a bunch of questions about greenies, and misc

i'v been reading here for 2 weeks since i found you, and left with a few questions that got too many search results, atm my questions are scattered across my mind over a period of 1 week so their relative order is random.

1:
what happened to the market, in 2006 there was a huge hype around wicked lasers, they charged for pen sized 100mw 300$ +, they had their green spyder I and II 200mw for 1600$, now overall prices fell 3 times and i don't see any remnants of green spyders except the arctic 3 blue and dirt cheap relative to their past prices.
while other companies like optotronics, nova lasers and dragon lasers barely budged.

component prices: after i dissected my viper 95, then watched a bunch of youtube vids and red a lot info here, i got confused about actual parts prices.
like fore example i paid 200$ for my 95mw while rayfoss and O-like sells same "advertised" power for 3 times less and 200mw for a bit over 100$.

i go check bare module prices for 100mw and it's even lower, then i check KTP crystal prices on O-like for 200mw green 2x2x5 14$, i look at my viper crystal which looks 1.5x1.5.cant measure depth, and think "something is wrong here".

even if i calculate by end user prices, driver 15$, 808nm 500mw diode 10-20$, KTP crystal less than 14$ because it's smaller for pumping 100mw green out of it the than the intended crystal for 200mw, glass lenses 10-15$, module 10$, total 70$-ish, is that about it ?

surely for a company it's even cheaper by the quantity they buy.

2: so when i see a green 150mw-200mw module diode with driver and lenses in the area of 100$, what chance it'll have powerful enough diode and appropriate crystal for the advertised rating and not overpowered wimpy parts that'll die faster ?

3: what shape of KTP crystal is better, short cavity 3x3x2 or prolonged cavity 3x3x5 ? (when the 3x3 is the entrance perpendicular to the beam)

4: lasers that have focusable lens for burning, when set back to normal infinite beam, do they stop influencing the beam and go back to same divergence as that module would be without the focusable lens ?

5: i noticed some new life span for diodes with 3500 working hours popping on eBay, what the heck is that ? (few weeks ago those same sellers wrote 5000-6000h)

6: is most of the heat produced coming from the tiny itsy bitsy diode or KTP as well ?

7: when continuing to run a laser in hoped mode (split beam) does the diode or KTP get damaged ?

my viper after doing the 1st hop mode ever because it was a bit cold, around 16c, later on just got more frequent hops even when temps were above 20c, i couldn't conclude anything final from this. (it happened with all 3 vipers, and with more use got worser and worser, 1st vipers beam held the longest)

8: why green lasers considered very sensible to shock ? (i do see the 3 thin wires connected to the diode that look like potentially the weakest link, but the way they sit on the mount wont make them rip or budge on drops, maybe the mount itself can twist a bit around the screw but no short circuits or so)

9: why 445nm starts with such a fat beam diameter of 5mm, is that some physical property ? (that's the info i stumbled upon around here, but in 2-3 words)

10: i saw on eBay some drivers have the LM358 regulator, is that boost ? probably not a buk otherwise my viper wouldn't burn from a 3.2v bat, or buk are considered even when stated 3-4.2v can be used, so even the little drop from 4.2v to 3.5 or what ever 808nm diode eats needs a buk ?

11: is there really any big difference in quality of the parts sold by O-like rayfoss and others i wont mention that sell 2.5-3 times more, except the quality control filtering the under spec ones ?

the big picture i get is that company A will have a constant % of units sold within advertised spec while company B will have more under spec, but the ones that are good from company B are equal to companies A units, or there's more ? (without considering consumer support and good communication).

and i aint talking about something dragon lasers do, taking 20mw laser and sell it as 50mw because it can output so, that is just despicable. (at least their honest)

damn it, i was clicking for few hours all of this from my phone yesterday and the memory got full and i couldn't post it.

i probably forgot something along the way,
thanks for any answers ! :yh:

The laser pointer market has undergone serious changes. Some types of diodes like the ones in the popular 1 Watt blue pointers were taken out of C@sio projectors and then sold for cheap. Green pointers are also mass produced and being alot cheaper.

With prices for laser pointers, you also need to factor in the cost of the host, heatsink, labor as well as the diode, driver etc.

Also the main reason why green lasers are so sensitive to shock, (according to what I have read) is that the crystals can sometimes be dislodged and move around.

much appriciate the answers guys.

i wonder if i asked too many questions at once, or some are stupid or the 100th time same question, some feedback if to rephrase any of the questions ?

well i assume the answer to 9 is, yes a property.
3 is probably prolonged shape, that's what their prices imply.
5 i assume overpowered wimpy parts so their lifespan is cut by half.
but assuming is not knowing, so i look for confirmation.

comm ooon people somebody here knows a bit of other stuff, spiiiiill the beans.

