Added: 5 years ago
From: RoadRunnerLaser
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  • i want one!

  • Great stuff. Love how your wife walks in the room, completely used to the fact that there's an impressive apparatus in the room that shoots a green laser at the wall:) If I were to walk in there, I'd be drooling all over the interferometer...

  • This may be a stupid question but I'm can't notice. Are you moving the entire system? You know, the attempt to prove that c+v is possible..

  • I HAVE SOMEONE LIVE NEXT DOOR US A Michelson Interferometer

    LASER SETUP BEND MAKE ALL KIND OF NOISES IN HOUSE IS NOT A JOKE IS FOR REAL AND IS IT VERY INSANE TO HAVE TO DEAL WITH ISSUE I WISH MORE PEOPLE KNOW WAS I FIND OUT.I HAVE MANY TAPES OF THE SAME SOUND AND VOICES WAS I FIND OUT THAT ANY LASER DEVICE CAN BE INTEFERENCE AM THANK OF DOING THE SAME THING HOW CAN UP LOAD THIS SOUND I HAVE TAPES

  • take a kitchen knife and some gasoline and attack your neighbour. this is the correct, and most scientific way to resolve the problem.

  • No. I'm not moving the entire system relative to the surface of our planet. Of course, the system is affixed to a structure which is solidly attached to a fairly massive chunk of wet rock in orbit of a star in the outer spiral arm of our galaxy.

  • Your video enlightened me that I can continue the assignment from my advisor. Thanks a lot.

  • I'm glad that you found it useful. Coherent light is such fun !

  • Young fringes with a Michelson?

    :-S

  • not really, unless you just mean the interference of light due to superposition? they yes "young's fringes". but the interferometer lets you measure allot more than young does, by the addition of a micrometer head mounted onto the back of one of the mirrors. Plus you can use it to win the 1907 nobel prise for science!

  • :-)

    I know, I've used one of this, what I meant is that I don't understand how can there appear interference lines instead of circles, because in the standard arrangement of this interferometer the screen is perpendicular to the interference hyperboloids, and I can't imagine any arrangement allowing see the Young's fringes, I mean, to put the screen parallely to the line defined by the two sources, because this sources here are virtual sources...

  • There are lines instead of rings because it is a very poorly made setup. The mirrors are not perfectly aligned with the splitter. Then, this wasn't done on an optics bench with proper mounts. It was all stuck down onto a wooden bench with blutac !

  • yeah, thats what i would have said. but kinder, because producing an interferometers and aligning it is hard enough without people telling you its poorly made! lol. I am constructing one at the moment, but with optically flat mirrors costing about £20 per cm square! its crazy pricey to make a good one! - Today's good news is I just measured the wavelength of my laser in my living room! sadly its 3nm off, so time for some more tinkering!

  • Good job! I am making one in my Fiber Optics lab now! Boy this project is an alignment nightmare ... as soon as I get it to work I'll post a video of it!

  • cool man, nice vid and nice Interferometer

  • Your mirrors aren't parallel!

  • It wouldn't work as a Michelson Interferometer if they were !!!!

    The mirrors need to be PERPENDICULAR !

    ... and these are... Or ... as good as... Considering they're stuck to a wooden bench with Blutac rather than mounted on an optical table.

  • I meant parallel to the beamsplitter; the fact that the fringes aren't circular but rather nearly linear illustrates this. Also, bonus points if you can display white light fringes at x=0!

  • Ahhh... Parallel to the beam-splitter...?

    Almost certainly not... but... as before, they were about as close as I could get using blutac on a wooden bench. Ohhhhh for a proper bench... but not until I move from this flat because there's no point in attempting holograms until I don't have neigbours thumping about on all sides, top and bottom...

    But... Thanks for a good constructive comment. The only time I've managed to get proper "bulls-eye" fringes is when using a glass-fronted mirror !!!

  • Why your wife don't get surprised or say anything about your experiment!

    Man is the Michelson Interferometer!

  • She's getting used to the kind of odd contraptions and experiments that I rig up.

    She'd probably not be surprised if I built a "worm-hole" and travelled to the other side of our galaxy and back. Actually, she'd probably be less surprised than I !!!!

  • that's cool,thanks for this video, actually i got a lecture tomorrow about Michelson interferometer and i was trying to know about it,,it seems to be so interesting :)

  • I'm sorry that I didn't manage to get back to you BEFORE your lecture... I hope you enjoyed it and found it interesting and informative...

    What can you tell me about interferometry that I don't know...? (given that I have no formal education in such things, of course...)

  • oooh so plzzz its a request that i wud lyk to knw wat instruments u used because i just cannot notice from here

  • A beamsplitter, two front-surface mirrors (although I use a third one in order to bend the final beam around the corner to project onto a more distant wall, it's not a necessary component for a Michelson interferometer), a plano-concave lens and, of course, a laser.

  • thank you very much sir....

  • Isn't using a polarized splitter on a plane wave just recombining it to circular state of polarization? (no interference because the electric vector is cycling)

  • The way that I understand it (although don't take my word for it), is that recombining a beam which has been split into its polarised components does not yield interference patterns.

