Type: Process Essays
Sample donated: Franklin Dunn
Last updated: September 23, 2019
Optical Microscopy:Inoptical microscopy the light is used as the main source for imaging process. Itis very simple to use.
It is not used under vacuum unlike electron microscopes.Major advantage of the optical microscopy is that we can image living cells. Itis low cost technology. The limitation of this microscope is that theresolution is limited by wavelength of light. Scanning electron Microscopy (SEM):Ithas great depth of field when compared to optical microscope. We can produce 3Dimage of the specimen using SEM. Sample preparation is easy for SEM.
The secondaryelectrons are responsible for the image formation. Higher resolution thanoptical microscope. Higher magnification. Transmission Electron microscope (TEM):TEMgives high resolution image of the internal structure of specimen. We can tiltthe sample and take measurements. Transmitted electrons are responsible for theimage formation.
It has higher magnification and we could observe the structurethat cannot be seen in optical microscope. Helium ion microscopy (HIM):InHelium ion microscopy, the ion source is helium ions or neon gas. Interactionvolume is lower when compared to SEM.
Milling can be done at faster rate.Higher depth of focus. HIM gives better resolution than TEM. Unlike SEM, nonconductive samples can be imaged using Helium ion microscopy. Atomic Force Microscopy (AFM):Theelectron microscopes needed vacuum environment but atomic force microscopy canworks in air ambience. Surface topography can be determined using physicalcontact. It does not needed special coatings on the sample for imaging process.
Scanning Near Field Optical Microscopy(SNOM):Thescanning near field optical microscopy has large spatial resolving power. Wecan measure the surface topographical information without physical contactunlike AFM. Inner structure of the specimen can be analyzed using SNOM whichatomic force microscopy cannot do.