O-like OLNG350 350mw 532nm

[plexus]

Purchase

I purchased this laser 9 Feb 2011 but because of the Chinese New Year I did not get a shipping notification until 15 Feb. It was shipped out on 16 Feb by the optional DHL express service. It arrived in my hand on 17 Feb (!!!) Very fast and worth the extra $15 (to me).

Appearance & Features

The laser is very well machined with a nice smooth semi-gloss surface that feels very top quality.

Here it is compared with some other lasers (from bottom to top: Wicked Lasers Arctic, O-like OLNG350, Wicked Lasers E3, Aurora SH302 host, O-like "Cute" 250mw 650nm):

The tail cap has a key switch on it. this is actually very useful and provides for a good safety feature. the annoyance of having to use the key to arm the laser, or not is out-weighed by the safety aspect of it. The positive tail cap is well made and serviceable"

The power switch is very nice and feels nice. its a soft press toggle on/off. when off it glows blue and when on it glows red. there is no time delay.

The switch is illuminated blue when the key switch is on (armed mode) and red when the laser is on. You can see the switch is illuminated with 3 board mounted LEDs.

The front aperture has a manual aperture lever. pushing the lever down opens the aperture leaf and pushing it towards the aperture, closes the aperture. this is another good safety feature. i always make sure to close the aperture before i turn the laser on and then use the aperture lever to open it. this way i don't inadvertently turn the laser on while its pointed at something i don't want it to be (like my eyes). also the main switch is very soft touch so its easy to accidentally turn the laser on by accident. so the aperture leaf is a welcome safety feature.

one gripe i have is that when the laser is keyed-on the blue lights are on. this means there is power draw and you have to make sure to key-off the laser before putting it to bed for the night, or else your battery will drain. but like i said having the key switch is better than not and it forces me to only key-on the laser when i am going to use it (safety).

The heat sink is quite massive and I think it might be made of brass, considering the weight of the laser and the balance of the weight toward the head. The main focusing lens is on a thin but wide disk that threads into the heat sink (I have removed the IR fliter, and the residual white silicone can be seen):

Internal Design

This is module with the focusing lens removed. you can see a secondary lens glued to the output of the module. the lenses appear to be glass:

The battery compartment is a plastic sleeve inside the host. This makes the battery fit nice and snug but with enough clearance to slide out without effort. The inner battery spring has no other support so this could be a problem in the future with perhaps the spring coming loose. I hope there is a good blob on solder holding it to the driver!

I think they are using a constant current driver because as the battery depletes the output remains quite constant (unlike the "cute" 250mw 650nm which I think is a linear driver as the output of the laser drops as the battery drains).

IR Output

I measured the stock IR filter vs another IR filter. the other IR filter i purchased from ebay and seem to be a common one used with laser diodes. however i don't know which does the best job of only filtering IR.

The stock filter is a thin piece of glass that has no tint. When the laser was outputting an average of 380mw, the stock IR filter reduced this down by 20mW, or 5.2% of total. The other IR filter (Schott BK38) dropped this down by 60mW, or 15.8% of total - 3x more IR attenuation. In the meantime I ordered a lab grade visible light pass-through filter from an ebay seller so I can get a better handle on how much IR my lasers are producing. But BK38 is pretty standard so I think the stock IR filter is only reducing the IR marginally and I would say is still at an unsafe level. BK38 attenuates the 800-1100nm region down to about 2-4%.

As a note, there is a lot of interest in DPSS lasers with IR filters in terms of whether they have them or not and how much IR is produced. We all want to trust the rating manufactures give us and we've all seen some lasers that produce upwards of 30% of their output as IR. Some people have used cheap goggle to filter out IR or even IR filters made for laser pointers. Unless a filter is used that has a measured spectral response, you will never really know for sure. If you are concerned or interested in measuring IR vs Visible you might want to consider buying a measured and documented filter for such purposes. There are often lab grade filters on ebay. When I get mine I will update this review and we will then be able to say for sure how much IR this produces.

For now, lets say the laser produces somewhere between 5-15% of IR in its total output, which pretty typical.

UPDATE: I just realized I have two IR filters for photography. Ones happens to cut off under 950nm and the other under 720nm. so perfect for measuring the IR in these DPSS lasers! also these are pretty high quality filters and I believe they are at least 85% transmissive if not more.

