http://panda.unm.edu/courses/finley/P262/CircPolar2/CircPolar2.html If you can get a quarter wave plate you can create diffrent ammounts of ellipitality by varying the fast axis of the plate with the polarization axis on a linear polarizer, 45deg creates circularly polarized light (well depending on the freq it will vary in ellipicality).
On Wed, 20 Aug 2003, Dr E D F Williams wrote: > Date: Wed, 20 Aug 2003 10:22:50 +0300 > From: Dr E D F Williams <[EMAIL PROTECTED]> > Reply-To: [EMAIL PROTECTED] > To: [EMAIL PROTECTED] > Subject: Re: A test -- 'crossed nicols' > Resent-Date: Wed, 20 Aug 2003 03:23:04 -0400 > Resent-From: [EMAIL PROTECTED] > > That's just what I was trying to find out. Special polarizers for > microscopes cost and awful lot and I want to try a circular polarizer to see > if it will approximate the behaviour of a very expensive elliptical > polarizer. Lamda plates also cost at least one arm and leg and I'm thinking > about what I can do in that case as well. Even a simple 1/4 wave plate, once > available for the Zeiss range of instruments -- it went into the filter > holder under the condenser -- was expensive. > > Don > _______________ > Dr E D F Williams > http://personal.inet.fi/cool/don.williams > Author's Web Site and Photo Gallery > Updated: July 31, 2003 > > > ----- Original Message ----- > From: "Robert Szasz" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Wednesday, August 20, 2003 10:11 AM > Subject: Re: A test -- 'crossed nicols' > > > > From my knowledge of how a circular polarizer works you will get a 3db > > loss for every re linerazation (every polarization after the 1/4 wave > > plate). Two circular polarizers (any positions)therfore would cut the > > amount of light recieved in half (assuming perfect rejection of the > > perpendicular polarization). If you place a linear polarizer in front of a > > circular polarizer it will act just like two linear polarizers, but the > > light after the 1/4 wave plate in the circular polarizer will be > > circularly polarized (either right or left handed depending on the way > > the polarizer was constructed)) > > > > On Wed, 20 Aug 2003, Dr E D F Williams wrote: > > > > > Date: Wed, 20 Aug 2003 08:34:05 +0300 > > > From: Dr E D F Williams <[EMAIL PROTECTED]> > > > Reply-To: [EMAIL PROTECTED] > > > To: [EMAIL PROTECTED] > > > Subject: A test -- 'crossed nicols' > > > Resent-Date: Wed, 20 Aug 2003 01:34:17 -0400 > > > Resent-From: [EMAIL PROTECTED] > > > > > > If anyone has two circular polarizers I'd be grateful if you would > perform a > > > test. Put one over the other and rotate to see if the field becomes > > > completely dark when they are crossed. And ... if you also have an ordin > ary > > > polarizer try the same experiment using one normal and one circular > > > polarizer. > > > > > > Don > > > _______________ > > > Dr E D F Williams > > > http://personal.inet.fi/cool/don.williams > > > Author's Web Site and Photo Gallery > > > Updated: July 31, 2003 > > > > > > > > > > > > > > > > >
