Tsinghua University has made progress in laser micro-nano manufacturing research. The relevant research results were published in the international academic journal "Small" (2023, 19, 2205696) under the title "Laser Induced Coffee-Ring Structure through Solid-Liquid Transition for Color Printing". Selected as journal cover article (front cover).
In daily life, when coffee drips on the table, due to the "coffee ring effect" in the material migration process, a ring-shaped "coffee ring" can be formed after volatilization. This study uses ultrafast laser micro-nano processing technology combined with transient solid-liquid transition control to achieve ultrafast laser processing of micron-scale "coffee rings" on a solid matrix. This method can be used to perform precision patterning laser processing on a larger area (more than 2 inches) on metals such as copper, aluminum, and semiconductors, and to achieve patterned color printing applications. This technology has many applications in machinery, optics, and information. It has application potential in other fields.
