Continuing with the same battered sunglass lens:
It’s now oriented with the back side of the lens toward the unfocused beam going into the laser head.
The front surface remains undamaged after two pulses at 500 ms 50% power:
The red disk in the middle of both wounds is new this time.
As seen from the rear, the first pulse shattered the rear glass layer:
The image is about 7 mm from side to side.
A chip of glass popped out of the upper part of the fracture, but the other pieces remained in place.
The distinct blue ring is 3 mm OD and marks the inner boundary of a purple disk surrounding the central burn. The disk appears only in reflected light (which is impossible to photograph with any setup I can manage), suggesting it comes from diffraction in a surprisingly uniform air layer blown between the glass and the plastic polarizing sheet.
Also seen from the rear, the second pulse produced a neater wound:
The blue ring is again 3 mm OD and the image is 7 mm across.
The central red spot probably comes from damage to the polarizing sheet.
The most surprising things, at least to me, didn’t happen:
- the glass lens didn’t disintegrate
- the laser beam didn’t punch completely through
Protip: Don’t depend on ordinary glasses, even fancy sunglasses, to protect your eyes from CO₂ laser beams.
5 thoughts on “Laser Cutter vs. Mirrorshades: Rear”
Would it make me a bad person to say this experiment brought to mind myself as a five year old with a magnifying glass on a sunny day?
Only if it involved a sibling …
I can’t imagine the kind of derangement that would lead anyone to ever try that … but surely the more interesting test is to stick them atop the Gentech ED-200 and see how much power gets through.
Now that is a great idea!
Keeping in mind of course that your beam is probably 100% polarized…
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