Optical Microscopes have their limitations and this limitation has to do more with the property of light than the technology of the microscope. On the other hand electron microscopes can be used for higher magnifications but the specimens have to be thin and non living. The answer to this dilemma is Atomic Force Microscopes which can help scientists peek further into the nano scale world. However it suffers from a very big downside. Before delving into the downside, let us see how an Atomic Force Microscope works.
The atomic force microscope (AFM) is a type of scanning probe microscopes (SPM). SPMs are made in such a way to measure local properties, such as height, friction, magnetism, with a probe. To obtain an image, the SPM raster scans its probe over an area of the sample and in the process measuring its local property.
The nanowire probe is moved over the surface of the specimen to be measured. The probe is incredibly thin and is 500 times thinner than the hair. Hence it is susceptible to vibrations which can cause interference in the accurate measurements.
The solution was perfect except for one problem-the microscopes probe could not be used when the laser was on, since the laser’s energy could overwhelm the sensitive measurement. The solution to this problem was to alternatively switch on and off the laser and make measurements when the laser is off before the nano probe reaches room temperature.
Repeating those measurements during a number of heating and subsequent cooling cycles can give an accurate final value.
Atomic Force microscopes have much higher resolutions, thousands of times greater than optical microscopes. They were invented in the 80’s by researchers at the IBM Research-Zurich, a feat which earned them the Nobel Prize in 1986