Damping vibration of scanning near-field optical microscope probe using the Timoshenko beam model

The effect of interactive damping on the flexural vibration frequency for the scanning near-field optical microscope (SNOM) fiber probe based on the Timoshenko beam theory, including the effects of shear deformation and rotary inertia, has been analyzed. In the analysis, the effects of the transverse contact stiffness, damping factor and the ratio of different probe dimensions on the damping vibration frequency were studied. The results show that increasing the ratio of probe length to radius increases the damping vibration frequency of mode 1. Besides, the damping vibration frequencies, based on the Bernoulli-Euler beam theory and the Timoshenko beam theory, are compared. When the contact stiffness is very large for the higher modes, the effects of shear deformation and rotary inertia on the frequency becomes significant. Furthermore, increasing the damping factor increases the vibration frequency. The trend is more obvious, especially dimensionless damping factor η_f>0.4.