Unwanted fringes

[Din]

Petr, you got your comment in just at the same time as I did! I think we both agree it's object motion

[Ed Wesly]

Here are more images of the resonances of guitars and other stringed instruments visualized by holographic interferometry, from the Rossing book (ISBN 0-201-15727-6)

Interfero1.jpg (261.99 KiB) Viewed 2807 times

Interfero2.jpg (306.37 KiB) Viewed 2807 times

Interfero3.jpg (198.89 KiB) Viewed 2807 times

As you can see there have been many successful guitar interferometry holograms made. The problem here is not just the guitar moving, but the reference surface, plus a white card in a lens mount along with the speaker have the fringes. Either the reference mirror or object illumination is moving, or more than likely it is a multimode laser. Only a new laser will tell.

Hope to see some good results!

[Ed Wesly]

Just checking to see if any progress has been made on this project. Looks like fun once you get over the laser!

[lobaz]

Just checking to see if any progress has been made on this project. Looks like fun once you get over the laser!

We are in touch with Peter and are planning my visit in their lab. Sure we will post the result.

[lobaz]

Confirmed. The laser was mode hopping. There were some minor problems in the setup as well (too much components, too long exposure time etc.), but the laser was the major one. With my Lasnova 50 mW (thanks, Phil!), everything worked fine.