Q-Control, Feedback Cooling, and Nonlinear Dynamics

1. Motivation

The quartz tuning-fork (QTF) is a widely used resonator for sensing applications in scanning probe microscopy (SPM). We demonstrate the Q-control, feedback cooling, and nonlinear dynamics for the quartz tuning-fork by implementing active feedback control scheme. By this work, one can generate the on-demand system by controlling the parameters from the feedback loop. These techniques can apply to the novel measurements in QTF based  scanning probe microscopy such as the fast scanning by compressing the decay time of the probe, the tip-sample interaction force spectroscopy by increasing the dynamic range of the resonator, the high resolution scanning by reducing the thermal noise of the oscillator, and the high sensitive sensor by using the nonlinear phase transition.

* References
1. Junghoon Jahng, Manhee Lee, Hanheol Noh, Yongho Seo, and Wonho Jhe, “Active Q-control in tuning-fork-based atomic force microscopy”, Appl. Phys. Lett. 91, 023103 (2007) [Link]
2. Manhee Lee, Junghoon Jahng, Kyungho Kim, and Wonho Jhe, “Quantitative atomic force measurement with a quartz tuning fork”, Appl. Phys. Lett. 91, 023117 (2007) [Link]

2. Theory and Experimental Setup

1) Q-control

ControlQTF_2_1_QControl.jpg

2) feedback cooling

ControlQTF_2_2_FeedbackCooling.jpg

3) nonlinear dynamics

(1) Duffing Oscillator

ControlQTF_2_3_DuffingOscillator.jpg

(2) Parametric Resonance

ControlQTF_2_4_ParametricResonance.jpg

3. Results and Discussion

1) Q-control

ControlQTF_3_1_QControl.jpg

2) feedback cooling

ControlQTF_3_2_FeedbackCooling.jpg

3) nonlinear dynamics

ControlQTF_3_3_NonlinearDynamics.jpg