A Look At Lasers | Ruby Laser, Fiber Optics, Laser Cleaning
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- Опубликовано: 4 авг 2020
- For years lasers have been a hallmark of science fiction. Though, much of our
modern technology depends on them even throughout our daily lives. Some noteworthy examples include range finding devices, optical communications, and of course, even barcode scanners. The unique properties of laser light that make this possible are:
Single wavelength
Narrow beam and
Great Intensity
Additionally, laser stands for "light amplification by stimulated emission of radiation". The unique characteristics of lasers even allow surgeons to reattach retinas, further underscoring their value to modern medicine. An injury can cause the eye’s retina to peel away from the supporting tissue. And without rapid treatment, the entire retina can become detached resulting in blindness. Surgeons can use green laser light from an excimer laser of nearly a single wavelength since that color passes through the eyes lens and vitreous humor and is not strongly absorbed, avoiding further damage.
The laser beam then strikes the retina where the tissue greatly absorbs the light. At this point, the high-intensity light welds the detached retina back into place. The narrowness of the
laser beam enables the surgeon to affect only the area of the retina that needs to
be repaired; in areas as small as 30 microns. How a laser creates light with these three
characteristics is a marvel of engineering.
In 1960 the first demonstrated use of a functional laser was credited to Theodore Maiman at Hughes Research Laboratories, in which he took a ruby cylinder and surrounded it with a xenon arc flash lamp typically used in aerial photography. Maiman’s ruby laser, as it was known, was based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. The intense bursts of light from the lamp initiated the laser process. To better understand how it works let’s look at what happens when applying light from a weaker lamp.
A flash would promote a few electrons from the ground state to an excited state. Subsequently, they would lose a bit of energy, fall to a lower energy state without emitting light and then drop from there to the ground state giving off a burst of light.
Thereafter, the light produced would be called incoherent light which is a spectrum of colors and intensities. However, in order to create a laser, a much more powerful lamp is necessary. In the ruby laser repeated flashes called pumping creates an amazing phenomenon. So much energy is applied that a population inversion occurs.
Population inversion is essentially when more atoms exist in the higher, excited state than in lower, unexcited, or ground state.
Electrons from a population inversion that are returning to the ground state release light that starts an avalanche called stimulated emission. We’ll go into more detail on stimulated emission later in this video. The photon produced when an electron decays, induces other excited electrons to simultaneously decay and release nearly identical photons. Thereafter, coherent light is created which means that the crests and troughs of every light wave in the beam match up. At this point, we have coherent light but not yet the other two properties needed for laser light.
To get a narrow beam with all the light rays parallel and a nearly single wavelength requires an addition to our ruby laser example. To achieve this, Maiman incorporated silvered ends to reflect the light within the ruby cylinder, creating a resonance cavity. He made the two ends of the rod parallel to each other. From top to bottom the distance between these two mirrors differs by no more than two hundred nanometres.
Two important things take place inside the resonance cavity. First, any light rays that fail to line up with the axis eventually exit out from the side of the cylinder, and more importantly the light parallel to the axis becomes intensified and narrowed in wavelength.
At this point, we now meet the three characteristics of a laser.
The way it works is that the mirrored ends create a standing wave. This means that only light at a particular wavelength can exist inside the cavity. By selecting the correct rod length we’re able to get the nearly single wavelength of light, characteristic of a laser. The addition of a small opening in one of the mirrors allows the light to escape, creating the quintessential laser beam. In technical terms, what allows the light to escape is that the mirrors are very highly reflective and only the light that meets the resonance condition will be transmitted out of a pinhole aperture.
Now that we have a better understanding of the fundamentals of how a laser works. Let’s take look at the two main flavors of a laser.
Generally, the operation of a laser can either be continuous wave or pulsed. The primary determinant rests on whether the power output is essentially continuous over time or whether its output takes the form of pulses of light, on some variation of a time scale.
It looks so interesting and clear. But I had too much alcohol and need some sleep. Will watch later, tnx
Cheers 🍻
Ps inebriation may give you absurd thoughts, but those thoughts are based on science lol write them down!
@@GearQuest I'm at 8:10 so far in the video and you've replied, amazing response time 🙏🏼 earned a sub!
Hah me too!
This is the best and most intuitive explanation of how a laser works that I have ever seen! I've seen many diagrams and explanations previously, though they still did quite a bit of hand-waving. Excellent work!
Your channel deserves much more subscribers. Good work. Keep going
WTF?! I spend most of my time on RUclips searching for content based on electronics, optics, and lasers… constantly searching every day or two for new laser content. Using all of the keywords and stuff like that… And this video has never appeared in my recommended search results.
I just stumbled across this video by accident while looking through your channel.
