Diagram of initial board drawing:
Meghan's amended drawing (with a few less background images, and my best attempt at explaining how the system works from current knowledge):
The reference and return photodiodes will convert the light signals they receive into current; from that current, we need information about what wavelengths of light were received. From searching basic information about photodiodes, they have a response parameter (speed/time) determined by the materials out of which they are made, which affects sensitivity in different wavelength regions. For example, PIN photodiodes are faster than P-N photodiodes.
This example PIN photodiode seems to be sensitive to IR and visible light, and has a parameter \lambda_0 which seems to indicate the wavelength range in which the photodiode operates well.
Chris' comments Oct 24: Woo Hoo! Well done! As I look at this we can just use the beamsplitter to capture the outgoing light onto a photodiode at the top. We like (and have on hand) Hamamatsu 2281 photodiodes. They mount well in standard 1-inch mounting hardware.
Meghan response: Just to make sure I understand, the beam splitter would be placed where I have the two optical fibers magically breaking apart from one another (in the labeled place in below diagram)?
Hamamatsu 2881 photodiodes [datasheet] are silicon-based and have a relatively large photosensitive area (100 mm^2); the spectral response works great with our desired wavelength range (~450-750nm), as expected!
Tasks (10/24):
- Begin thinking about lock-in design
- We want to deconstruct the signal received at the return photodiode with respect to the signal at the reference photodiode
- Review lock-in notes
- Background material/reading
- Look at some Hubble diagrams, supernova classification
- Figure out how to LaTeX in Wiki/set up package to do so!
- GPT said use LaTeX syntax enclosed in '<math>' tags to TeX – workspace settings did not allow this
- Looking through more wiki documentation it seems Confluence is in this workspace
- GPT says: Confluence, a popular wiki software, supports LaTeX through the MathJax plugin. You can enable MathJax in Confluence to render LaTeX equations.
- apparently, if MathJax is enabled in Confluence, things should show up as TeX if you put them in dollar signs; however, I tested this below and it did not work.
- How to enable MathJax plugin without Confluence login?
- Come up with a project name acronym (MOAT = Monitor Of Atmospheric Transmission currently)
- word possbilities: retroreflector, aerosol, detector, multicolor, automated, lockin, collimated, etc.
DART - Detection of Aerosols with Retroreflector Transmission ? not entirely clear