An optically actuated surface scanning probe
An optically actuated surface scanning probe
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DOI：
10.1364/oe.20.029679
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发表时间：
2012-12-31
期刊：
影响因子：
3.8
通讯作者：
Simpson, S. H.
中科院分区：
文献类型：
--
作者：
Phillips, D. B.;Gibson, G. M.;Simpson, S. H.
We demonstrate the use of an extended, optically trapped probe that is capable of imaging surface topography with nanometre precision, whilst applying ultra-low, femto-Newton sized forces. This degree of precision and sensitivity is acquired through three distinct strategies. First, the probe itself is shaped in such a way as to soften the trap along the sensing axis and stiffen it in transverse directions. Next, these characteristics are enhanced by selectively position clamping independent motions of the probe. Finally, force clamping is used to refine the surface contact response. Detailed analyses are presented for each of these mechanisms. To test our sensor, we scan it laterally over a calibration sample consisting of a series of graduated steps, and demonstrate a height resolution of similar to 11 nm. Using equipartition theory, we estimate that an average force of only similar to 140 fN is exerted on the sample during the scan, making this technique ideal for the investigation of delicate biological samples. (C) 2012 Optical Society of America
