Total internal reflection is an optical imaging technique for nanoparticle tracking and observation employing the scattered light from an evanescent field near the interface or reference surface. Generally, the nanoparticle behavior is the three-dimensional Brownian motion in an aqueous medium. The motion can be traced by an optical microscopy, but it cannot be traced by an electron microscopy technique. In the three-dimensional nanoparticle moving position, the X and Y positions are parallel to the surface, which can be traced by the general microscopy techniques. However, the height position Z of a nanoparticle perpendicular to the surface could not be traced without the longitudinal scanning method. Here, a novel method is proposed to investigate the 3D position of nanoparticles by applying multi-wavelength evanescent fields microscopy, which has a high spatial resolution in the Z-direction without longitudinal scanning. This paper focuses on the verification of measurement in the Z-direction. A piezoelectric actuator was employed to control the nanoparticle displacement in height Z. Standard polystyrene 100 nm particles were randomly adhered on a spherical tip that connected with the piezoelectric actuator. The spherical tip was essentially made from an optical adhesive (n = 1.348) with a refractive index close to the water for decreasing the unnecessary signal from the tip-self during nanoparticle observation in the water. The proposed method could obtain the multi-wavelength scattering lights from the observed nanoparticles by an 8-bit color camera with higher than 50 frames per second recording to investigate the 3D nanoscale tracking. The X and Y positions of nanoparticles were determined by the centroid of the scattering light intensities. The height Z was determined from the logarithm ratios between the detected scattering light intensities of both wavelengths. The measurement repeatability of the absolute difference in height between nanoparticles could be measured less than ±16 nm by using the proposed method. The penetration height measurability range was approximated at 250 nm from the reference surface.

1. [1] K. Kimura, Y. Hashiyama, P. Khajornrungruan, H. Hiyama, and Y. Mochizuki, “Study on Material Removal Phenomena in CMP Process,” Proc. of the Int. Conf. on Planarization/CMP Technology (ICPT 2007), pp. 201-205, 2007.
2. [2] ISO 21501-2: 2019 “Determination of particle size distribution – Single particle light interaction methods – Part 2: Light scattering liquid-borne particle counter,” 2019.
3. [3] P. A. Temple, “Total internal reflection microscopy: a surface inspection technique,” Applied Optics. Vol.20, pp. 2656-2664, 1981.
4. [4] C. T. McKee, S. C. Clark, J. Y. Walz, and W. A. Ducker, “Relationship between scattered intensity and separation for particles in an evanescent field,” Langmuir, Vol.21, pp. 5783-5789, 2005.
5. [5] L. Helden et al., “Single-particle evanescent light scattering simulations for total internal reflection microscopy,” Applied Optics, Vol.45, pp. 7299-7308, 2006.
6. [6] J. A. Thorley, J. Pike, and J. Z. Rappoport, “Fluorescence Microscopy: Super-Resolution and other Novel Techniques,” Elsevier, pp. 199-212, 2014.
7. [7] Y. Kazoe and M. Yoda, “Evanescent wave-based flow diagnostics,” J. of Fluids Engineering, Vol.135, No.2, 021305, 2013.
8. [8] C. M. Zettner and M. Yoda, “Particle velocity field measurements in a near-wall flow using evanescent wave illumination,” Experiments in Fluids, Vol.34, pp. 115-121, 2003.
9. [9] T. Yoshioka, T. Miyoshi, and Y. Takaya, “Particle Detection for 100-nm Patterned Wafers by Evanescent Light Illumination – Analysis of Evanescent Light Scattering Using Finite-Difference Time-Domain Method –,” J. Robot. Mechatron., Vol.18, No.6, pp. 705-713, 2006.
10. [10] P. Khajornrungruang, P. J. Dean, and S. V. Babu, “Study on dynamic observation of sub-50 nm sized particles in water using evanescent field with a compact and mobile apparatus,” Proc. of ASPE 2014 Annual Meeting, pp. 73-76, 2014.
11. [11] D. Bachurski et al., “Extracellular vesicle measurements with nanoparticle tracking analysis – an accuracy and repeatability comparison between nanosight NS300 and zetaview,” J. Extracell Vesicles, Vol.8, 1596016, 2019.
12. [12] P. Khajornrungruang, H. Shirakawa, K. Suzuki, and R. Takemoto, “Proposal of individual sub 100 nm nano-particle 3D-tracking method in multi wavelength evanescent fields” Proc. of ADMETA Plus Asian Session 2017, pp. 86-87, 2017.
13. [13] A. Blattler, P. Khajornrungruang, K. Suzuki, and T. Permpatdechakul, “Study on on-machine visualization of surface processing phenomena in nanoscale,” Proc. of JSPE Semestrial Meeting, Vol.2019S, pp. 459-460, 2019.
14. [14] A. Blattler P. Khajornrungruang, K. Suzuki, and T. Permpatdechakul, “High-speed three-dimensional tracking of individual 100 nm polystyrene standard particles in multi-wavelength evanescent fields,” Meas. Sci. Technol., Vol.31, 094012, 2020.
15. [15] T. Kurihara, R. Sugimoto, R. Kudo, S. Takahashi, and K. Takamasu, “Height measurement of single nanoparticles based on evanescent field modulation,” Int. J. Nanomanuf., Vol.8, pp. 419-431, 2012.
16. [16] K. Kanda, S. Ogata, K. Jingu et al., “Measurement of particle distribution in microchannel flow using a 3D-TIRFM technique,” J. Vis., Vol.10, pp. 207-215, 2007.
17. [17] M. K. Cheezum, W. F. Walker, and W. H. Guilford, “Quantitative comparison of algorithms for tracking single fluorescent particles,” Biophys J., Vol.81, No.4, pp. 2378-2388, 2001.
18. [18] A. Von Diezmann, Y. Shechtman, and W. E. Moerner, “Three-dimensional localization of single molecules for super-resolution imaging and single-particle tracking,” Chem. Rev., Vol.117, pp. 7244-7275, 2017.