I’m not a professional as it pertains to lasers and optics, however I do Have my own electronic lab,….. i’m self-employed full-time. And Focus predominantly on component level board repair for a wide range of industrial and government clients. My specialty is large industrial control equipment. Like VFD, servo drives, PLCs, CNC equipment, stuff like that. I don’t do the mechanical stuff anymore… I just do the circuitboard repair and troubleshoot boards. I also do a lot of test equipment repair and calibration… With a bit of metrology just to test my patience.
over the past several years, I’ve spent a ridiculous amount of time and energy putting together a industrial grade, scientific and compliant optics laboratory in the corner of my electronics lab.
You can’t imagine how expensive that stuff is if you have to buy it new… even for a basic professional starter set up… You’re looking at at least 20 or 30 grand. Way over my head, especially considering it’s mostly just a hobby. I have no way to justify spending that kind of money on optical equipment…So I went to a lot of government and industrial auction… You can’t imagine the wonderful things you will find… Complete pallets full of unused equipment. Some of my best scores Includ a REAL Industrial optical breadboard, dozens of high powered medical/industrial lasers, and all of the cool optics and other stuff to go along with it!! I can do almost any optical experiment that are common in research and physics in this modern day and age.
It’s so much fun and I highly encourage anyone who’s interested to give it a shot! Start with a small table top setup… With a small lightweight optical breadboard, optics, and all the mounting hardware and lasers. If you look around you can get some sweet deals. Because if you have to buy stuff new from the companies… A single lens or sensor could cost you $400. Or a simple mount mirror mount could be $150! But on the secondhand market you can find stuff gently used or brand new… And you can get a huge box of the stuff for 50 bucks! Do that enough times and really dig around… And you can set up a really nice lab on a shoestring budget.
it really is a golden age of electronics and equipment. If I had to buy all my laser lab equipment at normal prices… It would be close to $50,000. And I paid less than a 10th of that! Spread out over five or six years of course because I’m not made of money.
So although the laser and optics/electronics hobbies can be expensive… You can buy the stuff for 3 to 5% of its actual value! Look around in your area for government and industrial auctions, Auctions in academia, and companies going out of business.
I have multiple kilowatts worth of optical laser power in my lab, all of which was bought for pennies on the dollar… A lot of it new stock… Because the extremely powerful lasers used in industry, For scientific research, and high power fiber coupled lasers used in communications… are upgraded so regularly… That once a new model comes out they absolutely give away the old stuff for Penies…even if it’s new in the box sitting on the shelf.
For example if you weeks ago… I bought three separate Jenoptik modules for $70 a piece new in the box. They’re well over $1000 each, retail… And they are still current technology and whats still used today. It’s not like they’re out of date or anything. And 45 Watts might not sound like a lot… But 45 W of optical output power is enough to slice right through a lot of things. For reference…Those super powerful burning laser pointers you see on RUclips… They’re usually 5 W or less. Usually much less like about a half a watt. So these 45 W and 80 W modules I got a hold of, are pushing an absolute insane amount of power… And they’re really expensive if you have to pay the new price. And I’ve got stacks and stacks of powerful laser modules on the shelf in the lab. And if I had to add it all up, I’ve got at least a few kilowatts of power. If I had to buy just those lasers and pay new prices… Good Lord it would be worth more than a house. And if you look around carefully… You can get the stuff for almost free.
Thank the Lord for the secondhand market and for government budgets and waste 😁
"A look at laser" - Just don't look at a laser beam. It will hurt your eyes.
You got the joke with the title haha. Thanks for watching 🙏🏼
Don't forget about laser welding and cutting.
I once shot a laser through my finger at a convention trying to weld two bb's together
I’m considering a follow up since the subject is so broad. Sorry to hear about your finger 😳
@@GearQuest it stung pretty bad but the cool thing about lasers is they cauterize. So I had a tiny little burnt dot of skin on one side and a tiny little for under my fingernail. And a tiny line across the finger nail.
We all laughed about it and the salesman gave me a hard time. But I got to learn how to laser weld and what happens when your not paying attention.
That machine really was fascinating.
so youre saying that if we reach star wars level of warfare we would be compassionately conducting warfare by healing the enemy while also harming them. As a warning you know@@dimesonhiseyes9134
Typically the green beam for retinal reattachment is frequency doubled NdYAG light; excimer light is almost always in the deep UV, strongly absorbed by eg. proteins, and thus used for corneal ablation in refractive correction surgeries, ie. Lasik.
Did I mention you need a pop filter (to filter out the plosive “p” sounds)?
Yes, you did! Haha
Didn't even know the beams had 2 kinds, thought all of them were pulses.
Why does everyone say that barcode scanners & presentation pointers are lasers? These are just focused light. I don't think that such low voltage can produce a laser. I have even heard some folks call an optical mouse a laser mouse.
Because they have a laser warning sticker
All those bumping particles.
Second!
Wtf is up with this video? It starts off good and structured then it ends randomly with a satellite laser in space. Feels like you failed to upload the other half.
Another half is in the works since this is such a broad subject matter. Usually I’ll make a second part if the first performs well. Thanks for watching 🙏🏼