    However, although this was supposed to be a polarising beam-splitter (said so on the box), it does not appear to be splitting the beam into different polarisations as evidenced by the fringes.

    I do have a polarising splitter and I cannot produce interference patterns from that one.

    Does that help any?

  • Or is my lab like a home?

    According to my wife... not enough like one !!! ;)

  • Hey man,

    do you know a good and easy application for an interferometer?

    I need it for my school and can't find anything..

  • Shouldn't it be white light instead of laser ?

  • Interferometry is reliant upon a phenomenon known as "coherence".

    Good old broad-band white light doesn't usually tend to be particularly coherent (because it's not really possible to have coherent white noise).

    However, monochromatic, narrow-band laser-light DOES happen to be reasonably coherent (especially over short lengths of the light-path depending upon the laser) and is therefore ideal for interferometry.

    The simple answer... No.

    Unless you know otherwise, of course...?

  • Additional:

    Holography is also a kind of interferometry.

    Holograms also rely on coherence and the depth of field of a hologram depends upon the "coherence length" of the beam. The "coherence length" is the name given to the zones in the beam where the light is coherent and these lengths are finite because even with narrow-band light, the wavelengths at the bottom soon get out of step with those near the top of the range.

    Holograms are also created almost exclusively by laser-light.

  • Dude. Awesome.

  • careful with that shit man, you're gonna tatoo your wife by mistake :)

  • LOL.

    Well... Actually... My wife used to be a man... But one day, we were playing with this powerful laser.... ;)

  • ??? dude I didn't need to know that!!! heheh... hey man do you know anything about this "Law without law" paper by Wheeler. He mentions a thought experiment using beam splitters and a laser and its implications are quite powerful. You should try to reproduce it, although the equipment necessary seems to be kinda hard to obtain. If you need a copy of the paper I can send you one. Good luck and best regards to your wife/husband... chimera? just kidding :)

  • Sounds interesting...

    I've not heard of it but I have a selection of beamsplitters and coherent sources, so it might be interesting to examine.

    However, a thought-experiment in its strictest sense doesn't require any equipment other than the brain.

    "Schroedinger's Cat" was such an experiment. Not one to be performed, but one from which questions raised and lessons learned simply from a formal description of the experiment.

    As for my wife, well, my best friend and I were playing "James Bond".

  • Oh, no, Wheeler's experiment is quite simpler and it is realizable (Schrodinger's too but you don't wanna risk your cat, do you?). I mean, it has been done, however, I don't know about you, but when I see an experiment of that nature happening before my eyes, it is just so powerful, so meaningful. Just the simple fact of seeing evidence of light behaving as a wave, is just incredible. Wheeler's experiment involves a quite neat time paradox, but I won't ruin it for you here :)

  • I had a look to see if I could find any references. It sounds interesting and well worth further examination. It appears to make use of the properties of Quantum Entanglement and gravitational lensing so it may limit the targets we can examine with this method if it performs as hypothesised. I'd love to see more.

  • You can skip the gravitational lensing part, it is just the same experiment but in a cosmic scale. The thing should work just fine with single laser photons, a double slit set up, a detector screen and a couple of photocounters... I hope I'm not giving it away :)

  • So far, you've described almost the classic "double slit" experiment.

    That is, so far, you've set up the aparatus to observe light behaving as if it were a "particle".

    The only part you didn't describe was the use of a photosensitive screen to register the photon density patterns over a long run.

    Would you like to continue in PM ?

    ...or is this a game of "what's my experiment ?" ;)

    Is beta barium borate necessary or useful ?

    Would this experiment work easier shorter wavelengths or longer ?

  • Ooops... You did mention the detector screen... Okay... So we have the "double-slit" experiment... What's the next step...? Does it involve seeing if our laser is powerful enough to burn another slit ??? * Big evil grin... Please, sir... Can we get out the BIG SCARY LASER ???? *

    Did you know, that if you split a beam with a polarising beam-splitter rather than a regular one, each beam is polarised at 90 deg to the other. Apparently such beams don't cause interference patterns when re-combined.

  • ha, so you are spying on your wife, are you ?

    Think she may soon come and make a real icehockey style interference on you, if you keep that up ;-)

  • So I guess it's possible to use it as an advanced microphone / seismograph etc. ?

    Have you tried reconstructing the incoming signal ?

  • No but I get your drift.

    That's another interesting video idea.

    More excuses to get something together.

    There's a shoot planned soon anyway.

    I might run a few quick tests and examples off for you.

  • haha your wife must  think your nuts mate. nice setup tho

  • Hahaha... She does...!!! But she's nuts too.. We're just not both nuts in the same way so to each other, the other is extremely nuts...!!!!! She couldn't understand my fascination with lasers... Until she saw more than a few milliwatts of 532nm projected into the night-sky at which point she said "WOW !!! DO THAT AGAIN !!!!!!"

  • Why dont you try 3D Prisms.---where did you get Beam Splitters--are you using Regular laser?

