The breakthrough made in bridging the gap between the laser frequencies and the microwave time standard by exploiting the frequency comb of a femtosecond laser has brought a drastic improvement in the precision of optical interferometers. The femtosecond laser offer unique temporal and spectral characteristics: short pulse duration, high peak power, broad spectral bandwidth, and low frequency instability. Femtosecond lasers, therefore, are being used for various applications such as precision time and frequency metrology, absolute ranging, and optical communication. This advance attracts much attention to extend today’s space missions by improving the precision of remote sensing and control capabilities. Together with that, femtosecond lasers can also provide novel possibilities to optical profilometry both in the time and the frequency domain. In the time domain, step-surfaces can be measured over wide area by exploiting low temporal but high spatial coherence of femtosecond pulses; in the frequency domain, multi-wavelength interferometry permits the absolute measurement over the discontinued surface profiles while maintaining the sub-wavelength measurement precision.

报告人简介：

Young-Jin KIM is a Nanyang Assistant Professor and a NRF Fellow in School of Mechanical and Aerospace Engineering (MAE) in Nanyang Technological University (NTU), Singapore. He received his Bachelor, Master, and Ph. D degrees from Korea Advanced Institute of Science and Technology (KAIST), South Korea. He has actively participated in the field of the ‘ultrafast photonics’ since 2004; developed a series of optical frequency comb; established the ‘definition of a meter’ in real world by precisely measuring absolute length and surface profiles using frequency combs; expanded the wavelength regime of the frequency comb into EUV regime by plasmonic field enhancement; demonstrated the world-first femtosecond laser system in outer space. He will establish ‘ultra-precision’ based on ‘ultrafast photonics’ in NTU for mass production of next-generation semiconductor, flat-panel display, photovoltaic products and advance the ‘ultrafast photonics’ technology for bio-medical diagnosis and future space LIDARs.