With the 720nm pass through I read 40mw and with the 950nm i read 26mw. so that means about 13mw of 808nm and 26mw of 1062nm. so this tells us that the stock IR filters is still letting through about 20mw of IR and that the Schott BK38 is cutting an additional 20mw of the 532nm output. for this laser, when outputting 420mw of total power to only have 40mw of IR is pretty good!

Here is a horizontal beam comparison between some similar lasers. The top is the OLNG350, middle is an Ultra Lasers 100mW pen and bottom is a 280mW labby. Notice how the OLNG350 has a wider beam waist and hence lower power density. This is, I think, because they are using larger crystals to keep the interface temperatures down. You still get more light out of it but in a wider area. The OLNG350 has a waist about twice that of the 100mW, which can use smaller crystals, and the labby which is TEC cooled. (This was a very difficult picture to capture.)

This is a picture of the laser output without the front most focusing lens.

This is the beam profile, without the front focusing lens, about 2m from the aperture. The beam profile is more rectangular than round. It is pretty stable but there is some mode hop now and again. The instability is more pronounced when the laser is cool:

Measurements

The graphs in this review are with the stock IR filter. I did them before I thought of trying the other IR filter. so adjust your expectations accordingly.

This graph shows a 5 minute run from room temperature on a fresh AW 18650 2600mAh:

Then I switched the laser off for about 10 seconds before I started the next run from 5-10 min:

And here is 10-15 mins:

From the above, it appears the laser needs to be on for 6 minutes or so in order to stabilize. This is very interesting... I wonder if its a combination of larger Vanadate and KYT in combination with a large heatsink.

So I would say that this laser can be considered a continuous duty cycle laser for all intents and purposes. It was pretty stable after 15 mins of what was basically continuous output. However, I have noticed that the module likes to be warmed up first. Here are some more graphs experimenting with duty cycles after the laser was warmed up for those 15 minutes. As you can see, turning it off for 30-60 seconds and back on produced some impressive peak power outpus:

Here is a power plot from the laser at room temperature, not having been run for a day, with a freshly charged battery, for 15 minutes. Note how it takes about 7.5 minutes to stabilize. After that for the other 7.5 minutes it runs within an average of about 390mw +/- 30mw. After the 15 min the laser was pretty warm. I was lazy and didn't record a temperature graph while it was running (with my logging digital thermocouple) but one day i will do this. Also note this was done with NO IR filter. So revise the numbers down about 10% for just the 532nm light.

Beamshots

Here are some beamshots. This photo includes an 880mW 445nm WL Arctic, 560mW 405nm and O-like "Cute" 250mw 650nm, for comparison:

Conclusion

I am very impressed with this laser. The high quality construction, ample heatsink and great output characteristics are impressive and well worth the $295US price tag. The IR content is pretty typical of this kind of DPSS laser. The stock IR filter should be replaced with a better BK38 or equivalent filter to effectively eliminate IR in the output, otherwise there will be unsafe levels of IR in the beam. I do not consider 532nm lasers the best for burning so I am not going to go into detail on burning capabilities. 532nm is the best for visibility and you can see this in the beamshot. The visible output is quite impressive. Over-all a very recommended laser.

 

[snoutke]

:thanks:for a comprehensive review!

Now I have serious inner conflict whether to order this laser or to order the O-like 400mW for 208$ when it is restocked. It is quite a price difference comparing to this 295$ laser.

Could you help me make a decision?

 

[madog]

Thanks for the detailed review.

 

[plexus]

@madog you're welcome

@snoutke yes, this was the same dilemma i had. to wait for the OL-532-350 or get something like the OLNG350. here are my thoughts on the matter but remember this is just my own thinking about it and i have never seen or used the OL-532-350...

There is a lot of attention by people to having lasers that burn. In my experience, 532nm is not as ideal a burning wavelength as 405 or 445. the latter seem to be absorbed better by materials, can focus to a smaller beam waist and are more easily high power for a given $. also DPSS lasers, especially those in portable hosts, can be unstable which affects the power in a focused spot. 532nm is best for visibility.

Knowing that DPSS lasers require a certain band of temperature to operate in, and that too hot or cold and you don't get peak power, I felt the OL-532-350 would have such a short duty cycle that it would not be as much "fun" as the OLNG350 with its larger heat sink. of course, not owning the OL-532-350 I could not be sure. But it seemed to me that the OL_532-350 was made more as an on-paper high-horsepower laser aimed more for people that want to burn things (hence the focusing feature). the fact that it didn't come with an IR filter as well seemed to imply this. the problem with DPSS lasers without IR filters is you don't really know how much of the total output is going to be IR (unless someone does a good review and measures this using high quality IR filters [and not, say, googles to do the filtering]).

