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.In particular,recent emergence of various nonl...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.In particular,recent emergence of various nonlinear,transient and complex mechanical dynamics,such as anharmonic vibrations in mechanical resonators,has necessitated real-time surface deformation imaging with higher axial and lateral resolutions,speed,and dynamic range.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.Here,by exploiting the electro-optic sampling with a frequency comb,we demonstrate a line-scan time-of-flight(TOF)camera that can simultaneously measure the TOF changes of more than 1000 spatial coordinates with hundreds megapixels/s pixel-rate and sub-nanometre axial resolution over several millimetres field-of-view.This unique combination of performances enables fast and precise imaging of both complex structures and dynamics in three-dimensional devices and mechanical resonators.展开更多
Precise and stable synchronization between an optical frequency comb(femtosecond mode-locked laser oscillator or microresonator-based comb) and a microwave oscillator is important for various fields including telecomm...Precise and stable synchronization between an optical frequency comb(femtosecond mode-locked laser oscillator or microresonator-based comb) and a microwave oscillator is important for various fields including telecommunication, radio astronomy, metrology, and ultrafast X-ray and electron science. Timing detection and synchronization using electro-optic sampling with an interferometer has been actively used for low-noise microwave generation, long-distance timing transfer, comb stabilization, time-of-flight sensing, and laser-microwave synchronization for ultrafast science facilities. Despite its outstanding performance, there has been a discrepancy in synchronization performance of more than 10 dB between the projected shot-noise-limited noise floor and the measured residual noise floor. In this work, we demonstrate the shot-noise-limited performance of an electro-optic timing detector-based comb-microwave synchronization, which enabled an unprecedented residual phase noise floor of -174.5 dBc∕Hz at 8 GHz carrier frequency(i.e., 53 zs∕Hz^(1/2)timing noise floor), integrated rms timing jitter of 88 as(1 Hz to 1 MHz), rms timing drift of 319 as over 12 h, and frequency instability of 3.6 × 10^(-20) over 10,000 s averaging time. We identified that bandpass filtering of the microwave signal and optical pulse repetition-rate multiplication are critical for achieving this performance.展开更多
基金This research was supported by the National Research Foundation of Korea(Grants 2021R1A2B5B03001407 and 2021R1A5A1032937 for J.K,2021R1A4A1031660 for H.Y,2020R1A2C3004885 for J.L.)。
文摘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.In particular,recent emergence of various nonlinear,transient and complex mechanical dynamics,such as anharmonic vibrations in mechanical resonators,has necessitated real-time surface deformation imaging with higher axial and lateral resolutions,speed,and dynamic range.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.Here,by exploiting the electro-optic sampling with a frequency comb,we demonstrate a line-scan time-of-flight(TOF)camera that can simultaneously measure the TOF changes of more than 1000 spatial coordinates with hundreds megapixels/s pixel-rate and sub-nanometre axial resolution over several millimetres field-of-view.This unique combination of performances enables fast and precise imaging of both complex structures and dynamics in three-dimensional devices and mechanical resonators.
基金National Research Foundation of Korea (NRF-2021R1A2B5B03001407, NRF-2021R1A5A1032937)。
文摘Precise and stable synchronization between an optical frequency comb(femtosecond mode-locked laser oscillator or microresonator-based comb) and a microwave oscillator is important for various fields including telecommunication, radio astronomy, metrology, and ultrafast X-ray and electron science. Timing detection and synchronization using electro-optic sampling with an interferometer has been actively used for low-noise microwave generation, long-distance timing transfer, comb stabilization, time-of-flight sensing, and laser-microwave synchronization for ultrafast science facilities. Despite its outstanding performance, there has been a discrepancy in synchronization performance of more than 10 dB between the projected shot-noise-limited noise floor and the measured residual noise floor. In this work, we demonstrate the shot-noise-limited performance of an electro-optic timing detector-based comb-microwave synchronization, which enabled an unprecedented residual phase noise floor of -174.5 dBc∕Hz at 8 GHz carrier frequency(i.e., 53 zs∕Hz^(1/2)timing noise floor), integrated rms timing jitter of 88 as(1 Hz to 1 MHz), rms timing drift of 319 as over 12 h, and frequency instability of 3.6 × 10^(-20) over 10,000 s averaging time. We identified that bandpass filtering of the microwave signal and optical pulse repetition-rate multiplication are critical for achieving this performance.
