Scanning probe microscope and method for detecting proximity of probes thereof

A scanning probe microscope having a first probe and a second probe both for scanning a sample while maintaining a constant distance to a surface of the sample, comprising:

• a) a first tuning-fork oscillator to which the first probe is attached;
• b) a second tuning-fork oscillator to which the second probe is attached;
• c) a scanner for moving each of the first probe and the second probe relative to the sample while resonating each of the first tuning-fork oscillator and the second tuning-fork oscillator;
• d) a vibrator for providing either the first probe or the second probe with a vibration of a specific frequency;
• e) a signal detector for detecting a voltage signal of the specific frequency induced in each of the tuning-fork oscillators when the first probe and the second probe are approximated to each other while the first tuning-fork oscillator and the second tuning-fork oscillator are resonated;
• and
• f) a probe proximity detector for detecting proximity of the first probe and the second probe to each other based on a voltage signal of the specific frequency induced in each of the first tuning-fork oscillator and the second tuning-fork oscillator.

A method for detecting proximity of probes of a scanning probe microscope having a first probe and a second probe both for scanning a sample while maintaining a constant distance to a surface of the sample, comprising the steps of:

• providing either the first probe or the second probe with a vibration of a specific frequency;
• monitoring the vibration of the specific frequency of the first probe and the second probe;
• and
• detecting proximity of the first probe and the second probe to each other based on a change of at least either a vibration of the specific frequency of the first probe or a vibration of the specific frequency of the second probe.

A method for detecting proximity of probes of a scanning probe microscope having a first probe and a second probe both for scanning a sample while maintaining a constant distance to a surface of the sample, wherein:

• the first probe is attached to a first tuning-fork oscillator;
• the second probe is attached to a second tuning-fork oscillator;
• a vibration of a specific frequency is provided to either the first probe or the second probe;
• and
• proximity of the first probe and the second probe to each other is detected based on a voltage signal of the specific frequency induced in each of the first tuning-fork oscillator and the second tuning-fork oscillator.