Possible to make speckles without a Laser?

[darthw]

Hello,
it is possibile to make speckles on a surface with a LED or something else? With a Michelson Interferometer you can get interferences with an LED -> are this already speckles?

regards,
Hans

 

[phinds]

what do you mean by "speckles" ? Do you mean just colors on the surface or do you mean pits in the surface ?

 

[darthw]

Hello,
I mean the second one, this pits in the surface

 

[Ibix]

You get speckle when coherent light hits a diffuse reflecting surface. Can you think of a way to get coherent light from an LED?

 

[darthw]

right now, no...I don´t know how to realize this

 

[Andy Resnick]

Hello,
it is possibile to make speckles on a surface with a LED or something else? With a Michelson Interferometer you can get interferences with an LED -> are this already speckles?

regards,
Hans

Sure- since speckle is a measure of spatial coherence, you can create speckles with any source. You can image speckle generated by sunlight: the speckles are about 0.06 mm in diameter and you need to spectrally filter the light to get good contrast.

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-37-17-3516

 

[darthw]

Hello,

that sounds great. I´m trying to build up this experiment.
thx