1: As production volumes increase, prices always go down. However quality goes down as well. To make a quality reliable and durable laser takes considerably more time and a more complicated manufacturing process than cranking out thousands. You'll notice that most of the companies selling lasers at a premium, also have reputations for good quality and support. Though there are a few that try to peddle junk for inflated prices as well, but those usually get exposed quick enough..

There are also some parts your forgetting about. Green DPSS lasers use two crystals, only in cheap lasers they're usually bonded together. One is ND:YAG or ND:YVO4 for the 808nm to 1064nm conversion, and the second is KTP, which doubles the 1064nm to 532nm. Two other necessary components are HR and OC mirrors to form the optical cavity. In cheap lasers the HR is a coating on the pump side of the ND:YVO4, in higher quality lasers it's usually a separate optic. The OC mirror is usually a coating on the output lens in front of the output of the crystal set in virtually all greens. You'll also usually have a collimation lens in addition to that as well. On the other side, cheap greens will have the pump diodes just butted up against the crystal sets, Better quality greens will have focusing optics to focus the 808nm into the ND:YVO4 properly. Better quality greens will also have binned proper spec pumps that are right on 808nm. Cheap greens generally use whatever the manufacture sends them from a batch, which I think can be up to +/- 3nm which will affect performance. Usually good DPSS lasers of any type will also have temperature stabilization of some type with between one and three TEC's.. which will need drivers as well in addition to the diode driver.. So while green DPSS can be done cheap.. to do it well, and at high powers, is usually far more involved.

2: Price is generally an indicator of performance. a 200mW module for around $100 from a reputable seller will typically be around or over spec.. A 200mW module for say.. $30.. is guaranteed to be way under spec though.

3: No clue actually.. The quantum mechanics of the process are kind of beyond me, but I would assume, the longer the crystal, the more gain you'd get per pass.

4: All optics influence the beam. The raw output of a DPSS uncollimated is horrible. But I think the answer you want is yes.. Focusing a collimated laser is a matter of lens position rather than presence of lenses. A focusable laser will have the same lenses. The only difference is the focusable laser will have some mechanism for easily adjusting the position of the collimation lens where the non focusable laser will have it adjusted for a focus to infinity then fixed in some fashion where it won't easily move.

5: Most laser diodes made now days, regardless of wavelength, when run at their manufacturer spec'd power anyway, are usually rated for 10000 hours.

6: Vast majority of the heat comes from the diode. I'm sure there is some conversion of photons to heat in the crystal set as well though.

7: Mode hopping is in no way harmful and there are a multitude of reasons why it happens. Changing temperature is the primary reason in cheap lasers. Getting rid of it usually requires active temperature stabilization.

8: They are usually fairly sensitive to shock compared to diode lasers due to the complexity and sheer number of points misalignments can happen.

9: The 445nm diodes that are common in the hobby are multimode diodes. Compared to single mode diodes found in optical drives, the beam specs are going to be a lot worse. It comes down to the fact that a larger emitter area can't be collimated as well as a point source, which single mode diodes are as close to us getting as there ever will be. It's pretty much the reason why you can't get a small collimated beam out of a flashlight..

10: LM358 based drivers are still linear drivers. Your voltage input will need to stay roughly 2V higher than the vF of whatever diode you try to run with them.

11: It really depends on what your application is, and how well you can tolerate problems down the road. Just using it as a pointer, you can probably stand failures and quality issues. If you actually need it for a real on demand mission critical reason, the added cost of a guaranteed reliable product is always better.. You get what you pay for after all.

Your car is a good analogy. If you know your only going to be driving around within a few miles of home, you might not really think about using cheap parts to fix it if something broke... But if you knew you were going to be driving cross country.. repeatedly... You'd probably make sure your repair parts were of as high quality as you could find correct? And those cost a lot more than the cheap ones, but the cost is worth it because of the added reliability.

holy moly donut shop, qumefox i think you spilled some beans there, i'll pick them uP !
My beans all mine.

thanks for that.

is it your delorean in the avatar ?

so i can basically say most portable greens up to 300$ for 100mw will be the "cheap type", without the focusing lense after the diode and a separate HR mirror after the focusing lens and a separate ND:YVO4 before the KTP ?

oh right, forgot to check and mention the converting crystal ND:YAG's price because it's bonded in my module so i treated it as 1 unit heh.

are there any handheld portables on battery made by the professional method with focusing lense HR mirror ND:YVO4 separate from KTP and then the usual rest ?

though with my budget i think im gona stick to the cheapo diode directly butted to the ND:YVO4 .

