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Re: PERMANENT THREAD: Ebay& other internet FINDS of interest- read all the OP please
Seems a good deal to me, even if a bit less output power:
https://sites.google.com/site/dtrlpf/home/diodes/nugm02-900mw-520nm-laser-diode
Newbies, these diodes do not have low divergence like a 532 nm DPSS laser! The beam spreads out fairly quickly compared to DPSS and due to that won't put a spot on the bottom of a high cloud like a DPSS laser can do, the output beam looks normal for the first 50 feet but after that you can see it is beginning to turn into a wide bar, or what I call a rake 500 feet or more away. However, if you use a 3X beam expander with them the divergence can be reduced to about what can be had with a DPSS laser pointer, use a 10X beam expander then this diode will have lower divergence than a DPSS can produce without an expander.
Another minus for these diodes compared to a DPSS laser is the beam has a rectangle shape, regardless of expanding the beam the ratio between the fast and slow axis remains the same and you get a rectangled output. If using a beam expander that doesn't bother me at all, but some members like to use beam correction with a pair of cylinder lenses to change the beam shape into more of a square output.
Here's a link to a cylinder pair some members have used with these diodes, these produce 2X correction, this diode really needs closer to 3X, but good enough:
http://optlasers.com/en/cylindrical...es-520-nm-with-brass-mount-5902693110200.html
Not sure the amount of correction used for these photo's, but this demonstrates what can be done with a cylinder pair to square up the beam shape:
Cylinder pairs act like a beam expander, in fact are beam expanders, but for just one side of the beam to widen the thin side of the beam profile. The beam will still expand at a faster rate than a normal DPSS laser does, but reduce the amount of expansion to one side, or one polarity of the output as well as make the beam a square shape, instead of a rectangle. To finish the job, a regular beam expander which expands all sides of the beam equally is needed, then you can have a laser pointer which is more stable than DPSS, with as good or better the divergence. Only draw back is increased cost for the additional optics, added loss as well as a fat beam, instead of a thin beam typical of DPSS lasers.
I don't believe it is necessary to square up the rectangle shaped output of these laser diodes, doing so adds more loss, but also would give the best overall divergence because when expanding the thin side of the rectangle to square it up, the divergence of the expanded side is further reduced by the ratio of the expansion.
Here's a link to a fairly inexpensive 3 X beam expander which can be used without beam correction ahead of it, designed to thread directly onto a laser pointer lens assembly barrel such as the G2:
https://www.sanwulasers.org/product/x3beamexpander
Several members have been working with this expander and have fabricated adapters to hold the unit firmly in place instead of hanging on the tiny lens assembly which is a bit wobbly or unstable.
Seems a good deal to me, even if a bit less output power:
https://sites.google.com/site/dtrlpf/home/diodes/nugm02-900mw-520nm-laser-diode
Newbies, these diodes do not have low divergence like a 532 nm DPSS laser! The beam spreads out fairly quickly compared to DPSS and due to that won't put a spot on the bottom of a high cloud like a DPSS laser can do, the output beam looks normal for the first 50 feet but after that you can see it is beginning to turn into a wide bar, or what I call a rake 500 feet or more away. However, if you use a 3X beam expander with them the divergence can be reduced to about what can be had with a DPSS laser pointer, use a 10X beam expander then this diode will have lower divergence than a DPSS can produce without an expander.
Another minus for these diodes compared to a DPSS laser is the beam has a rectangle shape, regardless of expanding the beam the ratio between the fast and slow axis remains the same and you get a rectangled output. If using a beam expander that doesn't bother me at all, but some members like to use beam correction with a pair of cylinder lenses to change the beam shape into more of a square output.
Here's a link to a cylinder pair some members have used with these diodes, these produce 2X correction, this diode really needs closer to 3X, but good enough:
http://optlasers.com/en/cylindrical...es-520-nm-with-brass-mount-5902693110200.html
Not sure the amount of correction used for these photo's, but this demonstrates what can be done with a cylinder pair to square up the beam shape:
Cylinder pairs act like a beam expander, in fact are beam expanders, but for just one side of the beam to widen the thin side of the beam profile. The beam will still expand at a faster rate than a normal DPSS laser does, but reduce the amount of expansion to one side, or one polarity of the output as well as make the beam a square shape, instead of a rectangle. To finish the job, a regular beam expander which expands all sides of the beam equally is needed, then you can have a laser pointer which is more stable than DPSS, with as good or better the divergence. Only draw back is increased cost for the additional optics, added loss as well as a fat beam, instead of a thin beam typical of DPSS lasers.
I don't believe it is necessary to square up the rectangle shaped output of these laser diodes, doing so adds more loss, but also would give the best overall divergence because when expanding the thin side of the rectangle to square it up, the divergence of the expanded side is further reduced by the ratio of the expansion.
Here's a link to a fairly inexpensive 3 X beam expander which can be used without beam correction ahead of it, designed to thread directly onto a laser pointer lens assembly barrel such as the G2:
https://www.sanwulasers.org/product/x3beamexpander
Several members have been working with this expander and have fabricated adapters to hold the unit firmly in place instead of hanging on the tiny lens assembly which is a bit wobbly or unstable.
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