Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

Single Mode Diodes

Eidetical

Active member
Joined
May 14, 2022
Messages
191
Points
43
Did anyone mention coherence length for laser in an interferometer?
It needs to be as large as possible. Often with diode lasers, one may see fringes all the time and think the coherence length is very long. It's possible that it is really short, and just repeats at very short intervals. A holographic image featuring the "sliced bread" look is a good example of this.
 





kecked

0
Joined
Jun 18, 2012
Messages
929
Points
63
Measure small angles by putting a mirror on a string and bouncing the laser off it onto a wall. Put a small magnet on the back of the magnet and use a coil to make a magnetic field. Essentially a small motor. When you apply current the mirror should move. Now figure how to calibrate it…. Does the angle change linearly? If not what does that mean about the string?

put a polarizing filter over the laser and turn it so you see the brightest light. Now bounce this off surfaces and observe the beam through a second polarizer. Did the angle of the polarizer change? Is it still the same.

redo the double slit experiment.

observe scattering in water and other liquids.

lots to do.
 

Eidetical

Active member
Joined
May 14, 2022
Messages
191
Points
43
Here's a late-'60s interferometer set up with a late-80s He-Ne laser showing better fringes than the pic shows. My whole career has been about making fringes, and making them hold still to record them.

OTI-176 Setup.jpg
 
Joined
Jun 25, 2017
Messages
349
Points
63
Here's a late-'60s interferometer set up with a late-80s He-Ne laser showing better fringes than the pic shows. My whole career has been about making fringes, and making them hold still to record them.

View attachment 74734

So what's the insight here? You can make perfect fringes with a lightbulb ( double slit experiment ) Congratulations to your long experience, but I don't see any additional information here ( The fringes look very nice though)

Singlemode
 

Eidetical

Active member
Joined
May 14, 2022
Messages
191
Points
43
So what's the insight here? You can make perfect fringes with a lightbulb ( double slit experiment ) Congratulations to your long experience, but I don't see any additional information here ( The fringes look very nice though)

Singlemode
The OP said they sought a single mode laser to make an interferometer. I thought a pic of nice fringes on one might encourage him, or possibly her, probably going more for entertainment and/or education than insight. ;)

Of course there's "additional information". You're saying the additional information isn't insightful, right? Your opinion, no problem. I don't disagree. But isn't "insight", like beauty, in the eye of the beholder? 💡
 

kecked

0
Joined
Jun 18, 2012
Messages
929
Points
63
He was looking for things to do with a single mode laser. I forgot to add holography
 
Joined
Jun 25, 2017
Messages
349
Points
63
The OP said they sought a single mode laser to make an interferometer. I thought a pic of nice fringes on one might encourage him, or possibly her, probably going more for entertainment and/or education than insight. ;)


Nice from you. Lasers as intertaiment for a new laser fan is high priority.
Of course there's "additional information". You're saying the additional information isn't insightful,
Nope, every bit added to this forum is additional information. Insightful or not depends on the contact

Nope

Your opinion, no problem.
Of course there is no problem with a personal opinion.

I don't disagree. But isn't "insight", like beauty, in the eye of the beholder? 💡

This statement makes every content here completely up to the eye of the beholder. We can than post kittens again?


Singlemode
 

xavierjohn

New member
Joined
Dec 20, 2023
Messages
2
Points
1
smbom.com which belongs to SMYG LIMITED is a good choice for you. You can find the single module diodes you need there.
 




Top