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LD Emitter Sizes - Please post your LD Data Sheets or findings here!

Alaskan

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As I get the information I will be adding posts to this thread giving the emitter sizes of the various laser diodes we use, this info is useful for calculating the expected divergence for a given beam width. Most LD data sheets do not provide this information but as suggested by RedCowboy, using a standard lens for which the divergence with a specific diode is known, we can back calculate the emitter size when taking its focal length into consideration along with the dimensions of the spot the beam produced in inches or preferably in millimeters at a distance.

I'm hoping others will help me gather this information, but many members are not interested in these figures. In any case, I will be adding to this thread as I can. If members have already determined the divergence of their laser pointer diode and could post the type of lens, lens diameter, its focal length (if known) and the size of the spot their laser pointer produces at a measured distance when at infinity focus, this information could also be used to extrapolate the approximate emitter size to add to a document I would like to put together listing as many diodes as I can. If you find the emitter size of any laser diode either through documentation, or other means, please post! If you have links to data sheets or specifications please post those here too.

Thank you to those who help with this, I will +rep you for the info when I can. If I could buy 10 reps to hand out to each member who supplies information I would! If someone has a good procedure to determine the emitter size of a diode or instructions for taking the measurements to determine divergence please share :)

Here's a link to a page I have been collecting low divergence laser diode data sheets:

http://imageevent.com/qdf_files/technicalgoodies/experimentersfolder/irandlightwavecommunications/laserdiodedatasheets/lowdivergencelaserdiodedatasheets

I will update this first post from time to time with the information I find online, or is provided by members.
 
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logsquared

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This is the equation I use to get a rough idea: Emitter size in (mm) = divergence(radians) X focal length of lens (mm)

The divergence is as measured after the collimation lens.

M140 diode for example: .0036rad X 4mm = .0144mm (14.4um)
 
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Alaskan

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Based on the divergence of the NDG7475's typical fast and slow axis of 35 & 5 degrees out of the diode prior to collimation, or a ratio of close to 4:1, on average, if that is the fast axis, then the other or slow axis should be about 56um. Concur? I think I'm looking at this correctly but not sure.

 
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logsquared

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Based on the divergence of the NDG7475's typical fast and slow axis of 35 & 5 degrees out of the diode prior to collimation, or a ratio of close to 4:1, on average, if that is the fast axis, then the other or slow axis should be about 56um. Concur? I think I'm looking at this correctly but not sure.

The Fast Axis is actually the smaller dimension of the emitter. So, for the M140 the ~14um dimension is the wider dimension and the Slow Axis. The height is much smaller... around 1 or 2 um. The emitter dimensions can't be calculated from the raw divergence numbers. A known lens is needed to calculate the emitter size. However, the Fast Axis always has the smaller emitter dimension. On some single modes the raw divergence of both axis can be close from what I have seen.

I can't remember what the m140 divergence is after the G2 lens(4mm Fl) in the Fast Axis. I know its about 3.6mrad for the slow axis. That's how I calculated the dimension in above post.
 

Alaskan

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My thought was if you knew one dimension; either the slow or the fast axis side, you could then determine the other dimension by the relative differences of the divergence of the other axis.
 




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