2 Photoactivated atomic force microscopy with 2nd harmonic response

摘要

The present invention relates to an ultra-high resolution photoactive atomic force microscope using secondary harmonics. The photoactive atomic microscope includes: a photoactive light providing unit for focusing and providing a pulse laser beam of a preset reference frequency to a predetermined position of the objective to thermally expand a sample; A cantilever having a cantilever tip mounted on a distal end thereof; A signal detector for detecting and providing a signal corresponding to a position of the cantilever tip that changes according to the vibration of the cantilever tip; A lock-in amplifier module configured to detect and output a first harmonic signal and a second harmonic signal from the signals provided from the signal detector; An image signal processor configured to generate a first ultra-high resolution image and a second ultra-high resolution image of the sample by using the first harmonic signal and the second harmonic signal provided from the lock-in amplifier module; And a microscope controller for controlling the movement of the cantilever and the transfer stage. Is provided, and the cantilever tip is configured to contact the surface of the sample under the control of the microscope controller, by detecting the movement of the cantilever tip according to the thermoelastic expansion of the sample to detect the optical characteristics of the sample. The second ultra-high resolution image using the second harmonic signal has a better signal contrast than the first ultra-resolution image according to the first harmonic signal, thereby improving the resolution.