Holographyforum.org / holowiki.org

A way to measure the beam profile and paramaters would be good to tell the difference using standard spatial filters Vs these other more exotic lens designs as the eye only goes so far but this sounds interesting.

I'm finding a few references to GRIN lenses in holography, and bought one for testing:

http://www.ebay.com/itm/NEWPORT-OPTICS-LGI830-6-GRADIENT-INDEX-MICRO-LENS-GRIN-Plano-Plano-46-NA-/261746600571?

Also noticed a patent:

https://www.google.com/patents/US20070109555

And something on the Integraf site:

"[b]External Hologram Recording Endoscope[/b]
In the external hologram recording endoscope, a conventional endoscope is used. The system records the hologram outside the endoscope using an external reference beam. An endoscope with extremely small outer diameter can be used but this results in a loss of parallax and a small entrance pupil which produces speckles in the reconstructed image. However image plane holograms can be recorded to reconstruct the image without speckles. In order to obtain a high signal-to-noise ratio, the holographic endoscope must use gradient-index (GRIN) rod lenses. The speckle noise is reduced by illuminating and imaging the object by the same GRIN lens. An electro-optic crystal can be used as the photographic storage device in the holographic endoscope to provide in-situ recording, reconstruction, and erasure. These will make a new class of medical instruments for use not only in medical diagnostics but also in industrial testing." http://www.integraf.com/a-holography_medical_applications.htm#ixzz3PlAZdZX4

I'm wondering how clean (or dirty) the direct output from the GRIN lens will be. Also bought a Thorlabs aspheric lens from the same eBay seller.

Have a look at:

http://www.nxtbook.com/nxtbooks/newportcorp/resource2011/#/762

Joe

Do you mean just an optical fiber?
By the way, I did not :)

Just checking:

Has anyone used a GRIN lens for beam expansion, either reference or object?

Thanks