High-speed and high-resolution imaging of surface profiles is critical for the investigation of various structures and mechanical dynamics of micro- and nano-scale devices. However, real-time capturing of fast and complex mechanical dynamics has been challenging, and direct time-domain imaging of displacements and mechanical motions has been a missing element in studying full-field structural and dynamic behaviours. 

In a new paper published in Light: Science & Applications, a joint research team at Korea Advanced Institute of Science and Technology (KAIST) and Korea Research Institute of Standards and Science (KRISS), led by Prof. Jungwon Kim at KAIST, reported a new class of line-scan time-of-flight (TOF) camera technology that can capture both static and dynamic properties of micro-scale devices with high dynamic range. 

The new method can simultaneously detect TOF changes of more than 1000 spatial coordinates over several millimetres field-of-view (FOV) with a unique combination of pixel-rates (up to 260 megapixels/s), axial resolution (down to 330 pm) and dynamic range up to 126 dB. This unprecedented combination of performances enables not only fast and precise imaging of complex structures but also real-time observation of fast and non-repetitive mechanical motions in micro-scale devices and mechanical resonators. 

“With our new approach, we can now observe many interesting mechanical phenomena inside MEMS or micro-resonator devices that were difficult to see with existing methods,” said Professor Kim, “which, we anticipate, will open up new powerful metrology technology in the near future.”

Schematic of the demonstrated ultrafast, massively parallel TOF camera and its applications in 3D surface profile imaging and real-time dynamics imaging.

[Reference] Y. Na, H. Kwak, C. Ahn, S. Lee, W. Lee, C. Kang, J. Lee, J. Suh, H. Yoo, and J. Kim, “Massively parallel electro-optic sampling of space-encoded optical pulses for ultrafast multi-dimensional imaging,” Light: Science & Applications (2023). https://doi.org/10.1038/s41377-023-01077-7 

[Main Author] Yongjin Na (KAIST), Jungwon Kim (KAIST)

* Contact : Prof. Jungwon Kim, jungwon.kim@kaist.ac.kr