User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2009/06/27/1064 Optical tweezers
Today I came in thinking I could move the microscope myself. Dumb dumb dumb... At any rate, I fussed with the 1064 optical tweezers today and I had to make a modification to the setup. Before I modified the setup, I played around with the output power of the laser and looking at the optical axis I made yesterday to see if the beam would deviate with power. I didn't find any conclusive evidence that it did but I kept working with it above 1 W.
The modifications I made where as follows:
As you can see, I had to move the power modulator from yesterday. I had to do this because the entrance and exit pupils do not live on the same plane.
I didn't realize this at first. So, I wasted time trying to see what was going on. An hour wasted when I should have looked at the specs of the thing before I started fussing with it.
Grrr... Why do I keep teaching myself this lesson? Well, it was only an hour...
After realizing this, I decided that I wanted to maintain a nice optical axis so I opted to put the power modulator before the mirrors. I think the power modulator has built in ND filters but, I don't know what the OD of them are nor do I know how to use them. I'm guessing that they are controlled by the only knob on the thing.
After realignment, I put in the 10X Galilean Beam Expander. This guy is mounted on a XY stage pieced together from parts and a 2" kinematic mirror mount. This is so I have the ability to move the expander up and down, left and right, and pitch and yaw. Aligning the beast was a bit cumbersome but I did it. Here's what I did:
- Mount an iris on the expander entrance pupil.
- Close the iris so that I could only see the outer edge of the beam around the open iris with the infrared viewer.
- Adjust the X and Y position so that the beam is in the center of the iris.
- Open the iris and view with the camera the position of the beam. The camera was close to the expander and was centered.
- Move the camera away from the expander and see where the beam moved to.
- Adjust pitch and yaw.
- Close iris and see how changing pitch/yaw affected the XY position. Change accordingly.
I have no idea if this is the best way to do this, but in the end it worked. I just iterated the last steps until my beam did not deflect any with the expander in place.
- Move the microscope into the new lab.
- Setup the periscope.
- Add steering optics.
Koch question: Do we have another dichroic mirror for 1064 that will mount into the cage cube I designed?
- Steve Koch 23:55, 27 June 2009 (EDT): I think probably, but I'm not sure. You'll have to check with Larry. I thought we did.