Naked Science Forum
On the Lighter Side => Science Experiments => Topic started by: hamdani yusuf on 24/12/2022 10:31:11
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I just found a great Youtube channel named Les' Lab, explaining how to build DIY laser. I'd like to share the videos here. I hope you find them useful.
Nitrogen Laser tear down, power up, and Home Made Dye Laser Demonstration
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DIY Home made High Performance TEA Nitrogen Laser and Dye Laser!
In this video, I show three of my high performance designs for Home made TEA nitrogen Lasers.
Although Nitrogen Lasers are quite simple to build, they are difficult to build well. My first ever TEA Laser was held together with gravity and glue. The ones demonstrated here are worlds away from those first attempts!
The two Charge Transfer Lasers demonstrated, have high repetition rates, high output powers (peak and average) and are robust, with many thousands of shots possible before the dielectric has to be replaced.
These can easily drive a Dye Laser to threshold, in fact the peak power is so high, Dyes can be Lased Superradiantly (Feedback is so high, no mirrors are needed!)
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Tear down of the DIY High Performance TEA Nitrogen Laser, how to build it and advice!
As some of you guys have asked specific questions about the High Performance Nitrogen Laser build, this followup video shows a tear-down of the Nitrogen Laser head, along with specifications for components and general advice if you want to build your own!
Also someone asked if the whole system could be run on plain air, and this is demonstrated
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DIY Tunable Dye Laser! (HD 60FPS re-encoded video)
In this video, I show a home made tunable dye laser, pumped by a home made Nitrogen Laser.
Tuning of the Laser Dye: 7-hydroxy-4-methylcoumarin is demonstrated from violet to green!
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Dye Laser Teardown and Demonstration
In this video, I show a Commercial Dye Laser, the LSI DCM laser I picked up from eBay. This is pumped by my now refurbished LSI 337i Nitrogen Laser.
Dye Lasers are really col devices that produce laser light from the Ultraviolet - visible - the Infra-red. They're tunable as well!
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Here's another video from another Youtube channel.
How to Make TEA Laser - Homemade/DIY Laser
How to make a TEA laser, an easy to make laser, with step-by-step instructions. A TEA laser is an easy to make homemade/DIY nitrogen laser. TEA stands for Transverse Electrical discharge at atmospheric pressure meaning you use nitrogen in the surrounding air with no control over pressure.
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DIY Supercontinuum Laser! The Ultimate White Light Laser!
In this episode I discuss Supercontinuum Lasers, the ultimate white light Laser! Normally such lasers cost thousands of dollars, but later on, I discuss constructing one from a practical standpoint, on a super tight budget using plain old telecoms fiber!
Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
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Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
How many times have I explained the idea of "lies we tell to children"?
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Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
How many times have I explained the idea of "lies we tell to children"?
Everyone is someone's child.
What's the true explanation, free from lies?
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I just found a great Youtube channel named Les' Lab, explaining how to build DIY laser. I'd like to share the videos here. I hope you find them useful.
Nitrogen Laser tear down, power up, and Home Made Dye Laser Demonstration
I have just such a parata in the garage, I'm going to try to make this one.
Thanks for sharing!
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I just found a great Youtube channel named Les' Lab, explaining how to build DIY laser. I'd like to share the videos here. I hope you find them useful.
Nitrogen Laser tear down, power up, and Home Made Dye Laser Demonstration
I have just such a parata in the garage, I'm going to try to make this one.
Thanks for sharing!
I'd be glad to see your experiment.
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Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
How many times have I explained the idea of "lies we tell to children"?
Everyone is someone's child.
What's the true explanation, free from lies?
The title of the video says itself.
How lasers work - a thorough explanation
Lasers have unique properties - light that is monochromatic, coherent and collimated. But why? and what is the meaning behind he term laser. This video covers are fairly comprehensive explanation of the process of producing a laser beam.
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What's the true explanation, free from lies?
Complicated.
It would probably take a book.
Do you now understand why it's not going to be on the web?
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Here's another explanation.
How Lasers Work | Laser Micromachining | Lasers in Industry | Picosecond Lasers | Ultrafast Lasers
How Lasers Work
Lasers are everywhere and used in a wide variety of applications. They are found in barcode scanners, DVD players, used in medicine, produce dazzling laser light shows and of course, instrumental in micro manufacturing. A laser is a device which generates or amplifies light. The acronym LASER stands for Light Amplification by Stimulated Emission of Radiation. The term was coined by Gordon Gould when he was a student of Dr. Charles Townes at Columbia University in 1957. Lasers exhibit some unique characteristics. They are monochromatic which is to say they output a single wavelength or pure color with an extremely narrow linewidth. Depending on the laser type, they can have wavelengths from the ultraviolet, visible or infrared portion of the electromagnetic spectrum. Wavelength selection is important depending on the material being laser processed. As an example, UV lasers are best for drilling and cutting plastics. Lasers are highly directional where the beam can be as little as one millimeter and spreads very little over distance. In fact, lasers have been bounced off of the moon to accurately measure the distance from earth. And they are coherent where all the waves are exactly in phase with one another.
