Undergrad Optical Tweezer Laser Focus/Alignment Troubleshooting

Thread starter wheatie
Start date Apr 9, 2024
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Optical tweezers

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The discussion revolves around troubleshooting an optical tweezer setup that includes a beam expander and a dichroic mirror, with a focus on confirming laser trapping of particles. Users are uncertain if the laser is effectively trapping particles within the camera's field of view. Key questions include methods to verify the laser's focus and how to ensure that both the camera and laser are aligned at the same focal point. The participants seek practical solutions to determine the effectiveness of their optical setup. Effective troubleshooting is essential for advancing their research in optical tweezers.

Apr 9, 2024

wheatie

TL;DR: Optical Tweezer Trapping Help

Currently we have an optical tweezer setup that has a beam expander + dichroic mirror that fills the aperture of the objective, and a microscope that is able to look into the aperture and see a diameter of about 30 microns.
We have been stuck for a couple weeks now, as we do not know if our laser is actually trapping any particle/if the trapping is occurring within the fov of the camera.
Our questions would be:
How can we tell if our laser is focused.
How can we tell if our camera and laser is focused at the same point.

I've included a photo of our current setup.
Thank you!