Nomarski Differential Interference Contrast
adapted to a
Bausch & Lomb Research (I) metallograph
by George Langford
When my consulting company (Amenex Associates, Inc.) had commercial laboratory space, we used a really nice Reichert MeF2 metallograph that had a Nomarski differential interference contrast accessory as well as a cute little microhardness testing device.  After the Enron debacle, it became uneconomical to keep the lab open, and I had to give up the Reichert metallograph for lack of space.  However, I was able to assemble a working Bausch & Lomb Research (I) metallograph from pieces obtained on eBay (but without the extravagant optical bench) and I've wanted to work out a way of fitting Nomarski DIC to that instrument.  Here's my prrevious progress, as of January 21, 2007.

The Bausch & Lomb Research (I) metallograph has polarized light as standard because it uses a Foster prism as the vertical illuminator.  In order to defeat the polarized light, one has to place a quarter-wave plate in the optical path (the "B" setting of the illuminator).  Therefore, there is no way to change the polarized light except to turn it on (crossed to extinction) or off (quarter wave plate).  There is no in-between setting.  That appears to present no handicap to the use of Nomarski differential interference contrast in my Bausch & Lomb Research (I) metallograph.  Bausch & Lomb later made available a complex accessory for providing the intermediate settings.

My previous setup had a serious error: I was putting the Nomarski wedge in upside down !  Once I realized that, progress came more quickly, and the images the setup produces became dramatically better and more useful.  That required I make some adapters: