Interference Patterns Between Two Petrographic Slides

Here you can discuss sample and specimen preparation issues.
Post Reply
Message
Author
microb
Posts: 729
Joined: Wed Mar 27, 2019 6:39 am

Interference Patterns Between Two Petrographic Slides

#1 Post by microb » Thu Apr 01, 2021 5:34 am

Don’t know what to do with this, but sliding two microscope slides together shows interference patterns between the glass at the right angles of light.

I washed them with alcohol so I don’t think it’s an oil layer.
Attachments
IMG_5582_1K.JPG
IMG_5582_1K.JPG (33.47 KiB) Viewed 2064 times

PeteM
Posts: 2986
Joined: Tue Dec 06, 2016 6:22 am
Location: N. California

Re: Interference Patterns Between Two Petrographic Slides

#2 Post by PeteM » Thu Apr 01, 2021 6:33 am

Most likely a similar effect to optical flats.

In metrology, they are used with monochromatic light sources to determine flatness of surfaces to microns. With full spectrum sources, you get the colors.

MichaelG.
Posts: 3976
Joined: Mon Apr 10, 2017 8:24 am
Location: North Wales

Re: Interference Patterns Between Two Petrographic Slides

#3 Post by MichaelG. » Thu Apr 01, 2021 7:23 am

.

As PeteM says ^^^

For a brief introduction; this video is worth a look : https://youtu.be/xSYl7q6yKPU

MichaelG.
Too many 'projects'

microb
Posts: 729
Joined: Wed Mar 27, 2019 6:39 am

Re: Interference Patterns Between Two Petrographic Slides

#4 Post by microb » Thu Apr 01, 2021 1:08 pm

Thorlabs uses this technique to mount optics for lapping:

https://www.youtube.com/watch?v=se3K_MWR488

microb
Posts: 729
Joined: Wed Mar 27, 2019 6:39 am

Re: Interference Patterns Between Two Petrographic Slides

#5 Post by microb » Thu Apr 01, 2021 1:13 pm

PeteM wrote:
Thu Apr 01, 2021 6:33 am
Most likely a similar effect to optical flats.

In metrology, they are used with monochromatic light sources to determine flatness of surfaces to microns. With full spectrum sources, you get the colors.
Here's an optical flats test I did, checking some optical flats on a first surface mirror (aluminum on glass, metal side touching the optical flat). I remember thinking that I thought the fringing would be stronger. This uses a laser in a ping pong ball:
Attachments
IMG_4484_cropped_1K.jpg
IMG_4484_cropped_1K.jpg (91.24 KiB) Viewed 2024 times

User avatar
Rossf
Posts: 363
Joined: Mon Jan 20, 2020 12:39 am
Location: Victoria Australia

Re: Interference Patterns Between Two Petrographic Slides

#6 Post by Rossf » Sat Apr 03, 2021 12:36 pm

My slides look like that also-reminds me of soap bubbles...

Post Reply