Microscopy

What is Microscopy?

Microscopy is the fancy term used to describe viewing things through a microscope you wouldn’t otherwise see. There are many different variations of the technology. There are three well known branches: electron, optical, and scanning probe microscopy. In recent years a fourth field - X-ray microscopy - has begun to gain popularity, but we’re not going to be focusing on that.

Early forms of microscope are the magnifying glass of the 17th century and the eyeglass of the 13th century. One of the earliest practitioners was Galileo Galilei in 1610 and Antonie van Leeuwenhoek who build the first “modern” microscope and is hailed as the first microscopist and microbiologist.

Optical Microscopy

Optical or light microscopy is the most used. It’s the relatively simple process of looking at something through a lens or several lenses used to magnify the object. Visible light is transmitted through or reflected off the object and sent through lenses. The resulting image can be seen with the naked eye or captured digitally. Optical microscopes are probably the ones you see in schools.

Electron Microscopy

An electron microscope is used for extremely tiny objects. They use an electron beam to map out an image of the object.

Two kinds of electron microscopy are known: transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

TEM is a technique in which electrons are transmitted through a specimen (usually ultra-thin). An image is created through the interaction of the electrons with the subject material. Transmission electron microscopes are capable of imaging at a significantly higher resolution than light microscopes, owing to the smaller de Broglie wavelength of electrons. This enables the instrument to capture fine detail—even as small as a single column of atoms, which is thousands of times smaller than a resolvable object seen in a light microscope.

A scanning electron microscope is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample, producing various signals that contain information about the surface texture and composition of the sample.

Scanning Probe Microscopy

A scanning probe microscope uses the tip of a probe to scan the surface of the subject matter. It was developed to be able to take a closer look at “flat” surfaces and discover the textural composition of the object. There are three different kinds. There is the atomic force microscope, the scanning tunneling microscope, the photonic force microscope and the recurrence tracking microscope, and the ultrasound microscope.

What type of microscope works best?

There is no “best” microscope. It all depends on what you are trying to see or measure. It’s important to know what you are going to be looking at so you can select the right tool.