Fig. 4: Measured optomechanics of silica and Janus particles near an ONF.
From: Evanescent field trapping and propulsion of Janus particles along optical nanofibers
Input beam 1 was V-polarized, and we used dedicated samples labeled as ONF1 and ONF2 for the gold coating thickness of 10 nm and 20 nm, respectively (see Supplementary Movie 2). a Sample position-time series for the longitudinal direction of the particle motion at a transmitted optical power of 50 mW. Markers indicate the z coordinate of the particle’s center (with respect to that in the first frame); lines refer to the best linear fit to the data. b Propulsion speed as a function of the particle’s position along the ONF waist. Lines indicate the mean speed values which are (in units of μm s−1): 〈VJP,z〉∣ONF1 = 51.1, 〈VSP,z〉∣ONF1 = 31.4, 〈VJP,z〉∣ONF2 = 71.1, and 〈VSP,z〉∣ONF2 = 30.0. c, d Propulsion speed, Vz, is proportional to the transmitted optical power. e Propulsion enhancement factors, ξz, are nearly constant throughout the explored range of power, averaging at (horizontal lines) 1.51 ± 0.16 and 1.95 ± 0.34 for 10-nm- and 20-nm-thick coating, respectively. Markers and error bars in (c–e) respectively indicate the mean values and the 50% standard deviation ranges obtained for a sample of 5–7 different JPs or 2–6 different SPs for each power value measured in transmission through the ONF.
