Goldstone Scientific Blog

Prizmatix Fiber Optic Rotary Joint; Compatibility of with Lasers or other light sources

Posted by

Prizmatix fiber optic rotary joint with a Y-shaped fiber for bilateral stimulation

The Prizmatix Fiber Optic Rotary Joint is an important part of the Prizmatix  In-Vivo Optognetics Toolbox. It’s extremely low torque (<10μNm) allows even the smallest animals to move freely and its high transmission is helpful in getting as much power as possible to the target.

One really nice feature of the Prizmatix fiber optic rotary joint is that it can be used with a  Y-shaped Dual Fiber for bilateral stimulation.

We get a lot of inquiries from people who use lasers or other light sources that want to know if they can use our rotary joint.

The short answer is yes, when configured correctly and not for bilateral stimulation.

Here’s why:
Our rotary joint was design for LEDs with large emitters, like the Prizmatix Optogenetics-LED. Since our LEDs have a large emitter we can use a large core fiber from the LED to the rotary joint, and then at the joint step down to a single or Y shaped fiber with a smaller core. Since the first fiber is larger than the fiber or fibers on the spinning side of the rotary joint, there is very little rotational variation due to misalignment. See the “Additional Information” section on the Prizmatix product page.

So if there is a smaller fiber on one side and a larger fiber on the other, the rotary joint can successfully be used. With lasers, this can be done when the fibers are reversed, and a smaller fiber can feed a larger fiber.

One customer tested our rotary joint with her lasers. She used a 100um fiber on the static side, and a 200um fiber on the spinning side. She reported that “Rotation variation is very low (<=5%) when I used 100 um fiber. The transmission efficiency is also higher than the other brand I compared.”

A bilateral fiber, however, has to be fed by a fiber that is at least as large as the two fibers side-by-side. That is not possible with most lasers or other brands of LED.

Feel free to contact me if you have any questions about your setup.