12 posts

I record a speckle pattern using off axis digital holography. However if I take consecutive shots with nothing being changed, I see that the correlation of the Hologram intensity reduces with that of the first shot. Due to which my reconstruction gives different recobstructed field at different times. My laser is stable. I dont see the speckle pattern changing visually in the camera. However the noise seems degrading my signal. Can you please help me with it.

Is the transmission matrix of a scattering medium a unitary matrix ?

Thanks Sebastin.

I would like to see how close the two speckle images are.

So by correlation you mean correlation coefficient if I am not mistaken ?

How can I measure the error between two speckle intensities. ?

Thanks Sebastien.

I succeeded in making a transmission matrix by
and performing SVD and normalization.

However I am interested in modeling a scattering medium which is combination of two operator first operator is a Random phase scattering matrix followed by a free space propagation. This is one layer and there are N such layers. Can you suggest me how can I do it in Matlab ?

I am a beginner in Matlab. I would like to simulate a transmission matrix in matlab. Can I get some papers/resources from which I can simulate it from the perspective of Matlab. Could anyone please help me.

Due you mean to say that it works ?

Did you make sure that the Laser is polarized in the working polarizing direction of the SLM ?


I am trying to project a random phase mask in which each pixel varies from 0-2pi.

I am using a phase only SLM. I understand that the if we need to get a phase pattern we need to use gerchberg saxton algorithm and back calculate that phase that would produce that, then match it with the gray levels of the SLM and inject the pattern on it. By pacing lens at f of the lens we get the required pattern.

But my question is what if Image SLM on to the sample. Will I get the same phase pattern

Thanks Sebastin.

I get it now. But will it be suitable to do both amplitude and phase modulation using the same setup ?

Is it possible to do amplitude modulation in phase only SLM?


Hi I am using a HoloEye Phase only SLM. I would like to illuminate my scattering medium using a line illumination.

For which I made a collimated laser beam. Then used a cylindrical lens to get line illumination on the SLM. Out of 1920x1080 pixels I want the phase variation only in the 960th column. For I which I created a phase mask with only enteries in the 960th column and loaded ito to the SLM. And this is the illumination that I want on my scattering medium. Unfortuately I get the light reflected from the SLM completely. How can I make sure that SLM reflects only the line I loaded?

Please can you help me