how the laser happened

you could build a laser in your living room if you want to

I was thinking of amplification to improve night vision.

Because bioluminescence doesn’t get anywhere near the pumping rate required for a visible laser.

That’s more of a theological question. ;)

Cheers

Phil Hobbs

You can build a monster N2 laser using FR4 and some flashing copper, plus a low current HV supply. See C. L. Stong, Scientific American, June 1974.

Cheers

Phil Hobbs

Nature chose the cheaper way: A cascade of amplifiying chemical reactions.

Jeroen Belleman

More interesting still nature beat him to it.

The natural source W3(OH) dense molecular cloud which has hydroxyl masers pumped by UV bright young stars embedded in it.

Very bright ultra narrow band point sources on a fuzzy nebulous object.

They would have needed to make the mirror just cavity right though.

A nitrogen gas UV pulsed laser is possible just by getting the pressure right and creating the population inversion. Self starting - there was a (dangerous) experiment in SciAm Amateur Scientist column to do it sometime in the 1970's. June 1974 in fact - cover shows the BZ reaction.

Much like Helium was in the sun but more pervasive.

He published first though. ;)

Cheers

Phil Hobbs

A photon might be absorbed and lost without invoking a chemical response in the retina, and be wasted. A lossless preamplifier would help.

There would be bandwidth issues, but nature is inventive.

The idea could be experimentally tested, fairly easily.

I know a guy who built a HeNe. It wasn't hard.

T>

Too many powerful old farts declare things to be impossible.

Jeroen Belleman

I helped do that at a former employer in about 1972. Sorry, no photos. The laser was used to trim resistors on ceramic hybrid twin-T CTCSS (continuous tone controlled sub-audible squelch) for the 2-way radio business. Sorry, no easy to find photos, but I do have some sample hybrids buried somewhere.

As I recall, we initially did everything wrong. But eventually, all the parts, pieces and processes were convinced to function properly. My favorite "oops" was when someone decided to mount the laser tube on a brick wall. That actually worked well until someone mentioned that there were train tracks on the other side of the brick wall. I have some hybrids where the laser trim line resembled a seismograph plot.

In retrospect, it really wasn't that difficult to build if we had followed the instructions. Just one problem... there were no instructions in 1972.

I have the book "The Scientific American Book of Projects for the Amateur Scientist" circa 1960. There are more recent versions available:

Here's a list of some powerful old farts and their pontifications. The list has been useful in the presence of experts, consultants and non-technical managers. I don't recall from where I stole it:

Of course the Ringworld is dynamically unstable, so it wouldn’t matter that much if it got hit. ;)

Cheers

Phil Hobbs

Yes indeed. Niven invented a plot twist to fix that in "The Ringworld Engineers". Dyson spheres aren't stable either. We're making some headway into making a Dyson swarm though. ;-)

Jeroen Belleman

.

This is often paraphrased as "Science progresses one funeral at a time".

Joe Gwinn

I see the same thing in electronic design. People favor accepted practice, validated in textbooks, and apply all their intelligence to showing how new ideas won't work.

A recent case is deciding that the LC's at the output of a switching power supply are "a filter" so must follow classical filter theory, pole-zeros and Butterworths and such. I tell them "It's just a power supply."

When I was a graduate student I put together an He laser tube with Brewster angle windows, and getters, and loaded it with the right gas mix. It did produce the right sort of glow when I ran a discharge through it

The friend who was going to fabricate the metalwork to locate the tube between the two properly aligned mirrors didn't get as far.

Many more ill-informed half-wits make the alternative mistake

He published Einstein's four 1905 papers without bothering to get them refereed.

I can't say I've seen that. I've seen quite a few bad ideas put up by people who should have known better, but since some of my occasional good ideas have (even more occasionally) lead to patents, it doesn't reflect my experience.

In other words you don't know much about filter theory, and couldn't justify the damping factor you had chosen. Heavily damped filters tend to be much more phase linear than the more lightly damped faster-rolling off variants.

"It's just a power supply" is a pretty obvious cop-out.

Evolution proceeds by making random changes. The changes that survive have all had to work better than the system that preceded them.

Creatures that fluoresce use the light they generate to their advantage, but it costs them energy to create it. Creating a population inversion costs a lot more energy than exciting a few molecules, and it isn't likely to do anything useful when it crops up at random.

It's like error-detecting and correcting codes - our genome should exploit them, but doesn't, because getting half-way there doesn't generate an advantage.