So did I want to spend $208US on a laser that I am not sure how much its going to output on average or $87 more to get one that is going to output a rated 350mw average (and maybe more if its over-spec). And also, have the larger heat sink to keep the module in a peak operating range. There seemed to be more likelihood that the OLNG would operate for a longer duty cycle at higher and more consistent output than the OL just based on the descriptions and what little review info there was about these two.

So I opted for the OL and I believe I made the right choice. it has exceeded my expectations in that, once it has warmed up, will do peak >500mw and average >350mw (but more like 450mw) over longer duty cycles.

When you look at a laser like the "cute" 250mw 650nm they sell, that laser sure does >220mw but only for a few moments on a freshly charged battery. then it drops to an average of 170mw. this is typical of the cheaper laser pointers where the spec is the peak output and not the average output. this was another factor that added to my decision.

My advice is not to be swayed by the price and advertised specs as much as, if they are available, reviews of the lasers. but make sure that the reviewer is providing well documented and thought out methodologies. for example, using googles to filter out the visible like and read the IR on the other side is meaningless because the plastic of the google lens is going to absorb IR too and so the IR reading on the other side is not going to be accurate. When it comes to DPSS lasers, heat dissipation and consistent crystal temperature is very important. failing TEC cooling, a large heat sink will help to keep the laser in the sweet spot. the OL laser has too small a heat sink for its rating, IMHO - you might get 350mw peak 532nm out of it, but the power will likely drop drastically as it heats up faster because of the small heat sink.

Hope that helps.

PS. It is tempting to get an OL-532-350 to test but I am not sure I want to spend the $ just to do that. pity.

 

[david1235102]

@madog you're welcome

@snoutke yes, this was the same dilemma i had. to wait for the OL-532-350 or get something like the OLNG350. here are my thoughts on the matter but remember this is just my own thinking about it and i have never seen or used the OL-532-350...

There is a lot of attention by people to having lasers that burn. In my experience, 532nm is not as ideal a burning wavelength as 405 or 445. the latter seem to be absorbed better by materials, can focus to a smaller beam waist and are more easily high power for a given $. also DPSS lasers, especially those in portable hosts, can be unstable which affects the power in a focused spot. 532nm is best for visibility.

Knowing that DPSS lasers require a certain band of temperature to operate in, and that too hot or cold and you don't get peak power, I felt the OL-532-350 would have such a short duty cycle that it would not be as much "fun" as the OLNG350 with its larger heat sink. of course, not owning the OL-532-350 I could not be sure. But it seemed to me that the OL_532-350 was made more as an on-paper high-horsepower laser aimed more for people that want to burn things (hence the focusing feature). the fact that it didn't come with an IR filter as well seemed to imply this. the problem with DPSS lasers without IR filters is you don't really know how much of the total output is going to be IR (unless someone does a good review and measures this using high quality IR filters [and not, say, googles to do the filtering]).

So did I want to spend $208US on a laser that I am not sure how much its going to output on average or $87 more to get one that is going to output a rated 350mw average (and maybe more if its over-spec). And also, have the larger heat sink to keep the module in a peak operating range. There seemed to be more likelihood that the OLNG would operate for a longer duty cycle at higher and more consistent output than the OL just based on the descriptions and what little review info there was about these two.

So I opted for the OL and I believe I made the right choice. it has exceeded my expectations in that, once it has warmed up, will do peak >500mw and average >350mw (but more like 450mw) over longer duty cycles.

When you look at a laser like the "cute" 250mw 650nm they sell, that laser sure does >220mw but only for a few moments on a freshly charged battery. then it drops to an average of 170mw. this is typical of the cheaper laser pointers where the spec is the peak output and not the average output. this was another factor that added to my decision.

My advice is not to be swayed by the price and advertised specs as much as, if they are available, reviews of the lasers. but make sure that the reviewer is providing well documented and thought out methodologies. for example, using googles to filter out the visible like and read the IR on the other side is meaningless because the plastic of the google lens is going to absorb IR too and so the IR reading on the other side is not going to be accurate. When it comes to DPSS lasers, heat dissipation and consistent crystal temperature is very important. failing TEC cooling, a large heat sink will help to keep the laser in the sweet spot. the OL laser has too small a heat sink for its rating, IMHO - you might get 350mw peak 532nm out of it, but the power will likely drop drastically as it heats up faster because of the small heat sink.

