Atomic force microscopy capable of vibration isolation with low-stiffness Z-axis actuation

Area of Science:

• Materials Science
• Nanotechnology
• Mechanical Engineering

Background:

• Traditional atomic force microscopes (AFMs) often require bulky external vibration isolation systems.
• Achieving high-resolution imaging necessitates minimizing probe disturbances from environmental vibrations.

Purpose of the Study:

• To develop an AFM with integrated vibration isolation capabilities.
• To enable high-resolution AFM imaging in environments with significant vibrations without external isolation.

Main Methods:

• Utilized internal Z-axis Lorentz actuators for probe actuation and vibration isolation.
• Designed low-stiffness flexures for large Z-axis travel (>700 µm) and mechanical isolation.
• Implemented closed-loop feedback control using a displacement sensor for probe-sample tracking.
• Combined feedforward control with a vibration sensor for enhanced vibration rejection.

Main Results:

• Achieved a closed-loop control bandwidth 35 times higher than the first mechanical resonant frequency.
• Demonstrated robustness against flexure nonlinearity and utilized resonance for improved sample tracking.
• Successfully rejected 98.4% of vibrations by activating the integrated control systems.
• Enabled successful AFM imaging within a highly vibrational environment.

Conclusions:

• The developed AFM system effectively isolates the probe from vibrations using internal actuators and advanced control strategies.
• This integrated approach allows for high-resolution imaging in previously challenging environments.
• The system offers a more compact and potentially more versatile solution for AFM applications.