How far can I pop a balloon?

[RedCowboy]

Okay so I noticed with my M462 I can power it up with just one 3.7V cell and it makes it low power mode and then I can power it up with two 3.7V cells and it puts it in high powered mode. Is this because the M462 is a multi-mode and the BDR-209 is single mode? I'm thinking I'm going to put this in a seriously tiny microbuild.

@HydroSean

No it's nothing to do with modes like a flashlight, both diodes are on or off, with 1 cell your 462 is just under driven.

Your 462 is likely using a SXD " Bucking " driver and needs a minimum of 6.8 volts to maintain it's set output, with 1 cell it's not putting out the full current.

The 405's driver is " Boosting " and set up to run on 1 cell, the 462's driver is set up for 2 cells, it has nothing to do with the diodes operational mode.

Multimode has a dominate center wavelength with less energetic side bars of the adjacent wavelengths.

Single modes are primarily one wavelength.

However

There is a technical definition: http://laserpointerforums.com/f54/single-mode-multi-mode-laser-diodes-53695.html#post755315

 

[HydroSean]

@HydroSean

No it's nothing to do with modes like a flashlight, both diodes are on or off, with 1 cell your 462 is just under driven.

Your 462 is likely using a SXD " Bucking " driver and needs a minimum of 6.8 volts to maintain it's set output, with 1 cell it's not putting out the full current.

The 405's driver is " Boosting " and set up to run on 1 cell, the 462's driver is set up for 2 cells, it has nothing to do with the diodes operational mode.

Multimode has a dominate center wavelength with less energetic side bars of the adjacent wavelengths.

Single modes are primarily one wavelength.

However

There is a technical definition: http://laserpointerforums.com/f54/single-mode-multi-mode-laser-diodes-53695.html#post755315

Thanks m8, I wish I could rep you again because you're one of the most helpful ppl on this forum. :thanks: I am going to get the BDR-209 from DTR and put it in the pocket mini chrome host from jayrob. I'll make a thread of the build too and show you guys

 

[diachi]

Okay so I noticed with my M462 I can power it up with just one 3.7V cell and it makes it low power mode and then I can power it up with two 3.7V cells and it puts it in high powered mode. Is this because the M462 is a multi-mode and the BDR-209 is single mode? I'm thinking I'm going to put this in a seriously tiny microbuild.

Multi-mode and single-mode refer to the output beam characteristics, not the electrical characteristics. Single-mode lasers emit a nice round beam with a Gaussian profile. Multi-mode lasers do not. That's drastically simplifying it mind you...

Single-mode on the left, multi-mode on the right.

Edit: RCB bet me to it.

 

[HydroSean]

Multi-mode and single-mode refer to the output beam characteristics, not the electrical characteristics. Single-mode lasers emit a nice round beam with a Gaussian profile. Multi-mode lasers do not.

Single-mode on the left, multi-mode on the right.

Hey this reminds me of my quantum mechanics class, great pictorial representation, you and redcowboy are both very helpful :beer: cheers

 

[RedCowboy]

Ahh so a 445 MM diode can never operate in Tem 00 mode, I knew that but did not think about why as far as mode.

I was thinkinking about the observable raw output and the bars next to the dominate center wavelength.

I wonder about using special filtering to get a cleaner beam and dot from our MM diodes, I know that last build that minimoto kobyashi posted had a round spot, it was still a very good looking beam, but some trimming had to be in play.

http://laserpointerforums.com/f40/c...on-linos-beam-expander-98495.html#post1440347

 

[diachi]

Ahh so a 445 MM diode can never operate in Tem 00 mode, I knew that but did not think about why as far as mode.

I was thinkinking about the observable raw output and the bars next to the dominate center wavelength.

Yep, the optical properties of the cavity don't allow those diodes to lase single-mode. Even if the beam is round, it doesn't necessarily mean that it's single-mode either - as you can see in the diagram I posted. The multi-mode beam is fairly round, but has lots of hot spots instead of a nice even Gaussian profile.

That post you linked does a good job of explaining why.

This page gives some further details and explains the difference between single-longitudinal-mode and single-transverse-mode operation.

https://www.rp-photonics.com/single_mode_operation.html

Also this goes into details about why you get different modes:

https://www.rp-photonics.com/resonator_modes.html

Love that website ... great source of knowledge.

 

[RedCowboy]

So this truly beautiful build posted by minimoto kobyashi must be clipping inside the round expander. I know that's how it works, because my most powerful builds at a distance make a tiny bar at distance with some splash, but to keep the bar short cylindrical correction of the aggressive diverging axis has to be used or it's an ever lengthening line, even if tiny it's a long line unless the aggressive axis is corrected.

SEE THREAD HERE >>> http://laserpointerforums.com/f40/c...on-linos-beam-expander-98495.html#post1440347