What makes a microscope?#
Optics#
Microscope is a tool that magnifies small things to appear large by creating a virtual image that is much larger than the original object (sample).
Modern microscopes are built with infinity-corrected microscopy objectives that create final image on the sensor. It is easy to understand such system using two-lens approximation
In modern microscopes the first lens can be called “objective” and second one “tube lens”. Together these lenses create magnified image away from the sample plane. Magnification comes from having lenses of different focal length, otherwise the system is a “relay system” that doesn’t create magnification. Single lens can be used as a magnifying glass for human observer because second lens in that system is human eye (focal length approx. 17mm).
Hardware#
Main components of a microscope is:
optical elements that create and magnify image of the sample, focus light, and correct for any imperfections in our ability to make lenses
system to focus the optics on parts of the sample (XYZ stage)
digital readout system that allows capturing light and converting to electrical signals that are recorded as “image pixel intensity”
computer to store and process digital data from sensor
Full-stack microscopy aims to cover topics from all these areas, plus help with understanding what produces the image in the first place and how light interacts with biological samples