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Feedback on Laser Video

XM360

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Hello all,

I wanted to pass another video by the LPF experts for comments and feedback regarding accuracy of information. Everyone was extremely helpful in providing feedback on my previous video explaining wavelength.

This video explains DPSS vs Direct Diode. My hope for the video is that it clears up any confusion or questions from folks that are completely new to the hobby and see the two terms used when shopping for a laser. Please let me know your thoughts if you have the time. Thanks!

Here is the draft video:
 



Lifetime17

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Hi XM,
Thanks for posting this informative video , as most of us here at LPF know about the difference between the two sources.
But it was great to watch the video
Rich:)
 

Snecho

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Great idea XM. The video is pretty good, however around 1:36 you mention something about "so you may be wondering why all consumer lasers are direct diode considering the [difficulties of DPSS]...

I feel like you misspoke there as that seems like an oxymoron and is confusing. I wasn't sure of the point you were trying to get across.

The only other thing I would consider is adding a section talking about the differences between the divergence of diodes vs DPSS and how DPSS is superior in that it's usually a tight TEM00 beam. Grouping and adding to the instabilities of DPSS in this section would also be a good addition I think.
 

gazer101

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Good stuff! The only issue I see is that you mentioned that the visible spectrum is from 400-700nm when in fact it should be from 380-740nm. Thanks for giving us early access to your vids
 

Cyparagon

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It's not that binary, gazer. To say 740nm is visible, but 741nm is invisible demonstrates a misunderstanding of the Gaussian eye sensitivity.

400-700 is an often quoted range. It's good enough for an intro.
 

gazer101

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It's not that binary, gazer. To say 740nm is visible, but 741nm is invisible demonstrates a misunderstanding of the Gaussian eye sensitivity.

400-700 is an often quoted range. It's good enough for an intro.
Just out of curiosity, what is the actual average visible frequency range for the human eye?
 

hakzaw1

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not the same for all eyes--duh--of course ..for eyes ''of humans''
 
Last edited:

Gianakakis

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Hello all,

I wanted to pass another video by the LPF experts for comments and feedback regarding accuracy of information. Everyone was extremely helpful in providing feedback on my previous video explaining wavelength.

This video explains DPSS vs Direct Diode. My hope for the video is that it clears up any confusion or questions from folks that are completely new to the hobby and see the two terms used when shopping for a laser. Please let me know your thoughts if you have the time. Thanks!

Here is the draft video:
Also when you look at it a DPSS Green laser is not really so inefficient compared to a directly green-emitting LD. Green LDs hover in the 15%-20% efficiency range. And because the IR pump diodes themselves are about 50-55% efficient in terms of green producing dpss lasers the dpss ones are more efficient overall at producing green. I say that you pick another wavelength of dpss to use as an example like 473nm or 589nm cause those are typically much less efficient than the green dpss lasers.
 

Snecho

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Hi XM,
Thanks for posting this informative video , as most of us here at LPF know about the difference between the two sources.
But it was great to watch the video
Rich:)
I believe the point was to peer review the video for YouTube.
 

XM360

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Great idea XM. The video is pretty good, however around 1:36 you mention something about "so you may be wondering why all consumer lasers are direct diode considering the [difficulties of DPSS]...

I feel like you misspoke there as that seems like an oxymoron and is confusing. I wasn't sure of the point you were trying to get across.

The only other thing I would consider is adding a section talking about the differences between the divergence of diodes vs DPSS and how DPSS is superior in that it's usually a tight TEM00 beam. Grouping and adding to the instabilities of DPSS in this section would also be a good addition I think.
Cleared up that sentence a bit

Also when you look at it a DPSS Green laser is not really so inefficient compared to a directly green-emitting LD. Green LDs hover in the 15%-20% efficiency range. And because the IR pump diodes themselves are about 50-55% efficient in terms of green producing dpss lasers the dpss ones are more efficient overall at producing green. I say that you pick another wavelength of dpss to use as an example like 473nm or 589nm cause those are typically much less efficient than the green dpss lasers.
Referenced the DPSS blues and yellows instead, thanks!

See the latest draft below:
 

XM360

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If nobody has any further remarks, I’ll move forward with publishing. Thanks for all the awesome feedback!
 

Snecho

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If nobody has any further remarks, I’ll move forward with publishing. Thanks for all the awesome feedback!
I still think it would be important to tall about that DPSS is much beam in beam quality with Gaussian beam characteristics and TEM00 and whatnot, but whatever you decide I support you. It's a great informative video that would be really easy to link for a newbie.
 

XM360

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I still think it would be important to tall about that DPSS is much beam in beam quality with Gaussian beam characteristics and TEM00 and whatnot, but whatever you decide I support you. It's a great informative video that would be really easy to link for a newbie.
The only reason I strayed away from that is because of how widely the beam specs can vary from laser to laser. I have some low-powered direct diode lasers that are close rivals to my DPSS units in terms of beam quality, while others aren't even close
 

Snecho

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The only reason I strayed away from that is because of how widely the beam specs can vary from laser to laser. I have some low-powered direct diode lasers that are close rivals to my DPSS units in terms of beam quality, while others aren't even close
I still think it's worth mentioning because, I mean, you get a diode laser and 90% of the time it inherently will have a bar shaped output or something that will need to be corrected by a lens. Just a cheap 532nm laser 303 from еBay will have a very nice, truly tight beam due to DPSS, which are super common.
 




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