Counting Atoms

I tuned up my system for an hour or so, but I don’t know what the next step is and Chad isn’t around.  I have a busy day today so I’m going to check out now and come back to do some more work mid-week.

Firstly, I cleaned the input with compressed air and it didn’t help. Then I used a small wire around which I rotated a cleaning tissue. Then I push out the wire so that I made a small tube from the cleaning tissue and I tried to clean the input with that tube. This also wasn’t successful so I am afraid that we have send the meter to service.

I adjusted the vertical tilt on the grating to get a smooth single mode absorption dip on the oscilloscope (I at least I think it’s smooth).  Then I tuned the mirror system to get the beam to go through the whole system (AOM included) and into the optical fiber coupler at the other end.

I will not be able to come in tomorrow.

I cleaned the optical fiber outputs and input to the wavelength meter with lens cleaning tissues and methanol. The wavelength meter still can’t read the wavelength.  On the other hand, cleaning of the input was pretty hard. I tried my best but I am not 100% sure I removed all the dirt, if there was any. According to me, the problem is probably somewhere else..

Afternoon, I luckily found John and we adjusted the metal block so the beam can be oriented in the angle when all light is going throw the hole. I tweaked the whole system and I got maximum output both to krypton tube and to wavelength meter on fiber-couplers. What is strange, I can’t see the wavelength on meter despite the gain on on fiber-coupler was 200V on oscilloscope. It didn’t work even for Dave’s fiber, which I also tried to plug in.

Yesterday, I replaced the defective diode and started to set up a laser. I had to turn the lens inside, so the outgoing beam was parallel. After putting the laser into the metal box, I reached the limit of rotating the whole metal block inside the box and still, the part of a beam didn’go throw the hole in the box. I think I have to ask John to file away small part of copper block so that we can operate with laser beam angle more. Then, I can start to tweak all the laser paths to fiber couplers and Krypton tube and, possibly, to start finding the absorption wavelength.

10:30 - 1:15

I adjusted the laser to a wide range of temperatures, but did not find single mode absorption.  This means I will have to adjust the vertical tilt on the grating next time.

When I was setting up the experiment and tuning the outputs, I touched the button on the electric source of the laser diode. I got a shock of static energy (as I always get from optic tables) from the box of the source and from that point, the laser was producing very negligile output. I tried restarting and even changing the laser treshold by adjusting a grating but it was not succesful. Now, I can see only tiny and dim red spot on IR detetcotr evem for maximum current.

I scanned throw some adjustments of diffraction grating. I was very near the absorption but I couldn’t reach the stable state.

10:30AM - 1:00PM

I think I found it!  Wavelength ~811.52.