The common components of all lasers consist of an Active Medium which can be gas such as carbon dioxide or krypton fluoride in an excimer laser to generate high power UV pulses. A solid-state laser has a crystal made of ruby, neodymium-doped yttrium aluminium garnet, or Neodymium-doped yttrium lithium fluoride to name a few. The gain medium can even be a liquid although dye lasers are not used in micromachining. The pumping source or energy input can be electrical such as a HV discharge in excimer lasers or Optical using laser diodes to pump Yag or fiber lasers. Lastly, all lasers need an optical feedback which consists of a mirror or high reflector and a partially reflective mirror, more about that later. A population inversion is critical to sustaining laser operation where a large number of atoms are in an excited state. Looking at the Energy Level Diagram, an electron is pumped to a highly excited state and transitions to a metastable region. The electron will seek its natural or ground state. However, it must release its energy and does so in the form of a photon.
Now we have atoms releasing photons in all directions or spontaneous emission. Similar to a blacklight which is a UV pump source and a fluorescent dye. The dye absorbs the UV wavelength and emits a visible color in all directions. In lasers, stimulated emission is achieved by the optical cavity. Photons bounce back and forth between the mirrors. As a photon passes an atom in an excited state, it too emits a photon creating a cascading or domino effect. The output coupler, being partially reflective, permits the laser beam to exit the cavity. The chart shows the laser types commonly used in micromanufacturing. Wavelengths can be anywhere from 193nm to 10.6 microns. Average power is typically in range of a few watts to a few hundred watts. Laser pulse duration can range from microseconds all the way down to femtoseconds which is a millionth of a millionth of a second.
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What's the true explanation, free from lies?
Complicated.
It would probably take a book.
Do you now understand why it's not going to be on the web?
It is on the web already.
Laser Fundamentals I-III | MIT Understanding Lasers and Fiberoptics
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Shaking molecules until Laser Light comes out. Building a Raman Laser!
In this episode, let's build a Raman Laser!
First I talk about some of the background of light scattering, Rayleigh Scattering, Raman Scattering discovered by C.V Raman, then the discovery of the Raman Laser by Gisela Eckhardt.
I cover the physical setup from an engineering standpoint.
An old Tattoo Laser I refurbished is used to pump a cuvette filled with a Raman Liquid.
Although in the early experiments the megawatt Laser energy destroyed the cuvette I was using, I built a Raman cell from scratch, with replaceable windows.
Do I manage to shift 532nm green light to 629nm Red?
0:00 Intro
0:15 Light Scattering
0:47 Rayleigh Scattering
1:22 Raman Scattering
2:26 Stimulated Raman Scattering SRS
3:14 Raman Laser development
4:19 Commercial Raman Lasers
5:14 Raman Laser Explanation
6:39 Intitial Experiment; Laser ate itself!
7:16 Raman Laser build
7:48 Raman Laser setup
9:41 First Light!
10:44 Measuring the wavelength
11:39 Conclusions and future work
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It is on the web already.
Can you let me know when the bit about supercontinuum lasers is please?
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It is on the web already.
Can you let me know when the bit about supercontinuum lasers is please?
DIY Supercontinuum Laser! The Ultimate White Light Laser!
In this episode I discuss Supercontinuum Lasers, the ultimate white light Laser! Normally such lasers cost thousands of dollars, but later on, I discuss constructing one from a practical standpoint, on a super tight budget using plain old telecoms fiber!
Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
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Did you deliberately miss the point?
When in these videos do they discuss supercontinuum lasers.
What's the true explanation, free from lies?
Complicated.
It would probably take a book.
Do you now understand why it's not going to be on the web?
It is on the web already.
Laser Fundamentals I-III | MIT Understanding Lasers and Fiberoptics
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Did you deliberately miss the point?
When in these videos do they discuss supercontinuum lasers.
It seems like you've honestly missed my point.
Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
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OK, let's try going back to the start.
You asked "
What's the true explanation, free from lies?
and I said
Complicated.
It would probably take a book.
Do you now understand why it's not going to be on the web?
And your assertion was
It is on the web already.
Well, if is then you should be able to show me the bit of that video where they avoid the lie about monochromatic light by discussing things like supercontinuum lasers.
So, once again,
At what point in the video you cited as evidence that there was a video that covered everything, did they cover supercontinuum lasers?
