'Pulse Laser' That Measures Down to Nanometers Emerges

[Asia Economy Reporter Junho Hwang] Domestic researchers have developed a pulse laser measurement technology capable of measuring down to the nanometer scale. This technology surpasses the limitations of existing high-performance distance measurement technologies and is expected to be utilized in autonomous driving LiDAR and other applications in the future.

KAIST announced on the 12th that a research team led by Professor Jungwon Kim of the Department of Mechanical Engineering developed an ultra-fast, ultra-precise pulse time-of-flight (TOF) sensor technology for distance measurement using pulse lasers and electro-optic sampling techniques.

Pulse Laser Measurement Technology Capable of Measuring Down to the Nanometer Scale

The research team developed a new type of pulse laser distance measurement technology. It measures the time difference between the light pulse generated by the pulse laser and the current pulse generated by the photodiode using electro-optic sampling techniques. By utilizing this technology, it is possible to precisely measure distance differences smaller than a nanometer at high speed. Additionally, since the current pulse length is longer than several tens of picoseconds, distances of more than millimeters can also be measured.

The pulse time-of-flight sensor is one of the methods used for distance and shape measurement. It measures the time taken for a light pulse to be emitted, reflected off the target, and return, then calculates the distance to the target using the speed of light.

This technology overcomes the limitations of existing high-performance distance measurement technologies. Existing pulse time-of-flight measurement technologies have long measurement distances of over meters but suffer from lower resolution (measurement capability). On the other hand, interferometer technology offers excellent resolution at the nanometer level but can only measure narrow ranges at the micrometer level. Both technologies share the common limitation of slow measurement speeds.

Real-time Measurement Possible

Using the research team’s new pulse time-of-flight sensor technology, position differences as small as 180 picometers (1/5.5 billionth of a meter), smaller than the size of two hydrogen atoms, can be accurately measured within 1/200th of a second.

The research team demonstrated high-resolution 3D shape imaging technology and implemented a high-precision strain sensor that can be used to measure minute deformations such as seismic waves or volcanic activity. Additionally, leveraging the advantage of high resolution even at ultra-high-speed measurements, they achieved real-time measurement of the position of objects changing at speeds exceeding 100 MHz (100 million vibrations per second) with nanometer resolution.

The research team expects this technology to be utilized as a core technology in various fields, including LiDAR used in autonomous driving, semiconductor processes, earthquake detection, gravitational wave detection, and natural phenomenon exploration.

Professor Kim stated, "Our next research goal is to use this technology to measure and elucidate complex and fast dynamic phenomena in real time, such as nonlinear movements within micro devices that were previously unobservable."

Doctoral student Yongjin Na, who participated as the first author, contributed to this research, which was published on the 10th in the journal Nature Photonics.

This content was produced with the assistance of AI translation services.