Coupling Synchrotron Radiation into Fiber

[Johannes Steinmann]

Hi all,

in our booster we can't install a streak camera / beam line. So, we are thinking about coupling light from a view port into a fiber and transport it to the streak camera (~20m). Does someone have experience with coupling bending magnet radiation into a fiber? Which coupler to use, how to focus, which fiber, which frequency (range)?

I appreciate any suggestions.

Thanks,
Johannes

[Kees Scheidt]

Hi Johannes,
I read and understand your problem, and I think your approach of using a fiber to get the light from the tunnel
to your lab is feasible, but I have no direct experience with it. Stay in touch, and share your future experience,
it is certainly relevant.

[Ji-Gwang Hwang]

 Dear Johannes

Our group had the idea to couple SR light into an optical fiber to convey the light to a fast photodiode (with an active area of 200 um^2) and we tried a proof-of-principle using a liquid light guide (something like: https://www.edmundoptics.com/f/liquid-light-guides/11425) at an optical table with SR since the liquid cable has a large inlet aperture, high transmission, and a large numerical aperture (for easy coupling).

In the test, the transmission was okay and input coupling was easy since that light guide has a large aperture.
But it is difficult to get proper outcoupling optics for the small active area. Due to the large NA, the light is quickly diverse and then it demands a lens close to the output port of the light guide. But this leads to a small magnification that causes the loss of a lot of light intensity. I guess this is the same issue for the streak camera.

 Best regards

Ji-Gwang Hwang

[Johannes Steinmann]

Dear Kees and Ji-Gwang,

thanks much for your comments.

[...] we tried a proof-of-principle using a liquid light guide (something like: https://www.edmundoptics.com/f/liquid-light-guides/11425) at an optical table with SR since the liquid cable has a large inlet aperture, high transmission, and a large numerical aperture (for easy coupling).

This is an option we did not think about. Thanks!
We will not be able to avoid setting up a test setup in the lab. If we find something useful you will hear about it ;-)

Cheers,
Johannes