Or do you accept that the whole story- free from "lies we tell to children"- is complicated and will not be on YT?
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a video that covered everything
It's not a reasonable request.
"lies we tell to children"
Do you think that MIT's videos in my reply#14 also lies?
What's the true explanation, free from lies?
Complicated.
It would probably take a book.
Do you now understand why it's not going to be on the web?
It is on the web already.
Laser Fundamentals I-III | MIT Understanding Lasers and Fiberoptics
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It's not a reasonable request.
I know; That's why I told you it's
Complicated.
It would probably take a book.
Do you now understand why it's not going to be on the web?
So why did you claim to have one?
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Do you think that MIT's videos in my reply#14 also lies?
Do they say laser light is monochromatic?
Is it?
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Do you think that MIT's videos in my reply#14 also lies?
Do they say laser light is monochromatic?
Is it?
This is what he says at 7:30 in the first video.
property number one now some people refer to it as high monochromaticity
Googling for images of "laser spectrum" shows various shapes of curves.
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So that video repeats the "lies we tell to children" idea that all lasers are monochromatic.
So it is clearly not an example of
"the true explanation, free from lies?
So why did you say such an explanation was
on the web already.
And link to the video?
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So that video repeats the "lies we tell to children" idea that all lasers are monochromatic.
So it is clearly not an example of
"the true explanation, free from lies?
So why did you say such an explanation was
on the web already.
And link to the video?
Both of what you called lies and not lies are available on the internet. My problem is why tell the lies in the first place? What was expected to be improved by telling them?
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Most introductions of laser say that laser is a source of monochromatic light. This video shows polychromatic laser instead.
How many times have I explained the idea of "lies we tell to children"?
The whole body of knowledge about lasers is immense and complex.
Nearly all of them are practically monochromatic.
But not all of them.
Most of them are built in Fabry Perot resonators.
But not all of them.
And there are a stack of other complexities and exceptions.
If the "school level" explanations we gave in YT videos tried to include all the caveats and so on, the video would take days and nobody would watch it.
If you want a more detailed view, you need to plough through three hours of the MIT videos.
And even they don't cover everything.
So why did you say they did?
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The whole body of knowledge about lasers is immense and complex.
Nearly all of them are practically monochromatic.
But not all of them.
Most of them are built in Fabry Perot resonators.
But not all of them.
And there are a stack of other complexities and exceptions.
If the "school level" explanations we gave in YT videos tried to include all the caveats and so on, the video would take days and nobody would watch it.
If you want a more detailed view, you need to plough through three hours of the MIT videos.
And even they don't cover everything.
They can just say that most lasers are monochromatic, without saying that it's a defining characteristics of laser.
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They can just say that most lasers are monochromatic, without saying that it's a defining characteristics of laser.
For many applications, the monochromaticity is a requirement- it's the reason they use lasers.
You can always add these side notes and complications.
But it's likely to confuse newcomers.
I'm puzzled that you don't accept the general principle of teaching the broad basics first, and only teaching the details later- to those who need to know them.
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You can always add these side notes and complications.
But it's likely to confuse newcomers.
There's a difference between known unknown and unknown unknown. The latter will cause false confidence in one's own knowledge, and can cause unnecessary arguments.
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Fortunately, if you realise that you didn't really study the subject, but you just watched a few YT videos, you will be aware that you have many known unknowns.
Now we have that sorted out, can you answer this?
If you want a more detailed view, you need to plough through three hours of the MIT videos.
And even they don't cover everything.
So why did you say they did?
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Fortunately, if you realise that you didn't really study the subject, but you just watched a few YT videos, you will be aware that you have many known unknowns.
Thanks for the great advice, which also apply for yourself.
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Now we have that sorted out, can you answer this?
If you want a more detailed view, you need to plough through three hours of the MIT videos.
And even they don't cover everything.
So why did you say they did?
Did I say that?
It seems like you are misunderstanding my intention of posting their videos. I tried to show that even reputable sources can provide misleading information. You can't blindly trust them. Even they must be verified.
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Did I say that?
Yes, you did.
Here
It is on the web already.
Laser Fundamentals I-III | MIT Understanding Lasers and Fiberoptics
In response to me saying that the version without lies wouldn't be on the web.
It seems like you are misunderstanding my intention of posting their videos. I tried to show that even reputable sources can provide misleading information.
That's pretty much the opposite of what you said at the time.
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In response to me saying that the version without lies wouldn't be on the web.
What makes you think that it's not yet found on the web?
You can simply google it.
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You can simply google it.
You tried that, and it didn't go well, did it?