LM358 linear hmm, soon i'l post pics in repair section, of my viper internals, maybe there are extra IC's that some how work with 2.4v to drive it, as i red somewhere here that reds need to operate 2-2.5v, greens 3-3.5v, violet 4.2-4.5v.

qumefox do you have in your collection a laser made the right way, separate focusing lens->HR mirror->ND:YVO4->KTP ?

Yes, that's my DeLorean.

Well by 'cheap' I mean built as simply as possible. And generally, any DPSS laser any of us will ever deal with won't have a seperate HR. It's typically done with coatings on the back face of the ND:YVO4, even when using seperate crystals. Though you don't have to spend $300 to get 'decent' green modules unless your wanting >200mW reliably. And yes I know o-like has been selling a '400mW' laser for like $220 but if you've kept up with that, you'd know they're having extreme QC problems with them now and generally they've been nowhere near spec lately.

Also generally most DPSS lasers we'd ever get our hands on well have bonded crystals as well. That in itself isn't a bad thing and simplifies a lot of alignment problems. It's only when your starting to deal with really high powers do you want to have them separate so you can control the temperatures of each individually to get the absolute maximum out of them, efficiency wise. You have to get up in the watt range or higher I believe before you start seeing DPSS with totally external cavity mirrors for both the OC and HR. And these will be side pumped as well.. not end pumped like the green's we use in portables.

Also.. DPSS pumps are typically 808nm.. They're Vf is actually a little lower than reds. not higher.

I don't have budget to have a full out everything separate and optimized high power DPSS. The closest I have is my 30mW 473nm. Which has two lenses and an anamorphic prism pair to focus the pump correctly into the crystal set.. which is still bonded by the way. It's also a dual TEC arrangement, with one on both the pump, and the crystal set.

finaly i sneaked out a few minutes out of my life to respond !

ooohh i see about the efficiency wise at higher powers, thanks for another enlightenment.

that's exactly as i interpreted you and meant when using the term "cheap", built as simply as possible. (we're on same page)

yep, i noticed the lower you go with power the closer it is to spec from the "affordable" companies, that's why i'l dock myself to not over 200mw modules.

that's a nice module brain qumefox, did you ever butted the pump into the crystal without anamorphic prism pair to see the output difference ?

did any 1 ever offered to buy your wheels ?

3: what shape of KTP crystal is better, short cavity 3x3x2 or prolonged cavity 3x3x5 ? (when the 3x3 is the entrance perpendicular to the beam)

Click to expand...

Depends what a cavity you are constructing. A chip type has a short crystals and power may reach 100 mW of green. A longer ones are used in a separate-components cavity, like a mirror+NdYVO4+KTP+mirror, and it is easy to handle a bigger parts :shhh:

6: is most of the heat produced coming from the tiny itsy bitsy diode or KTP as well ?

Click to expand...

Mainly a laser diode. KTP does not absorb much. In same circumstances nonlinear crystals are kept at elevated temperatures.
The green laser has a Nd:YVO crystal too, what absorbs a lot of a laser diode radiation, and a big part of it is taken away (dissipated by a heatsink) otherwise the green power goes down.

7: when continuing to run a laser in hoped mode (split beam) does the diode or KTP get damaged ?

Click to expand...

Probably non of them are yet damaged just reduced the laser diode current. The damaged beam would have a weird profile, not a double. Scientists generates fancy-mancy beams without destroying lasers. Google for "higher order gaussian modes"

9: why 445nm starts with such a fat beam diameter of 5mm, is that some physical property ? (that's the info i stumbled upon around here, but in 2-3 words)

Click to expand...

Depends on a collimating lens. It is a laser diode (huge divergence) not a DPSS laser.

scriewy said:

finaly i sneaked out a few minutes out of my life to respond !

ooohh i see about the efficiency wise at higher powers, thanks for another enlightenment.

that's exactly as i interpreted you and meant when using the term "cheap", built as simply as possible. (we're on same page)

yep, i noticed the lower you go with power the closer it is to spec from the "affordable" companies, that's why i'l dock myself to not over 200mw modules.

that's a nice module brain qumefox, did you ever butted the pump into the crystal without anamorphic prism pair to see the output difference ?

did any 1 ever offered to buy your wheels ?

Click to expand...

The 473nm is a labby, and it works fine as it is. I don't see the need to destroy it by tinkering. Already did that with a 589nm pen. But luckily I can probably fix that whenever I get around to ordering a new pump.

To answer your question though. I already know what would happen with removing the pump focusing optics.. It wouldn't lase. 473nm, and 589 etc, aren't nearly as efficient as green. If it was possible to make them work without the extra optics like is possible with green, then you'd see the prices for those wavelengths become noticeably lower than they are currently.

Also, what wheels am I selling?