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Why lasers are so brilliantly useful (www.economist.com)
136 points by prostoalex 9 days ago | hide | past | web | 91 comments | favorite





A lifetime ago I worked a retail job. I’d often say to coworkers “isn’t it amazing we get to work in the future, we get to use laser beams all the time!” They’d stare at me blankly, and I’d squeeze the “laser gun” I was holding in my hands to scan a UPC. The most I’d ever get was a groan like I’d told a dad joke. No one was ever impressed.

To me it’s amazing how such wondrous technological advances become mundane so quickly, the future is here and nobody is astonished.


On the topic of how wondrous technologies become mundane, I find it amazing how we surpassed some of the magic from Harry Potter, and no one is impressed.

The first book was published in 1997. The characters have very handy magic wands, which among other things can be used as flashlights. They can send magical letters (howlers) that can yell at someone in the sender's voice.

Fast forward to 2021, and suddenly everyone is walking around with a fancy tool in their pocket that can be a flashlight, instantly video chat with people, and answer questions on nearly any topic.

Even the offensive spells seem inferior to modern weapons. The wizards have to recite an incantation for every shot, while assault rifles can spray 900 rounds per minute.


I graduated high school in 2004. It constantly amazes me how far we've come.

Back in the 90s, CDs were the height of getting music. 1 disk would carry around 24 songs. That's it. The internet was accessible, but limited to around 56kbps on a desktop. Mobile data wasn't a thing. Texting wasn't a thing. Cell phones were barely a thing, but coverage was practically non-existent.

Most people got their media only from broadcast stations. You had radio, television, and the newspaper and that was pretty much it.

The fact that data is available pretty much everywhere is incredible. Even in the last 10 years, we've went from data being only available in the cities to being able to stream video in all but the most remote parts of the US.

On top of that, something not really appreciated by the general public is just how good codecs have gotten. It is INCREDIBLE what can be done with the same amount of bandwidth we had in the 90s. AV1 + Opus can very nearly stream SD content at 56kbps! 1Mbps wasn't enough for SD content with MPEG2 and MP3 audio. Now, 1Mbps is enough for 1080p HD content.


I'm 50.

We had cassettes and vinyl. I didn't have a Sony Walkman but my first personal cassette player was similar. It was too big to go in a pocket and was generally worn clipped to a belt or on a shoulder lanyard under your coat. By the time I went to Plymouth Poly (UK) in 1989 your cassette player was small enough to fit in the breast pocket of your sleeveless denim over jacket (over the leather jacket that is!)

My first home PC was a ZX80 with 1Kb of RAM - not all of the 1Kb was available. Later I had a C64 which nowadays has a USB interface - I re capped it, sorted out a few other details and got it going again. The first game I played on it in 2018 when it sparked up was "attack of the mutant camels" - a Jeff Minter classic.


>We had cassettes and vinyl.

Which are both still being manufactured :)

I'm 35, I remember in 7th grade when the industrial tech teacher told us that "one day in the future, you'll have this little cube in your hand mimes an inch or so cube that holds hundreds of CDs worth of music and that is how you'll listen to them" Yeah, sure Mr. Pedigo... fortunately he lived long enough to see the iPod come into existence before leukemia took him way too early.

You can have an obscene amount of music on this tiny little sliver of a micro SD card but we still have artists putting their albums out on cassette and vinyl. It's so strange and wonderful at the same time.


Oh man, I remember laughing about that exact idea. Though, at the time it was going to be "holographic storage" which never seemed to pan out.

We never envisioned that NVMe would end up being the storage medium of choice for pretty much everyone.

I still remember my first 128MB usb drive. At the time I was like "Wow, this holds about 100 floppies worth of data, insane!"


We learned we could double our floppy disk storage capacity by using a hole punch to cut a notch out of the sleeve and flipping it over.

I remember: how much it sucked none of the radio stations around me played the music I liked.

how I wanted to learn advanced math topics, foreign languages, etc, but there was no way for me to learn it.

