This special issue of Microscopy Today is devoted to light microscopy. Light microscopy is microscopy that employs light as a medium, or so I thought. Every week I see “optical microscopy” used as a synonym for light microscopy. I cannot understand the popularity of this confusing term. For people outside our field, the term “optical microscopy” must be perplexing: does it mean electron optical or light optical? My point is that we should present the techniques we use in clear unambiguous language: light microscopy, electron microscopy, scanned probe microscopy, etc. Regardless of logic, there are still strong adherents to the term “optical microscopy.”
Many reasons are given for the use of the term “optical microscopy.” Certainly “optical” makes one think of techniques other than scanned probe microscopies. Some people relate their use of “optical microscopy” to the connection with glass lenses or to the dictionary definition for “optical”: using the properties of light to aid vision. Others say that “optical” was directly related to photons before electron microcopy was invented and thus has priority.
Proponents of replacing “optical microscopy” with “light microscopy” note that physicists sometimes call the synchrotron a light source because it generates photons over a range of wavelengths. Others state that lenses and optical equations are also used to focus electrons and ions. Of course, when describing lenses for electrons, an additional modifier is used: “electron optics.” It is easy to see why some people avoid these fine distinctions and use “light optical microscopy” or LOM.
The tendency to use one term or the other may be industry- or discipline-related. Microscopists who only use light microscopy and never deal with images or maps produced by other means may have a tendency to call the technique “optical microscopy.” However, most research in the life sciences and physical sciences requires a wide range of complementary microscopy techniques. The photonics industry often, and perhaps justifiably, skips the adjective altogether and calls all work with a microscope “microscopy.” Another confusing term is “digital microscopy” that also tends to mean light microscopy, even though all microscopies now use digital technology.
One of the goals of this magazine is to make all types of microscopy and microanalysis accessible to every microscopist. To do this requires that logical terms be used to identify microscopy techniques. Another goal is to present microscopy methods to non-microscopists outside our community in a way that makes our field understandable. Thus, I vote for promoting the term “light microscopy” to refer to all magnified images made with visible, IR, or UV light.
