Day 4

After this morning's staff meeting, I reviewed the ALIO systems manual and practiced programming with Python until we met up with Dmitry for our last lesson of background in optics. We missed Peter today because he was out sick, but hopefully he'll be back with us tomorrow. We learned about image saturation, binary (16 bit in particular), digital to analog converters, and how HDR imaging was invented. Dmitry and I then set up our regulators for the pressurized nitrogen tank; the first one fit, but it had a leak; the second one we found wasn't strong enough to take the pressure from the tank, and the third one was strong enough, but with the wrong nozzle shape, so we had to remove it (with the help of vice-grips and WD40). We will be using the nitrogen gas to reduce some of the load on the motor by feeding the gas through two regulators to generate an input of about 30 psi to create a slight upwards pressure to help the small motor function more easily.

We then took a lunch break, after which I spent about an hour learning more coding techniques in Python. Then we returned to the lab to begin setting up our lab space for the experiment. With much rearranging of power cables and various setups, and several trips between labs to locate various materials, we made good progress on our setup. We connected our monitor and computer tower, as well as our power supply, and we set up our laser, which sends light through a fiber-optic cable to our "lamp", a ball of stable gas, which is heated to generate all wavelengths of light, which are sent through another fiber-optic cable to our monochromator, which we can use to create any wavelength of light we need.

We collected the light on the other side of the monochromator and sent it through another, smaller fiber-optic cable, which we sent through a collimator and a microlens to focus the light into one point. When we looked at the response from the camera when placed in front of the lens, the result was extraordinarily out of focus and much too large for our purposes, with an odd halo appearing around it, but by adjusting the position of the light source (manually) and the camera itself (using the computer and an actuator), we were eventually able to bring the size of the point of light down to a spot roughly 2 by 2 pixels, so approximately 3 microns by 3 microns, and much clearer. This would be an acceptable size for the purposes of our project, which we were very glad to achieve just by doing our initial tests, but we know that we can create a smaller, more uniform beam, so that is our next goal.