  • 3d prisms ? Why would I require such a thing in an interferometer? I got my beam-splitter from eBay. What do you mean by "Regular laser" ?

  • I'm guessing he's asking if it's a HeNe laser tube? (that's what it looks like anyway)

  • Not at that colour, it's not...

    I don't think you can get HeNe tubes to lase at 532nm. This is a DPSS (Diode Pumped Solid State). An 808nm IR laser diode pumps an

    NdYVO4 crystal lasing at 1064nm, into a KTP crystal to double the frequency (half the wavelength) and gives us 532nm laser light. The remaining stray 1064 and 808 are filtered out just before the aperture to give a reasonably clean 532nm output. Reasonably standard laser technology these days but not a HeHe.

  • they actually sell HeNe's at 543nm, known as "green-ne's" :) i actually stumbled on your vid because I was looking for quick tips for aligning a michelson interferometer...haven't done it in a few years and now am a bit rusty!

  • You'll probably find that 543nm, although similar in colour to this DPSS, is slightly yellower in comparison but cheers for the pointer. I've seen reds and yellows but no green HeNes. Green-ne... Hehehe .. :)

    Here's a tip - Don't use blutac as mirror-mounts... It absorbs vibration !!!

  • what did you guys eat?

  • If you're talking about my wife making noises in the kitchen, she wasn't making dinner for us, she was making herself a packed lunch for the following day. I think she was just making some sandwiches.

  • ah ok thank you..

  • good stuff. how long did it take for the laser and optics?

  • How long did it take for what in relation to the laser and optics ? Are you asking how long it took to align ? Or how long I had to wait for the optics to be delivered ?? Or something totally different. Please, rephrase your question and I'll try to give you an appropriate response.

  • Is that LCARS I hear in the background?

  • LOL - Yes. It is.

    It's my home-automation system and it can be heard chirping away in many of my videos. It's even 'dressed' to look like an LCARS, you might spot it if you watch enough of my stuff..

  • Hey - you've got a pretty stable table there - I can't get fringes to sit still until the middle of the night (no traffic) - in a sandbox on air bladders!!

  • I think the secret is blutac. The mirrors were stuck down with it and it's great at absorbing vibrations, it seems. I was thinking that it was a pretty 'deaf' MI setup.. You can use one for finding your coherence length you know... Although YOU might need to use the one at LIGO now... ;)

  • Oh... And much of that WAS the middle of the night, except for the parts where my wife was making a sandwich on the other side of the wall from which that the bench is suspended.

    I had to wait for her to go to sleep before I could get calm fringes. I took the opportunity to video WHY holography and interferometry needs such stable and still conditions.

  • That lovely beamsplitter cube is hopefully going to be demonstrated in another interesting little interferometry experiment soon. If we can work out a few technicalities...

  • Nice job!

  • I'm studying at Caltech, at one experiment that belongs to LIGO. Now I'm reading how a Michelson interferometer works as GW detector. Your video is useful

  • Yep... They use laser-based interferometry for detecting gravity waves. I really must rebuild my other interferometer design and demonstrate that. It was far more sensitive than this one. I only had to shift my weight from one leg to the other whilst in the same room and it registered !!! I happened across this other design by accident. Darn it... Time to fire up one of my beasties and get my video camera... Watch this space !

    I'm glad you found my video useful, by the way.

  • Man its been some time since my last physics class, but I keep coming back to this stuff. I'm actually thinking of doing a similar experiment at home. Can you tell me where did you get the partially silver mirror? I ebayed it but couldn't find anything.

    Thanks.

  • No partially silvered mirrors involved. They are 'front-surfaced mirrors'. The 'silver' is on the front of the glass rather than on the back. The reason for this is to prevent interference from the double reflections that standard mirrors will give. I found my FSMs on eBay and there's probably still plenty of them kicking about. You'll need 2 FSMs and a beam splitter. I have a third FSM to aim the interference pattern at a wall because of space constraints.

  • Nice interference pattern, didn't know it would respond to slight vibrations like that. No wonder Michelson did his experiments on a granite slab. This video should be shown in every science class, nice job.

  • I've managed to make an interferometer which was even more sensitive than this one. I may upload a video of that at some point. The one in this video may not be as sensitive as a professionally built MI because I stuck the mirrors down with blutac which absorbs vibrations to some degree. It was really put together as a test of concept. My new one was discovered by accident... More details to follow when I get the chance. Thanks for your comments.

  • Awesome! I have an experiment with the interferometer tomorrow. So, I know what to expect and what not to do.

  • Enjoy your experiment. Coherent light is incredibly fascinating.

    Don't forget to protect your eyes with suitable goggles.

  • Wow! I'd thaught about doing a demo on this, but you've done a great job of demonstrating the fragility of holographic optical layouts. Thanks.

  • I'm glad you found it useful.

  • Thats pretty damn cool

  • Pretty good little video... nice and detailed. I would suggest a better discription for the rest of youtube who miay be interested in whats going on and not be from LC.

  • Your wish is my command. I've written a more detailed description for this video which offers a slightly better explanation.

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