Unfortunately I have lost quite a bunch of mail today. I could
not find the reason. Is there any mail eating virus around?
Beacuse it has happened when I was reading
your mail, I could not finish to read it. I remember only that you are
discussing direction difference of o and e ray. I would like to mention one
possible origin of the results.
When the both surfaces of the specimen are not exactly parallel, the prism
effect occur. The ordinary and the extraordinary rays are not parallel
anymore after extinction. Since differences of refraction indeces are about
100 times larger as the difference between
blue and red light refraction index in a glass prism, also the wedge with an
angle of only 1 degree can split the rays i.e. they have different direction
in the space. The method for measuring LC inedeces was presented in AJP
62,19994 p.858. This method we use to measure both indeces for a liquid
crystal as a demonstration experiment and as laboratory excercises for
students. The cell consists from two glases and is approximately 1cm long.
The LC is filled into the cell. On one side the glasses are glued together,
on the other side they are 200 mum apart. The laser spots, when laser light
passes the sample are about 10cm apart, when the screen is in 5 meter
distance.
I have published the thing in a local paper for teaching physics.
Unfortunately is in Slovene but if you are interested I can send you the
copy, at least pictures are there.
Regards
Mojca
Dr. Mojca Čepič or Dr. Mojca
Čepič
Jožef Stefan Institute Faculty
of Education
Jamova 39
Kardeljeva pl. 16
1000 Ljubljana 1000
Ljubljana
Slovenia
Slovenia
e-mail: mojca.cepic@ijs.si
tel.: +386 61 17 73 471 +386 61 18
92 200
fax.: +386 61 17 73 716 +386 61 18
92 233