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Credit: by Changrui Liao, Cong Xiong, Jinlai Zhao, Mengqiang Zou, Yuanyuan Zhao, Bozhe Li, Peng Ji, Zhihao Cai, Zongsong Gan, Ying Wang and Yiping Wang
Microelectromechanical systems (MEMs) have fueled advances in almost every field of science and technology over the past few decades. Cantilevers are ultrasensitive MEM devices used widely as atomic force microscope (AFM) probes. However, there are some challenges around microcantilever systems, so there is a desperate need to develop a new generation of technologies.
Cantilevers are usually formed using a dedicated microfabrication process. They are then mounted and aligned manually within the entire optomechanical system. As a result, it is a bulky system that is laborious to operate. Fortunately, integrating a microcantilever beam into optical fiber will result in optical micro-mechanical devices that are much smaller and cheaper, with stronger signal processing.
In a new paper published in Light: Advanced Manufacturing, a research team led by Professor Yiping Wang from the Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Guangdong Province, College of Physics and Optoelectronic Engineering, Shenzhen University has determined the vital mechanical properties of 3D printed microcantilevers. The paper, titled "Design and realization of 3D printed fiber-tip microcantilever beam probes applied to hydrogen sensing," incorporated the use of a palladium film and different shapes to determine the impact.
The research team fabricated microcantilevers with three different tips using laser-induced two-photon polymerization additive manufacturing. Those tips were rectangular solid, rectangular hollow, and triangular shapes. The team measured the deformation of each microcantilever through an optical interference readout. As a result, they were able to modify the cantilevers by coating them with a palladium film. A palladium film was used to absorb hydrogen, thereby supporting the sensing of hydrogen levels in the immediate area.
Each sensor used optical fiber and measured the levels of optical interference—the amount of light that interfered with the original beams. Light reflected from the top and bottom cantilever surfaces interfered with the light reflected from the fiber end face. The deflection of the cantilever can accurately indicate the concentration of hydrogen in the environment.
The sensors exhibited low humidity cross-sensitivity, making them suitable for real-time monitoring of hydrogen concentrations in respiratory therapy. The soft polymer microcantilever probe could be used for any effect that creates a stress difference. Optical fibers suit AFM systems and update precision measurements through imaging instruments. Their use is continually shown to be excellent in fields such as scanning probes and endoscopes.
Journal
Light: Advanced Manufacturing