Fig. 6: The position-time response for the periodic mechanical vibration.
From: Single-shot BOTDA based on an optical chirp chain probe wave for distributed ultrafast measurement
a The time evolution for the distributed BGS (the value is increased from blue to red). b The background pattern at the segment of 60–62 m. c The time evolution for the BGS at the segment of 44–46 m. d The time evolution for the BGS at the segment of 4–6 m. e The time evolutions for the distributed BGSs are processed by subtracting the initial distributed BGSs at time t = 0
