Picked up another light source. My previous broadband purchase was a UV light , and since I was deficient on the other side of the visible spectrum, I grabbed an IR source LED flashlight. I snuck into the lab to measure the spectrum, because we have an analyzer that covers 600-1700 nm. Just popped the flashlight onto the input jack (for fiber) and that coupled enough light in to make a measurement.

Here’s what it looked like:

The early scans were smooth, so I’m not sure if the couple of dips in there are a result of some setting I changed, or if it’s a real effect (perhaps of heating up — the flashlight gets warm after a while, and this is a scan of the output after it was on for a few minutes)

This isn’t the first (nor, I expect, the last) test of something mundane, just because the equipment is available. A few years back there was a rumor that the US $20 bill had an RFID chip in it, located in Andrew Jackson’s eye, as “evidenced” by bills burning at that position when microwaved. A colleague and I tested that with a network analyzer, since an RFID chip should have a strong absorption feature on resonance. Nada. Not surprisingly, it’s an urban legend. (I swear it’s not there. Trust me: I work for the government)