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I just googled for laser spectrum, and here are some good results.
https://www.newport.com/n/laser-types
(https://www.newport.com/mam/celum/celum_assets/Figure_17-Photonics_Handbook_800w.gif)
https://integratedoptics.com/spectral-properties-of-cw-lasers
(https://d2ayxbnjh6lipr.cloudfront.net/Products/spectra/Old/405nm_slm_laser_without_clean-up.jpg)
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I just googled for laser spectrum, and here are some good results.
Do you understand them?
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I just googled for laser spectrum, and here are some good results.
Do you understand them?
Not yet. Perhaps with more data I would. Just like this fascinating video.
INSIDE A LASER! An Open Cavity Helium-Neon Laser!
Let's take a look at an awesome open resonator cavity He-Ne Laser!
Tweak-able and hackable, you could fit your entire body inside the Laser cavity!
I talk about the Brewster angle, and the technical specs of a NOS Brewster windowed Helium Neon Laser tube!
Optical contacting is discussed, that is used to bond glass parts with no glue, but creates a permanent bond.
I designed built a really cool mirror mount that can hold 6 Laser mirrors!
I show how to do Quick and Easy Laser alignment, and demonstrate Transverse Electromagnetic Modes (TEM), as well as extend the cavity to around two feet!
Even if we can't understand it yet completely, let's just appreciate the information it contains. It will become part of training data for future AI models.
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It will become part of training data for future AI models.
What could possibly go wrong?
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(https://www.repairfaq.org/sam/onebrew1.gif)
https://www.repairfaq.org/sam/onebrewt.htm
I wondered where the light reflected by Brewster window goes.
(https://www.repairfaq.org/sam/dobtlas1.gif)
I'd like to see the demonstrations of this tandem setup. Can it show destructive and constructive interference?
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It will become part of training data for future AI models.
What could possibly go wrong?
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A lot. That's why AI safety becomes important.
Just like kids, AI models make mistakes, especially with incomplete data. But with lenough essons learned they can grow up to be more knowledgeable than their teachers.
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I wondered where the light reflected by Brewster window goes.
Did you wonder why they are called "Brewster windows"?
"Brewster's angle (also known as the polarization angle) is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection."
From
https://en.wikipedia.org/wiki/Brewster%27s_angle
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Can it show destructive and constructive interference?
Yes.
Longitudinal Modes
https://www.experimental-engineering.co.uk/helium-neon-lasers/theory-modes-coherence/
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I wondered where the light reflected by Brewster window goes.
Did you wonder why they are called "Brewster windows"?
"Brewster's angle (also known as the polarization angle) is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with no reflection."
From
https://en.wikipedia.org/wiki/Brewster%27s_angle
Let's compare our sources.
https://www.rp-photonics.com/brewster_windows.html
Brewster Windows
Definition: transparent plates which are oriented at Brewster's angle such that parasitic reflection losses are minimized.
An uncoated glass plate at normal incidence would normally have a reflectivity of several percent on each side. With an anti-reflection coating, this could be reduced to e.g. 0.2%. Brewster windows can have at least 10 times lower losses. In addition, any residual reflection will leave the resonator, rather than lead to interference effects (as can occur for windows with normal incidence). Of course, both Brewster windows in a setup as shown above must have exactly the same orientation.
Due to the significant loss difference between p and s polarization, the polarization of laser emission is usually forced to be in the p direction if a Brewster window or Brewster plate is within the laser resonator. In many lasers, this is the only effect determining the polarization direction.
A potential disadvantage of Brewster windows (or other polarizing optical elements) in a laser resonator is that large depolarization loss can arise if, e.g., thermal effects within a laser crystal affect the polarization. In that case, reflected beams with significant optical power and typically poor beam quality leave the Brewster windows.
As usual, perfect material are not common in nature.
The diagrams above clearly show where the light reflected by Brewster window goes.
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Light with the "wrong" polarisation is reflected out of the optical path and hits the casing of the laser (or of the lab, if you are running the laser without a case).
But, because it's lost from the laser it isn't amplified (much), so it's not a laser beam- it's just an expensive neon lamp.
The refractive index, and thus the Brewster angle depend on wavelength, so it may be possible to select the wavelength at which the laser operates by changing the window angle..
Obviously, that takes a more complex setup.
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2025 world's strongest handheld laser
0:00 intro
3:36 building the laser
6:07 powering it up
7:35 first burning tests
9:58 melting a penny
12:11 opening a bottle
13:38 the Gillette test
15:10 welding with the laser
17:05 making a ruby
19:52 burning tungsten
21:06 burning diamonds
24:05 difficulties and failures
26:22 flammable liquids
28:07 laser vs. ice
29:25 world record comments
32:31 laser safety
33:43 opera sponsored segment
This dude likes to take things to the extreme.
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The zinc oxide "frozen smoke" is called "philosopher's wool". It predates manmade lasers.