A 600nm emitting semiconductor laser for only 5$?!

[18LJ]

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Ok ill admit to the obscenely clickbait-eyness of the title but i couldn't help myself and I know that people are gonna see the thread title and instantly their bullsh#t alarm goes to defcon 10x ready to tear into this fool claiming to know of magic diode beans that emit wavelengths that exist only in legends and fairly takes....but check out the link. I found it to be fairly compelling/reasonably plausible. I've long been aware of people temp shifting wavelengths from ur everyday run of the mill 5$ red diode but until I stumbled across this site I had no idea that adding pressure would dramatically increase the effects of temp shifting the color. So ya a 5$ red can be shifted waayy down to 575nm...as long as you have a few grand worth of lab equipment lying around. Has anyone here ever tried putting diodes under pressure before? I don't have the means or expertise to attempt this (nor the courage... )A quick search for a conversion table told me that @ 20kbar we are looking at: 20000 Bar = 290075.47546 Psi.... If that's correct then any sort of equip mistake or defect in your gear would result in a almost certain lethal catastrophic failure of the pressure chamber. For comparison a standard m4 5.56 NATO rifle with gas piston located at 13.2" will have a internal pressure within the barrel of ~19600 psi before the round passes the gas port. So almost 14.8 times greater pressure than the barrel of a m4.... I think. Anyway I was impressed with this research project, its awesome work they're doing and thought I'd share it and wanted to see if any of the OG's around here have any experience trying anything similar to this. U guys think that the same color shift world work for green or blue diodes or would this technique only work for the semi-con crystal structure that produces red/infared wavelengths? I didn't see anything on the site saying it wouldn't but the research was focused solely on red and infrared so maybe I missed something? Anyways...enjoy the link

 

[RedCowboy]

FYI the M4 uses direct impingement not a piston, however the M249 and SCAR do use a piston as well as some civilian AR-15 variants and although there is no NATO standard rifle, STANAG standard round is the 5.56 and also magazines are standardized so all the various NATO rifles can share mags and ammo.

 

[18LJ]

Ya i was just referring to the NATO standard round. The first link that came up kinda referred to the ar15 and m4 loosely and interchangeably. And I realize the pressure will vary between rifles and barrels and there's a million different things that influence the pressure and velocity. I just wanted something to compare the pressure to and that's the first thing that came to mind.

 

[RedCowboy]

Sure thing, I just saw the M4 quoted and had to add my 2 cents.
BTW the case pressure is as much as 62,000 psi and as you mentioned the gas system pressure depends on barrel length and gas system length ( pistol, carbine, mid length, rifle ) although technically the M4 has a 14.5 inch barrel and carbine length gas system as it's by design a shorter variant of the M16A2.

Of course without the barrel to make use of the expanding gas the projectile would never gain it's velocity so if we think about a pressure vessel that holds 50,000 psi and what would happen if it ruptured/cracked, well it could be simply a venting albeit a loud venting or much worse.

Here's someone who had a squib and didn't clear his barrel, that's a bad reload with no powder where the primer lodges a bullet in the barrel and if you chamber a round on a plugged barrel BOOM