Originally posted by Jim Morton:
On the subject of inserting a deck of cards in a bottle via laser welding, the question remains: Have you ever actually done this, or is this a purely hypothetical postulation? I suspect that it's not as easy as you make it sound.
It would be very difficult. Carbon dioxide lasers come in two kinds -- CW (Continuous Wave) and Pulsed. The first time comes on for as long as you turn it on, the second dumps it's energy out in a few microseconds.
If you tried a CW laser, you would have to use it as you would a torch; heat up the glass until it fuses together. Glass expands under heat, and does not conduct heat well, so you would have to do it very slowly to prevent cracking/shattering, in which case the deck of cards would most likely catch afire.
If you used a pulsed laser, the surface of the glass would craze (ablate and crack for the depth of penetration, forming a thin surface layer which looks like frosted glass). It wouldn't melt/fuse the separate pieces together, unfortunately.
Also, Carbon Dioxide laser light is mostly at a wavelength of 10.6 microns, which bottle glass doesn't transmit -- it is all absorbed into the front few microns of glass (which is why it crazes).
I used to be an engineer in the Army's high power laser program (back when it had one . . . ), and have done work on the subject of laser/optics interactions. Not as much fun as sleight of hand, but steadier work.