I've created two fringe images - one of a laser diode that's able to make holograms which outputs 5mW.

The second laser outputs 20mW and so far I've not been able to make a hologram with it.

I had a look at how to make fringe patterns to check the coherence of the lasers, and this is what I finally came up with:

Two fringe images

Is it possible by comparing the two images to say that the 20mW laser should be able to make holograms, and I've just messed the picture up somehow?

I think if the coherence distance of the beam is low and bad for holograms, the fringes would be close together relative to a better hologram laser?

Any help would be much appreciated!


The fringes should be the same width if the the laser color is roughly the same. A wider-band laser would simply produce lower contrast fringes. I see pretty good contrast in both images, so either laser should produce a decent hologram. Could it be that you are over-exposing the film with the 20mW laser?

  • $\begingroup$ It's the litiholo auto-developing film, which stops the film from becoming over-exposed some how. I think my laser stand may be too unstable or the diode was still warming up... I'll try again with a firmer stand. $\endgroup$ – SarahC Jan 25 '17 at 12:54

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