How amazed I was when our school library got those encyclopedia disks and we can look up a lot of things

how I use to dial home with 2 rings to signal my mom to pick me up at school. Telephone company eventually gave us a huge bill.

when I wanted to experiment with linux and other various tech, but getting ahold of hardware to experiment with was too expensive for me.


Right there with you. My first linux machine was an old Pentium 2 Gateway box :D.

I also grew up in idaho mountains so you can imagine how bad radio stations were. Nothing but talk radio and one "hits" station.

Napster was a small lifeline into the rest of the world, though for the longest time we were 5 to 10 years behind the rest of the world when it came to things like pop music. It was bizarre!


I vividly recall getting a Diamond Rio PMP300 in the (late) 90s. 32MB of flash memory and hardware mp3 player. Took one AA battery.

My friend got one and would throw it against the wall—he had headphones with long a cable—to show how it didn't skip (unlike our portable CD players). Until the battery door broke. (He taped it on, but stopped throwing the player.

I eventually got the fat iPod, the first 20 GB. I loaded my whole library and could listen to whatever album I wanted on my walk home from school in the winter.


I'm not from the US, at what age do people typically graduate highschool?


See also: Why Harry Potter should have carried an M1911 [1]

[1]: https://www.reddit.com/r/guns/comments/gwl0v/why_harry_potte...


I get that this is not entirely serious, but it's easy to build a case for why muggle weaponry would not pose a serious threat to witches/wizards in the harry potter universe. the series makes several references to passive defensive enchantments. if the entire campus of hogwarts can be made almost impenetrable to hostile magical forces, it doesn't seem like much of a stretch to imagine that robes could be enchanted to be bulletproof. a skilled enchanter might be able to create passive defenses against most/all conventional weapons.

If Bellatrix Lestrange could go for throwing knives, I feel that guns, and especially snipers, would be pretty effective at assassinating witches/wizards. Most of them doesn't seem to be putting up a shield all the time.

Reminds me of a light novel, where the MC used witches' magics to bootstrap his industrial process, instead of fighting directly with magic.


>eminds me of a light novel, where the MC used witches' magics to bootstrap his industrial process, instead of fighting directly with magic.

Out of curiosity, do you recall the title / author?


Surely if wizard robes can be enchanted to be bullet proof then throwing knifes can be enchanted to pierce bulletproof armor.

I have a sketch of a HP fanfic short story I should really flesh out one day. It involves muggles launching an operation to retrieve a key person from Hogwarts just as the final battle with Voldemort is about to erupt there. The story would follow a bunch of SAS soldiers who fly in on helicopters, while covered by a wing of fighter jets that intercept a dragon, and then provide distraction / air support for the good guys. The overall tone was meant to be similar to the start of Gulag mission from Modern Warfare 2[0].

I'm not a good writer, so this will likely end up a military porn story to the tune of Salvation War[1] - so perhaps it's best if it remains unwritten. But really, if you think about it, the Wizarding World wouldn't stand a chance against even single organized operation by a modern muggle state military.

--

[0] - https://www.youtube.com/watch?v=BDX5uToKuPY

[1] - https://tvtropes.org/pmwiki/pmwiki.php/Literature/TheSalvati...


Not HP, but see https://www.goodreads.com/book/show/24997064-the-nightmare-s... which pits elves and dragons against the British military and intelligence services. All books in the Laundry Files, of which this is one, are great reads.

Oh, 'cstross is still writing Laundry Files? Awesome! I've read up to book 4 or 5, then dropped for reasons I don't remember. Time to read it all from the beginning then; thanks for reminding me.

My favorite little bit of the series so far was how humans eventually figured out what makes Basilisks tick, managed to replicate it on an FPGA, and turned CCTV cameras into defense turrets.


The fidelius charm violates every known law of information theory and machine learning heuristics, not to mention the philosophical implications.

Which isn’t much compared to the amount of space-time that gets manipulated during the series. Literal time travel, giving items more space inside, than that take up externally etc.

