{7}$ lithium atoms/s with the lithium oven temperature at 370~$^{\circ}$C and 2.2$\times$10$^{7}$ cesium atoms/s with the Cs oven temperature at 20~$^{\circ}$C. The maximum numbers of lithium and cesium atoms in the trap are 1.0$\times$10$^{9}$ and 1.4$\times$10$^{8}$, respectively. Our results show that the simple and compact two-dimensional magneto-optical trap is suitable for producing an atomic beam of two species that have a large mass ratio and very different volatilities.

physics.atom-ph↗

arXiv2003

Comment on "Total Negative Refraction in Real Crystals for Ballistic Electrons and Light" (Phys. Rev. Lett. 91, 157404 (2003))

Recently, Zhang et al. (Phys. Rev. Lett. 91, 157404 (2003)) have demonstrated that an amphoteric refraction, i. e. both positive and negative refraction, may prevail at the interface of two uniaxial anisotropic crystals when their optical axes are in different directions. The authors subsequently made a correspondence between such a refraction with the negative refraction expected for Left Handed Materials (LHMs). Here we comment that the amphoteric refraction can be observed even with one uniaxial crystal, and the refraction is not related to the negative refraction expected for the much debated LHM. Rather, the phenomenon is a natural result of anisotropic media.

cond-mat↗

arXiv2003

Band gap or negative refraction effects?

By a rigorous numerical simulation based on the standard multiple scattering theory, we investigate the optical transmission in photonic crystal structures, formed by dielectric cylinders embedded in parallel in a uniform medium. In contrast to previous conjectures, the results indicate that the imaging effect which has been interpreted as a signature of the negative refractive effects is caused by a tunnelling effect in the presence of partial band gaps. There is no need for an all-angle negative refraction effect to understand some peculiar phenomena of photonic crystals.

cond-mat↗