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Name: Mellom
Status: Other
Grade: Other
Location: N/A
Country: N/A
Date: September 2005


Question:
Why is it not possible to obtain infinite magnification by using lenses with greater magnifying power?



Replies:
When the wavelength of the radiation used in the microscope (be it infrared, visible, ultraviolet, x-rays or even particle waves like electrons or neutrons) becomes the same order of magnitude as the sample (or the optical surfaces of the instrument) light begins to diffract, that is it scatters in directions other than the "line of sight" of the detecting radiation. This limits the distinctness of the boundaries of the object or the image being processed by the instrument. There are techniques -- too involved to address here -- where this limitation can be minimized, but it becomes an ongoing uphill battle. If you search the term: "microscope diffraction limits" on Google you will find both the cause of the classical limit as well as various techniques for extending the range of magnification and resolution of various instruments and techniques.

Vince Calder


Unfortunately, photons (light particles) do not move in a perfectly straight line. They oscillate along their line of movement. (kind of like a car swerving as it travels down the road) If you lined up enough lenses to be able to see at that scale, you would still not see your image, because all of the photons would be oscillating as they reach the lens. Only as the magnification is further reduced can the image become clearer, since whatever you are looking at is now many times the size of a photon's oscillation.

There are other microscopes, however, that do not use light to view very small items. An electron microscope uses a stream of electrons, and can 'see' right down to an atomic scale.

Ryan Belscamper



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