Most of the spacetime manipulation are still within the realms of physics, or at least can be reasonably described as long as you change a few assumptions e.g. the existence of negative mass, an infinite energy source etc. Only the time turning and fidelius have actual philosophical implications and former has been thoroughly studied and debated in both normal philosophy and natural philosophy.

Can you explain?

"The Fidelius Charm (incantation unknown) is an extremely difficult, multifaceted and potent charm that can be used to conceal a secret inside an individual's soul; the witch or wizard who houses the secret is known as the Secret Keeper.[1] A dwelling whose location has been protected by this spell is then invisible, intangible, unplottable and soundproof. This is an extremely old spell, one of the most ancient of all."[0]

it's sort of like an in-world deus ex machina device, much like many of the spells and artifacts in the HP franchise.

[0] : https://harrypotter.fandom.com/wiki/Fidelius_Charm


The most important crux of the matter is that it can hide both a posteriori and a priori knowledge. An existing piece of information in the world can literally be rendered unavailable except to a select group of people.

In the book:

> As long as the Secret-Keeper refused to speak, You-Know-Who could search the village where Lily and James were staying for years and never find them, not even if he had his nose pressed against their sitting room window!

This raises a lot of uncomfortable metaphysical and epistemological questions. Is this a purely psychological effect? Or does this operate on the information itself? If it operates on information itself, how big can you scale the effect?

Ignoring magic, if such an effect truly exists, what are its implications for information theory? (Especially since the information is clearly not destroyed as the spell can be undone.) Information itself could become weaponized. Can a RAM bit flip be triggered though the application of such an effect? Or is this effect purely mental?

What about second and third order effects? Does the effect propagate? Assume a machine learning system with the following knowledge/word vectors: Food + Italy = Pasta. If Italy is placed under the fidelius, are the vectors and weights going to magically re-arrange themselves? How will people talk about the dish pasta?

Of all the spells in J.K. Rowling's world this is probably the most creative/disturbing. The whole gimmick with the seven horcruxes is merely distributed systems theory applied to a lich's phylactery, a concept that can be traced back millennia to various ancient civilizations. Splitting and and anchoring soul has nothing on arbitrarily erasing, manipulating, and restoring information itself on an infinitely large scale.


Even Star Trek with it's PADD was susperseeded but it's just normal for people...

Flashlights, cell phones, and assault rifles all existed in 1997. There was no portable internet access, but Harry Potter didn't have that either.

Assault rifles, certainly, were already superior to offensive spells in 1997.

Cell phones existed, but they were just phones and few people had them. Now everyone walks around with this multi-tool that's of comparable utility to a magic wand. Phones now have a flashlight, camera, calling, video chat, maps and navigation, Google, real-time language translation, etc. The Harry Potter series doesn't have magic versions of all of these abilities specifically, but they all seem like things that could have seemed magical in 1997. In 1997, you might think having a map that updates your position live, or can automatically find the nearest burger restaurant is really cool and magical.

If you've ever fantasized about what it would be like to live in a world with magic, here's one perspective: we do live with magic, and you get used to it.


Reminds me of that Louis CK bit about internet on aeroplanes: https://www.youtube.com/watch?v=nUBtKNzoKZ4

"You’re flying! It’s amazing! Everybody on every plane should just constantly be going: “Oh my God! Wow!” You’re flying! You’re sitting in a chair, in the sky!”"


I think bringing back that absolute bafflement intentionally once in a while is good habit, especially for people working in technology.

I am constantly amazed that computers work at all. The more I learn about it the more amazed I am that anything works. Especially software wise I see soo much duct tape on so many layers, like looking at a house of cards that could (or rather should!) crumble down any minute, because it seems to defy reality.


My illusions of technology were lifted after a course in advanced computer architecture. The true technical complexity is unfathomable enormous. I mean, correctly flickering 3 billion times per second on nm scale and being super sure you got the designs right? Cannot imagine.

And even if you did get everything right, every now and then a friggin' cosmic ray zaps through just in the right way to flip that one bit in your memory.

