Posted by
Stanislav Vitha-2 on
URL: http://confocal-microscopy-list.275.s1.nabble.com/reflected-light-profilometry-trrough-plastic-mystery-bands-tp7584686.html
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Hallo,
I have a little mystery.
I am trying to measure depth of a microchannel (empty, air filled) using
confocal microscopy in reflected mode.
The microchannel is created by sandwiching a ~20 um PET (Mylar) spacer
between two ~170 um thick Mylar sheets. The spacer has a thin layer of
cyanoacrylate glue on both the top and bottom side.
I am performing line-Z scan, with 0.25 um z-step, using a 20x/0.75 dry
objective.
I expected to get two reflections, one from the top of the channel, one
from the bottom of the channel, just like it worked on microchannels made
out of glass that I imaged previously.
However, I am getting additional reflections and am not sure why and also
do not know which one I should take as representing the bottom of the
channel.
See the image here:
http://i.imgur.com/Scj4i6y.jpgReractive index of mylar is about 1.5, but I do not think I need to correct
for z-axis compression since the channel is fille with air.
The reflections are at 20, 40, and 60 um from the first reflection (top of the
channel)
The lineZ-scan through the spacer shows two reflection peaks, nominally
~40um apart, after z-axis correction it is ~60 um. Even if this is true and
the spacer is really 60 um thick, I am still puzzled by the extra reflections
in the air channel.
Any hints/input is appreciated.
With regards,
Stan Vitha
Microcopy and Imaging Cneter
Texas A&M University