davidgdg
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I don't think this laser has been reviewed before.
It's a 100mw 640 nm DPSS handheld from Dragon Lasers. I was curious about this laser because I have been looking for a while for a shorter wavelength red with good beam specs. Unfortunately all the high powered 635s are multimode with horrible beam specs and they also quite pricey. So I was interested to see this laser on Dragon's website at a decent power and with good specs. I was suspicious about the DPSS claim, but Frank confirmed it to me by email, although he was unable to suppy any details on the doubling maths or the crystals.
Anyway, it's an unusual laser. I don't know of any other DPSS reds, so I thought I'd give it a go. The price was also fairly reasonable at just over US$ 300. Not cheap, but the wavelength compensates for the relatively low power (see below).
So, on to the review.
The host is not the standard CNI portable. It's a more streamlined package going under the "Spartan" label:
It doesn't have the standard CNI key lock or LED lights, but fortunately does use standard 18650s.
Beam spec is only fair for a DPSS. I measured a bit less than 2 mrad (which is a bit more than the advertised spec of < 1mrad) and about 3mm at the aperture. Certainly less good than my 657 custom built which, although only a DVD diode laser, has a much tighter beam at 1mm with barely 1mrad divergence. The difference is noticeable. The beam from the 657 is pencil tight and the spot looks much sharper at a distance than the 640. I'm not quite sure why this should be as I would have expected the 640, as a DPSS, to be at least as good as the 657 or even better. So in that respect a bit disappointing.
However, the real interest in this laser lies in the colour and apparent brightness. As always, it is hard to describe colours, but it is distinctly different from the 657. The 657 has no hint of orange. It is quite a deep red. The 640 on the other hand is a more vivid red, with just the slightest hint of scarlet. The difference is not huge to the naked eye, but the camera sees them quite differently:
The 657 is on the left. The 640 on the right.
The camera obviously does not capture the colours accurately, but it does a decent job with the relative brightness. The two spots are similar visually, with the 640 being perhaps slightly brighter. What is interesting is that the 640 is putting out 109mw, whereas the 657 is putting out 260mw. So you can see that the relatively small shift in wavelength produces a big change in apparent brightness, with the 640 being (crudely) two and a half times as bright.
The output from the 640 is nice and stable as you would expect, given the relatively low power and the very chunky host.
I tried some beamshots, but they were hopeless. However, I will add some when I get my fogger.
Overall impression of this laser is that it is an interesting buy both for wavelength freaks and for those who like to collect slightly unusual lasers. It also has the added advantage that it produces about as bright a red beam and spot as you can get in a portable at a reasonable price. Just a shame that the beam spec is not quite what I would have expected from a DPSS.
David
It's a 100mw 640 nm DPSS handheld from Dragon Lasers. I was curious about this laser because I have been looking for a while for a shorter wavelength red with good beam specs. Unfortunately all the high powered 635s are multimode with horrible beam specs and they also quite pricey. So I was interested to see this laser on Dragon's website at a decent power and with good specs. I was suspicious about the DPSS claim, but Frank confirmed it to me by email, although he was unable to suppy any details on the doubling maths or the crystals.
Anyway, it's an unusual laser. I don't know of any other DPSS reds, so I thought I'd give it a go. The price was also fairly reasonable at just over US$ 300. Not cheap, but the wavelength compensates for the relatively low power (see below).
So, on to the review.
The host is not the standard CNI portable. It's a more streamlined package going under the "Spartan" label:
It doesn't have the standard CNI key lock or LED lights, but fortunately does use standard 18650s.
Beam spec is only fair for a DPSS. I measured a bit less than 2 mrad (which is a bit more than the advertised spec of < 1mrad) and about 3mm at the aperture. Certainly less good than my 657 custom built which, although only a DVD diode laser, has a much tighter beam at 1mm with barely 1mrad divergence. The difference is noticeable. The beam from the 657 is pencil tight and the spot looks much sharper at a distance than the 640. I'm not quite sure why this should be as I would have expected the 640, as a DPSS, to be at least as good as the 657 or even better. So in that respect a bit disappointing.
However, the real interest in this laser lies in the colour and apparent brightness. As always, it is hard to describe colours, but it is distinctly different from the 657. The 657 has no hint of orange. It is quite a deep red. The 640 on the other hand is a more vivid red, with just the slightest hint of scarlet. The difference is not huge to the naked eye, but the camera sees them quite differently:
The 657 is on the left. The 640 on the right.
The camera obviously does not capture the colours accurately, but it does a decent job with the relative brightness. The two spots are similar visually, with the 640 being perhaps slightly brighter. What is interesting is that the 640 is putting out 109mw, whereas the 657 is putting out 260mw. So you can see that the relatively small shift in wavelength produces a big change in apparent brightness, with the 640 being (crudely) two and a half times as bright.
The output from the 640 is nice and stable as you would expect, given the relatively low power and the very chunky host.
I tried some beamshots, but they were hopeless. However, I will add some when I get my fogger.
Overall impression of this laser is that it is an interesting buy both for wavelength freaks and for those who like to collect slightly unusual lasers. It also has the added advantage that it produces about as bright a red beam and spot as you can get in a portable at a reasonable price. Just a shame that the beam spec is not quite what I would have expected from a DPSS.
David