And just skipping over the running out of money thing.

Old enough that ATM's were a big change.

Before that, it was a Friday trip to the bank to get cash for the weekend. Credit


Haha... this is so true.

When I toured some kids around the Stanford cell therapy lab, filled with over a billion dollars of cutting edge equipment, the thing they were most impressed with was the eye wash station.

They MARVELED at the damn eye wash station. Technology that has been around for ... over hundreds of years and otherwise hasn't really changed. They asked more questions about the damn eye wash station than anything else, lol.


Yes,sometimes we need to be reminded: https://youtu.be/yFj46Ei61Mg [7:30-8:00] I nearly took off the sofa just by watching it.

Back in 2008-9 or so I had a 3g altel phone during the Verizon merger. If I forced my phone to 3g I could connect to Verizon towers. It was such a great feeling tethering my phone to my laptop to play WoW at 70 MPH.

*I wasn't driving. Also horrible ping.


Uni in 1995 and saw my first browser. Now I can drive in Africa while having a voice chat over my phone data with a friend in Chicago or Sydney.

When I was a child I'd often stare into the laser scanners at store checkouts in awe. They were so cool. Full of rotating mirrors and lasers. The modern handheld ones are a little less cool.

But, re: "why lasers are useful", it's in the name. They're a way to get a spatial and phase coherent light source that's actually high power. In the old days they'd have to take a mercury arc lamp and put a pinhole in front of it. The pinhole gave it coherence but traded away all the intensity.


I just bought a proper $250 Zebra scanner for some personal inventory projects / projects that utilize pdf417 and data matrix 2d bar codes and I have to say... this is the absolutely coolest piece of "plug and play" tech I've bought in years! Granted, these scanners largely use machine vision tech but lasers are still used as a form of "dumb" auto focus aid.

On another tangent, I still CANNOT believe that one company at least within the US controls 100% of the issuance of UPC codes. They sell them for up to *$30 A PIECE*! We need a "LetsEncrypt" for UPC codes - granted they serve an important role in load balancing across online stores, preventing counterfeit goods and in Amazon's case... penalizing sellers when they find the same UPC being sold on another online platform at a lower price ;)

Lasers will always be cool


"the future is here and nobody is astonished."

Maybe thats because that is always the case (even though progress accelerated).

But since for most people the future still means they slave away in a boring job, that might be a reason they are not thrilled all the time.


on a similar note, most people only get to experience "future stuff" after it has been relentlessly optimized for cost to the point where it can be economically deployed at scale. a lot of the coolness has been stripped out at that point.

on a couple occasions, I've flown in small GA planes. a bit bumpy for my tastes, but there really is a sense of wonder and awe when you can just ask the pilot to fly anywhere and see what stuff looks like from the sky. I don't get the same feeling on commercial flights; I just experience being stuck in a metal tube with beige plastic trim for a few hours. I'm still amazed by what computers can do, but to most people they are just "the thing I use to browse instagram".


> To me it’s amazing how such wondrous technological advances become mundane so quickly, the future is here and nobody is astonished.

When they're ubiquitous they lose a lot of wonder. But furthermore, a lot of these advances are buried/not directly visible to the end-user. Think of a CD player: You use a laser to produce sound from (what apppears to be) a smooth plastic disc.

I bet the concept of the wheel was pretty damn wondrous in the beginning too.


It was even more exciting two lifetimes ago.

In short order people got electric light (magic! just flick a switch), phonographs (on hearing one, people apparently went looking for the soprano behind the curtain), moving pictures (there are stories of audiences being panicked by a film--black and white, 16 fps, grainy, silent, and all--of a train coming toward the camera), radio (plays, orchestras, and other entertainment from hundreds of miles away), and all sorts of wonderful houshold appliances like refrigerators, vacuum cleaners and electric heaters and stoves which saved tens of hours per week. And glow-in-the-dark radium watches, and telephones.

