Phase contrast, whats the deal?
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- GreenLarry
- Posts: 360
- Joined: Sat May 07, 2005 8:54 am
- Location: North East of England
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Phase contrast, whats the deal?
I know a bit about microscopy, and have made my own dark field stop for my student scope, but what exactly is phase contrast, and what is its purpose? Is polarization involved as I see lots of colours.
Hi Larry, and welcome to the group!
Basically, phase contrast is a microscopy contrast enhancement technique that allows visualizing transparent objects, e.g. live cells. Various objects can retard (delay) light wave in a different way, and phase contrast technique helps to visualize this difference. The technique was invented in 1930s by a Dutch scientist Frits Zernike, who later was awarded a Nobel Prize for this discovery.
It is a bit more complicated than dark field microscopy. Two elements are required: a phase stop (annulus) in a substage condenser, and a specialized phase objective that includes a phase ring at a back focal plane.
My explanation is far from being clear, so you may wish to read a great description of phase contrast technique on Molecular Expressions website: Phase Contrast Microscopy.
One of our group members, Graham, has made a phase contrast setup by himself. He has got pretty impressive results. Check out his website: A very big small world.
Basically, phase contrast is a microscopy contrast enhancement technique that allows visualizing transparent objects, e.g. live cells. Various objects can retard (delay) light wave in a different way, and phase contrast technique helps to visualize this difference. The technique was invented in 1930s by a Dutch scientist Frits Zernike, who later was awarded a Nobel Prize for this discovery.
It is a bit more complicated than dark field microscopy. Two elements are required: a phase stop (annulus) in a substage condenser, and a specialized phase objective that includes a phase ring at a back focal plane.
My explanation is far from being clear, so you may wish to read a great description of phase contrast technique on Molecular Expressions website: Phase Contrast Microscopy.
One of our group members, Graham, has made a phase contrast setup by himself. He has got pretty impressive results. Check out his website: A very big small world.
Piotr
- GreenLarry
- Posts: 360
- Joined: Sat May 07, 2005 8:54 am
- Location: North East of England
- Contact: