- #1
Nickyvl
- 4
- 1
Dear fellow Physicists,
For my project I wanted to measure the thickness of a glass plate with white light interference. Before being able to measure, I had to setup an interferometer. Unlike with a Laser, with white light it is hard to find the interference pattern since the coherence length is only a micrometer. Finally, after setting up the interferometer I was able to look for the interference pattern but unfortunately it was not what was expected. Attached are two pictures of the interference pattern that was found.
For this interferometer a white light source with fiber, A 10mm N-BK7 Beam splitter and two round silver mirrors were used.
The pictures show that the interference pattern is only visible around the white light spot, instead of the spot being part of the interference pattern. Now, my quetion is, why is the interference pattern so weak compared to the spot? And why are these four extinctions visible (marked in the edited picture). May it be because of bad alignment? Or is there any other cause?
Hopefully someone is able to help me.Nicky
For my project I wanted to measure the thickness of a glass plate with white light interference. Before being able to measure, I had to setup an interferometer. Unlike with a Laser, with white light it is hard to find the interference pattern since the coherence length is only a micrometer. Finally, after setting up the interferometer I was able to look for the interference pattern but unfortunately it was not what was expected. Attached are two pictures of the interference pattern that was found.
For this interferometer a white light source with fiber, A 10mm N-BK7 Beam splitter and two round silver mirrors were used.
The pictures show that the interference pattern is only visible around the white light spot, instead of the spot being part of the interference pattern. Now, my quetion is, why is the interference pattern so weak compared to the spot? And why are these four extinctions visible (marked in the edited picture). May it be because of bad alignment? Or is there any other cause?
Hopefully someone is able to help me.Nicky