Having lived through these (in a rural area, things came a bit later than in the big cities) my mother-in-law was unimpressed by the movies about Buck Rogers rocketing around the solar system and Dick Tracy's video wristwatch, taking them as just things that hadn't made it to her town yet.


I get you. And it's not just lasers, it's so many more. Sometimes I catch myself thinking that the technological progress is quite slow, but then I slap myself in the face to remind myself that in just couple of decades we ended up having devices in our pockets just like those from sci-fi films!

Lasers are great tech,I used to be fascinated by them when I was a kid devouring science literature. I hope I'll more great use cases in the near future.


That is how I feel about WiFi. The fact that you can send out large amounts of data on shared channels is amazing. It is astonishing that it works as well as it does.

Mitchel and Webb did a very funny sketch about this

https://youtu.be/8HgejSCHRi8


Maybe they knew it was a cheap CCD unit (I admit, not likely if it was the multi-directional units you have at checkouts, etc.)

Lasers revolutionized medicine, particularly in two specialties where the organ is accessible to light: dermatology and ophthalmology. We use : - excimer laser (UV) for their photoablative properties, to change to anterior corneal radius of curvature in refractive surgery (fun fact: the first attempt to use this laser was pure serendipity : "oh I got this excimer in my lab, here is a chicken sandwich, let's see what is gives on organic tissues") - ND:Yag laser to pierce a small hole in the iris when it is necessary to establish a communication, or to locally break the posterior lens capsule when it opacifies after cataract surgery ; those two procedures where far from benign when they had to be performed surgically , today it is made in the office in a few seconds - femtosecond lasers to cut a thin layer of cornea , which is lifted , before applying the excimer laser, in LASIK procedures - diode lasers to reduce the intraocular pressure by destroying parts of the ciliary body in very specific cases - various lasers to photocoagulate lesions on the retina....

Ophthalmology without lasers would look like a middle-ages practice.


A few more I can think of, Laser Doppler imaging of blood vessels, and certain types of oxymetry also use laser diodes instead of LEDs.

Laser is pretty much everywhere.


In high school, my physics teacher told us about his time at Glasgow University where he’d worked on Scotland’s first laser. This would have been in the ’60s. He said it was fascinating, but they had no idea what to do with it then. He called it “a solution in search of a problem”.

I once read that they needed a powerful energy source for nuclear fusion. In the fusion bomb they could use a fission bomb as source, but that was overkill for a fusion reactor.

Then someone invented the laser and it was like you build a cart and someone with a horse to pull it came around the corner.


The phrase “a solution in search of a problem” really reminds me of block chain. It's a really cool piece of tech, that so far has mostly enabled speculative investing and anonymous drug trade.

I disagree. It's a neat solution to exactly one, pretty theoretical problem: how to have digital currency without any trust involved in the system whatsoever.

And nothing else, because tracking things in the real world instead of currency requires trust that what's on the chain really is what is in the real world, and besides there are lots of highly trusted institutions in the world that it's not practical to do without, like the judiciary system.


No, a neat solution to one, not at all theoretical problem: how to maintain a append-only database (eg mapping domain names to registrant public keys and (less critically) append-only lists of signed IP addresses) without giving any participant the ability to either redact the database (eg remove the registration for thepiratebay.org) or prevent (specific or any) future appendments (eg, prevent new IP addresses for thepiratebay.org).

You're quite right that "solution in search of a problem" is not accurate, though.


Well you need protection against 51% attacks, which means you need it to be very expensive to get that many modes, which means the people running nodes need to be compensated for their expense.

Which can be done neatly by having the things in the database have value, so that the reward can also be inside the system, i.e. mining coins.

Other databases people come up with always have problems with 51% attacks, so the system isn't made completely open, so it's pointless because then more traditional solutions are better.


> Which can be done neatly by having the things in the database have value, so that the reward can also be inside the system, i.e. mining coins.

Sure, but that's a mechanism, not a goal.


