User:Pranav Rathi/Notebook/OT/2010/04/20/Super easy way to straighten and align two laser beams simultaneously

Super easy way to straighten and align any two laser beams (visible and IR) simultaneously on the top of each other

Introduction

YAHOO…..YA…BA…DA…DOOOOO……..Today I made a major breakthrough in Tweezers alignment: First I was able to align the HE-NE with IR, second I invented a super easy way (Two End Apertures Thread Alignment TEATA)with web cams, to do it. It is so easy that it is almost boring. Now we are able to align telescope, periscope mirrors, steer assembly and objective with HE-NE, while IR sitting right on the top.

Labview-program to assist laser alignment

I wrote a software in LabVIEW called Laser alignment 3D. This software can be used with any USB camera for onsite indirect or direct viewing of laser beams. The 3D graph help to align and overlap the two beams (in this case He-Ne and IR).

Set-Up

The set-up for TEATA is as follows: File:Video 1.wmv

The goal of the set-up is to straighten and align the beams in x (horizontal to the set-up plain) and y (direction normal to the plain) directions, overlapping each other. According to the set-up I used two apertures, a sewing thread and two web cams. First aperture and web cam is installed next to the upstream IR-mirror with an opening size of the beam, next aperture and web cam is downstream roughly 70cms away. The thread is running right through the two apertures. Both the apertures are mounted on the vertical-expendable posts.

Procedure

Following steps:

1. IR spot is seen on the first aperture (upstream aperture; next to the IR mirror), both the aperture and up-stream IR mirror are adjusted such the beam goes right through the first aperture.
2. Now the second aperture height and opening is corrected by putting it next to the first (this way both the apertures have same opening’s height). Next the second aperture is moved to the downstream with a thread going through it. Next it is moved in x direction such that the thread is aligned with the holes on the optical table (this is done by eye-balling the thread with holes on the optical table in the back ground). Once this is done, the second aperture is aligned in the x and y directions with the first.
3. Now the beam is adjusted through downstream IR mirror such; it makes its way to the second aperture. When the beam is seen on both apertures through the web cams: one by one upstream and downstream IR is tweaked to make beam go through both up and downstream apertures. Now the IR beam is straight in x and y direction.
4. Next red He-Ne beam is put through the IR mirror and aligned with IR beam following the same procedure in step 3. Now both the beams are straight and overlapped.
5. In the last step overlapping can be checked by blocking HE-NE on/off.

Pros and Cons

Pros: Easy to set-up and super fast. Beams can be seen on the computer monitor and adjusted with highest precision in no time.

Cons: Little hard to align the thread with optical table holes (working to develop easier and more accurate way to do this).He-Ne is too bright to see faint IR in the camera and on the card, so have to do one by one. High power IR will burn the thread.