Asymmetric microcavities supporting Whispering-gallery modes (WGMs) are of great significance for on-chip optical information processing. We establish asymmetric microcavities on topologically curved surfaces, where the geodesic light trajectories completely reconstruct the cavity mode features. The curvature-mediated photon-lifetime engineering enables the enhancement of the quality factors of periodic island modes by up to 200 times. Strong and weak coupling between modes of very different origins occurs when the space curvature brings them into resonance, leading to fine tailoring of the cavity photon energy and lifetime and the observation of non-Hermitian exceptional point (EP). At large space curvatures, the role of the WGMs is replaced by high-Q periodic modes protected by the high stability of island-like light trajectory. Our work demonstrates interesting physical mechanisms at the crosspoint of optical chaotic dynamics, non-Hermitian physics, and geodesic optical devices, and would initiate the novel area of geodesic microcavity photonics.

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To depict the evolution of the global trade of traditional Chinese medicine (TCM) products, this article analyzes the 2001–2020 trade data of TCM products in the World Bank and United Nations Commodity Trade Statistics Database to discern the spatial-temporal evolution characteristics of global and China's trade patterns of TCM products from 2001 to 2020 and thereby assess the changes in the global trade of TCM products and in the positions of various countries or regions in the global trade of TCM products. Research findings are as follows: First, on the whole, the total trade volume of TCM products and the number of participating economies and trade connections are on the rise. Second, in terms of topological structure, with higher network density and rising transmission efficiency, the global trade network of TCM products has typical small-world and scale-free network characteristics and has begun to be controlled by a few countries. Judging from the co-opetition between major trading countries, there are more diversified sources of imports for major trading countries, and there is competition between supplying countries. Third, For China, the trade volume of TCM products between China and various countries worldwide has grown rapidly and exhibits a trend of continuous increase followed by decline. China has established extensive trade partnerships and its position in the global trade network of TCM products has been continuously improved. China's participation has contributed to a closer connection among trading entities, but its network heterogeneity remains to be further improved. From the perspective of trade interdependence, the number of countries or regions maintaining high interdependence with China has been gradually increasing, and most of them are European and American countries, Japan, and Southeast Asian countries. The number of countries or regions maintaining low interdependence with China has gradually decreased, and countries or regions that are completely one-way dependent on China are nonexistent.

Asymmetric microcavities supporting Whispering-gallery modes (WGMs) are of great significance for on-chip optical information processing. We establish asymmetric microcavities on topologically curved surfaces, where the geodesic light trajectories completely reconstruct the cavity mode features. The curvature-mediated photon lifetime engineering enables the enhancement of the quality factors of periodic island modes by up to 200 times. Strong and weak coupling between modes of very different origins occur when the space curvature brings them into resonance, leading to a fine tailoring of the cavity photon energy and lifetime and the observation of non-Hermitian exceptional point (EP). At large space curvatures, the role of the WGMs is replaced by high-Q periodic modes protected by the high stability of island-like light trajectory. Our work demonstrates interesting physical mechanism at the crosspoint of optical chaotic dynamics, non-Hermitian physics and geodesic optical devices, and would initiate the novel area of geodesic microcavity photonics.

No abstract