I studied physics at Glasgow. You can still see the pipes in the ceiling of the corridors on the ground floor of the Kelvin Building which were intended to be used to heat the building using the laser's cooling fluid. That was apparently the only way they got permission to install something requiring so much power! I heard though that the laser coolant was never actually used for heating in the end...

Thankfully it found quite a few problems to solve.

I think "a solution in search of a problem" isn't a bad thing the more it's closer to first principles. It's another meaning when the solution is farther away from first principles.

Optical Tweezers. Basically people use lasers to move microscopic particles around. Lasers can also levitate things. Here's a really interesting video on this topic. https://www.youtube.com/watch?v=Sq7GaO8iqu8

I think anything that does a controlled, specific, and consistent behavior is typically much easier to use in an experiment or utility. A laser is like a log statement for light.

I'm pretty excited about the future of VCSEL technology. Not only is it profoundly useful for lidar and stuff, dense arrays of lasers could also be used for all kinds of display technology.

If we can somehow make cheap VCSELs that emit blue or green light, red, green, and blue VCSELs could even take over general purpose lighting. One imagines a TV where each subpixel is a VCSEL. It would potentially be better even than microLED displays. The spectral purity would give really amazing colors.


Tangential, but there are so many common in-use technologies we should be in awe of but aren't. I mean, just look at the average home or apartment built relatively recently.

For example, we have reached standards of insulation, weather-proofing, and energy efficiency that would just blow the mind of any builder from just 30 years ago (not that there isn't room for improvement).

It's not flying cars or robot butlers, but it impresses me at least.


I’ve been interested in applications of visible light for a short time now, but I started watching styropyro videos on YouTube even more recently and find myself suddenly interested in lasers, even for stupid, impractical usages.

My solid state physics teacher at university used to joke that lasers rely on oscillation rather than amplification so they should be called losers. It didn't stick because no one likes a loser.

Mitchel and Webb did a very funny sketch about this

https://youtu.be/8HgejSCHRi8


This article should have been titled 'The Real Genius Behind Lasers'.

Non paywalled link: https://archive.is/ho2FH

Technically it should be LASER, since it's an acronym.

I am part of an organisation called the LAAC, which is the LVK Academic Advisory Committee. The LVK is the LIGO-Virgo-KAGRA collaboration. LIGO is the Laser Interferometric Gravitational-wave Observatory, and Laser is Light Amplification from Stimulated Emission of Radiation. So the L of LAAC is a 5th order initialism...

It makes you want to address a paper to:

Light Amplification from Stimulated Emission of Radiation Interferometric Gravitational-wave Observatory-Virgo-Kamioka Gravitational Wave Detector Academic Advisory Committee.

It's like looking at the preprocessor output from some template heavy C++ code.


Reminds me of

GTK which stands for GIMP Toolkit where

GIMP stands for GNU Image Manipulation Program where

GNU stands for GNU is Not UNIX where

UNIX stands for Uniplexed Information and Computing System

And on top of that there is a variety of software built on GTK whose names are acronyms containing a G that stands for GTK.


By now the word laser is so common that it is a just an uncapitalised word accepted by major dictionaries [1][2]. There are also inflections (lased, lasing) [3]. Nobody spells it in all caps now. Likewise with radar and soon lidar.

[1] https://www.lexico.com/definition/laser

[2] https://www.merriam-webster.com/dictionary/laser

[3] https://www.lexico.com/definition/lase


It's since entered the vernacular as just "laser".

https://www.merriam-webster.com/dictionary/laser


We've even backformed a verb, "lase".

English does whatever the hell it wants, doesn't it

You know what gets me though? When they say “laser” (however capitalized) in sci-fi stories that are set in a different universe...

Or any other terms that specifically evolved in Earth societies and cultures, like “katana” in Dungeons & Dragons and so on.


> any other terms that specifically evolved in Earth societies and cultures

That's true (pretty much by definition) of literally every word in English, though. (Yes, "katana" is a english word; the fact that it's derived from a japanese word (namely "刀" aka "かたな") doesn't change that, any more than "pizza" (italian) or "beef" (french, a long time ago).)




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