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Review: 50mW o-like blue


New member
Nov 7, 2008
In single-diode high-powered red lasers, usually 300mW and above, the diodes are "multimode". What this means is that instead of a diode with just one emission region (like DVD diodes) you have a diode with multiple emission regions. This allows a single diode to output far more power than a single-mode diode ever could, but this comes at the cost of beam quality. Here's what the output of a multimode red looks like:

(thanks FrothyChimp for the pic)

The beam in this picture has been enlarged by running it through a lens in order to show detail.

These kinds of lasers typically have a larger beam diameter than most other lasers (mine is 6mm at the aperture), and so they won't always fit completely on the galvo mirrors. Also, typically the divergence is not too great with multimode diodes, but in my case CNI seems to have done a very good job of collimating my system. The divergence is well under 2 mrad.

You're actually using a system that will give you a cleaner beam than most of the high-power diode-based 650nm systems that are commercially available. I'd stick with it as long as possible.

Some folks use DPSS red (671nm) instead of 650nm because DPSS always provides a very thin clean beam compared to diodes but since the wavelength is so long a 671nm laser is generally only about 1/3 as visible as 650nm.
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