Re: DIC - PDF now available!
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Dear listers
A PDF is now available, thanks to a suggestion from Shalin Mehta. It is not elegant, but it is readable and very usable. If you would like a copy, please contact me directly, off-line. Best regards, Barbara Foster, President We've moved! Microscopy/Microscopy Education 7101 Royal Glen Trail, Suite A McKinney TX 75070 P: (972)924-5310 Skype: fostermme W: www.MicroscopyEducation.com MME is now scheduling customized, on-site courses through December. Call us today for details. P. S. Need a good general reference or light microscopy text for next semester? Call us today to learn more about "Optimizing LIght Microscopy". Copies still available through MME... even for class-room lots ... and we give quantity discounts. Just call us here in the MME office for details. Dear Sarah, I wrote an article in the April 1988 issue of American Lab on the details and fine tuning of DIC. Unfortunately, it is not available electronically. I can send you a Xerox copy if you send me your contact information. There is also a discussion in Optimizing Light MIcroscopy, available through our website, www.MicroscopyEducation.com. An important point to keep in mind is that DIC uses a sheared beam of polarized light to create what is essentially a reference beam and a sample beam. The reason that you do not see a ghost image is that the shear is smaller than the resolving power of the microscope ("differential"). Since the polarizers are on either side of the sample, materials that responde to polarized light (ex: plastic slides, coverslips, growth chambers) will respond to the POL component, giving misleading results. To avoid this pitfall, I've developed the following set-up procedure overt he years: 1. Establish Koehler illumination without the polarizers or beam splitters in place. Observe any nature color. 2. Insert the polarizer and analyzer and cross them. The background should be black. Observe any bright objects. These are the ones that will respond to the Pol components of the system, not the DIC. At this point, it is also really helpful to have a rotating stage since sample orientation can mask lack of response. 3. Insert the beam splitters. (Since the shear depends on the NA, these need to match - both each other and the NA of the objective/condenser set). 4. For optimum contrast, tune the compensator so that the background is soft dove gray. One slope should then be bright and the other dark. Since the beam splitters induce a shear direction, objects that have specific orientation (ex: fibers, long scratches, etc.), orient the structures so that the long direction is perpendicular to the shear direction. This is also a clever trick that can also be used to make disruptive features disappear. Again, a rotating stage is really helpful. Hope this is helpful, Barbara Barbara Foster, President We've moved! Microscopy/Microscopy Education 7101 Royal Glen Trail, Suite A McKinney TX 75070 P: (972)924-5310 Skype: fostermme W: www.MicroscopyEducation.com MME is now scheduling customized, on-site courses through December. Call us today for details. P. S. Need a good general reference or light microscopy text for next semester? Call us today to learn more about "Optimizing LIght Microscopy". Copies still available through MME... even for class-room lots ... and we give quantity discounts. Email Ken Piel here in the MME office for details ([hidden email]). At 11:29 AM 9/26/2007, Dale Callaham wrote: Search the CONFOCAL archive at |
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