Glass slide experiments
Experiments using sections of ordinary glass for an output coupler. A single microscope slide was tried first, and a surprisingly good output was obtained (see 1st. and 2nd pictures). I then directed the unfocused output onto a piece of charred wood, which appeared to indicate that the output was relatively energetic (3rd picture). Inspired by this, I cut several DIY slides using ordinary picture frame glass. I then combined two of the makeshift slides, and obtained a more energetic output than when using a single glass slide.

I tried burning through a razor blade using the 2-slide output coupler. To successfully do so, I had to carefully adjust the razor with respect to the lens focal point - several failed attempts were made before the focal point was located (see the 5th picture). The energy level with 2 slides was such, that precise focusing was required in order to pierce the razor.

Finally, I tried using 3 slides. They had to be pressed together so that beam reflections were combined, using a HeNe laser. Interference fringes were produced by the tiny spacing between the slides, and the reflected HeNe spot appeared to cycle in intensity as the slide was moved across the path of the beam. When installed as an OC in the ruby laser, a more energetic beam was observed in comparison to the setup using 2 slides, but alignment was not very good (as seen in the 4th picture). After making careful adjustments to the alignment, a really bright and energetic output was observed as shown in the 6th picture. It easily chewed through a razor, and did not require as much fiddling with the focal point as before (7th picture). I then directed the unfocused output onto a piece of charred wood (8th pic), and some charred cork (9th and 10th pic).

The crude plate glass output coupler can be seen in the 11th and 12th pics.

This is an ongoing experiment, but the credit goes to Douglas Little who I want to thank for suggesting this.
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