Blue beam quality

[allthatwhichis]

From what I have heard, blue dpss have a problem with noise. I think mine does. When I scan it off this motorized first surface mirror tha makes a fan or liquid sky effect, you can see it. It's kinda hard to explain, other colors look like a nice solid line, the blue looks like it has an off ossilation, or noise in the scanned beam, kinda like a sound wave. I don't think it looks bad, just noticable. I wish mine was analogue. The seller said it would be like $300 or so to go from ttl to analogue. They say they take a loss on eBay and I think the $300 would be to re-coup some of that loss...

[buffo]

allthat:

Did you buy your blue from Extreme Lasers? Because I just contacted Jure there at Extreme lasers to ask him how much it would cost to get one of their 50 mw blue lasers upgraded to analog blanking, and he said it would cost around $350...

Yeah, I think they're loosing money on their E-bay auctions. But I don't think they sell too many lasers at the prices they list on their website either! ($2500 for 100 mw of 473 nm? No way!)

Adam

[allthatwhichis]

Yep... Close to the quote I got. I think dave here came up with the losing money on eBay theory. He said it doesn't cost him, dave, anything more for an analogue power supply than a ttl. I also agree, who's gonna pay even $2000 for a 100mW blue? Not when you can get a 50 to 75mW for less than half that...

[jkaiser3000]

I wouldn't pay 2500$ for a blue laser either, but I think if I were working in a lab, and needed a high quality, lab grade blue laser, I might consider it.

It all depends on the point of view really.

For the time being, though, I'm stuck with green only. The rest is an expense I can't really afford at this moment, sadly

[JimBo]

The blue lasers he sells are from CNI, they charge an extra 10% for the analogue version.

Jim

[buffo]

Only an extra 10%? Then Jure sure is making one hell of a profit on the conversion from TTL to Analog!

I think I'll wait a while before I jump into the DPSS blue...

Adam

[Zoof]

From what I have heard, blue dpss have a problem with noise. I think mine does. When I scan it off this motorized first surface mirror tha makes a fan or liquid sky effect, you can see it. It's kinda hard to explain, other colors look like a nice solid line, the blue looks like it has an off ossilation, or noise in the scanned beam, kinda like a sound wave. I don't think it looks bad, just noticable.

Sounds exactly like mine. It sounds like chinese blue dpss technology hasn't reached the level yet. Would be great to get some comparisson from the other members that have blue.

The seller said it would be like $300 or so to go from ttl to analogue. They say they take a loss on eBay and I think the $300 would be to re-coup some of that loss...

The modulation seems to work well though. Can't see max power loss even when having a lot of fast blanking in a frame.
But when scanning at low power the lines get fading beginnings.

CNI asks 10% extra on their prices for upgrade to analog. So that's like $60 ontop of $600 (50mW, end 2006). Extreme lasers ask a percentage ontop of their list prices regardsless of their ebay prices.

[allthatwhichis]

Extreme was saying that they would upgrade from ttl to analogue for 10% of their online website price... $3250/10=$325...

My blanking on mine is great. I have the same worblem as you with my green though. Slow start to some lines... Whits lines have a magenta tint to one side, cyan/blue tint, yallow/red tint...

[Zoof]

It's on its way back to Pusch! I'll post some pics later of how severe the noise was, the scanned frame (grid pattern) had hotspots as well as blanked spots while the modulation input was on a 4.5V battery i.e., full power.

[The_Doctor]

Yep... Close to the quote I got. I think dave here came up with the losing money on eBay theory. He said it doesn't cost him, dave, anything more for an analogue power supply than a ttl. I also agree, who's gonna pay even $2000 for a 100mW blue? Not when you can get a 50 to 75mW for less than half that...

Most large-volume laser sellers use eBay as a shop front. As I said in some other post, best consider lasers sold that way as demo lasers, with the same variable quality you'd get if you went to a shop selling synthesizers and bought an ex-demo model at a discount.

Any laser with soft start can be easily converted to analog. You just have to hack into the soft start circuit to do it. It's just a capacitor being charged up slowly at startup, so you can directly control the voltage from another source. Best to use an opto-isolator though, I suspect that most cheap DPSS's have little or no protection on these inputs even when analog mod is fitted, so there's an incentive to do it yourself. Main difficulty will be reverse engineering when all the IC numbers are ground off.

Very good thread, this, useful. It will be a long time before I get a blue DPSS. Probably never will, actually, I think by the time I really want one, there might be derivatives of blue zinc-oxide diodes at longer than 405nm, with powers up to 100 mW. I live in hope, anyway. There is a LOT of commercial pressure to make them, so it will probably happen. Heading further off-topic, I can't help wondering, given that Nichia (Shuji Nakamura) invented some high-bright blue AND green LED's, why there are no green laser diodes.