El. Florin et al., PHOTONIC FORCE MICROSCOPE CALIBRATION BY THERMAL NOISE-ANALYSIS, Applied physics A: Materials science & processing, 66, 1998, pp. 75-78
The forces of a photonic force microscope based on optical tweezers ar
e determined using the Boltzmann distribution of thermally driven posi
tion fluctuations. As a fundamental method, only a minimum of informat
ion about the system is required, i.e. the solution's temperature. Thi
s calibration method provides detailed information about the trapping
potential with nanometer resolution. In contrast to other calibration
methods, no numerical hydrodynamic corrections are necessary. The late
ral force constant of the optical trap was measured along the optical
axis and found to decrease linearly by approximate to 8%/mu m for a la
tex bead 600 nm in diameter. Oscillations in the lateral force constan
t were found along the optical axis close to the surface.