Hope that helps.

PS. It is tempting to get an OL-532-350 to test but I am not sure I want to spend the $ just to do that. pity.

You could ask Susie if they can send you one as a free sample or for a discount to do an extensive review on it. You could also buy one to do the review then resell it here saying that it is brand new just used to test output and to make the review. You probably wouldn't be out much if you did that unless the laser was underspec.

 

[AAlasers]

First of all, very nice review! I believe that you have convinced me to be slightly less cheap than I normally am, in that I will purchase this laser rather than the lower quality "waterproof" "400 mw" green laser. I would be wary of bringing any $200 laser underwater anyways. I have one question, how is the divergence? Is it noticeably bad, passable etc.

Thanks,

AAlasers

 

[plexus]

@AALasers Keep in mind, I have never seen an OL-532-350 in person, so I cant speak for it directly. The divergence of the OLNG350 seems ok. I wanted to measure it but its been snowing and it takes some time to set it up up and measure. But the beam is wider right out of the aperture than you might typically see. I think this might be beacuse of larger crystals being used which would be an overall plus because it means lower coupling interface heat build up and longer crystal life and perhaps better consisiency. maybe. i have no ways of measuring these thing.

Despite the guessing, the actual laser is pretty great in use. i dont think the little one would be any better and i am getting good consistent power output.

 

[AAlasers]

@AALasers Keep in mind, I have never seen an OL-532-350 in person, so I cant speak for it directly. The divergence of the OLNG350 seems ok. I wanted to measure it but its been snowing and it takes some time to set it up up and measure. But the beam is wider right out of the aperture than you might typically see. I think this might be beacuse of larger crystals being used which would be an overall plus because it means lower coupling interface heat build up and longer crystal life and perhaps better consisiency. maybe. i have no ways of measuring these thing.

Despite the guessing, the actual laser is pretty great in use. i dont think the little one would be any better and i am getting good consistent power output.

Yes. Your review of this laser has simply made me lean closer to getting the seemingly higher quality laser, as it provides actual evidence backing up my suspicions on this laser having higher quality parts than the other.

Thanks,

AAlasers

 

[plexus]

Update in the IR section. good news for this laser!

 

[Moebius]

Very informative review. I especially like the multi-color illuminated switch. This is a really good looking host.
May I ask how you can operate it for these extended periods when it's stated duty cycle is only 100 seconds?

 

[plexus]

The proof is in the pudding. the published specs for these kinds of things are often suspect. the only way to know is to measure it yourself. you can see by the graphs that it can take much longer duty cycles. there are no major drop outs over the extended periods of time so this indicates no major optical trauma. however it is true that these longer duty cycles may do damage. but so far there is no evidence of this. once its warmed up, i think after being on 2 minutes the power would drop from the ~500mw peaks to about 300mw. i should try/chart this sometime. so it may be that o-like is referring to the 100 second duty cycle as not so much being to reduce laser damage but to ensure you are getting average documented power of that period of time.(?)

 

[snoutke]

plexus, you surely bring up the right considerations.

You make me more and more tend for the OLNG350 350mw 532nm.

Since I'm also interested in burning, I will appreciate if you tell a little bit about this laser's burning ability because this laser doesn't have a focusing mechanism while the OL-532-350 has, a fact that makes the OL-532-350 more 'burning friendly'.

And one more thing: Does this laser have a momentary switch or is it an on/off switch?

 

[plexus]

snoutke, 532nm doesn't work well for burning. I am not sure why. I think that most things don't absorb 532nm as well as other wavelengths. for burning a >300mw 405nm or ~1W 445nm is your better bet. You will get way more burning power out of a $200 1W 445nm than you will out of a 400mw 532nm so if burning is your quest, best to look for a direct output 445 or 405. but if you want green and want to burn, the OLNG350 will do both but I don't have much to say about its burning capabilities because it not my go-to laser for that (my 550mw 405 is the best one i have for burning).

The OLNG350 has a toggle on/off switch.

 

[snoutke]

I already have the DL 1W Spartan which is a heck of a burner.

Now I want to get a good green.

I'll take all your insights into consideration and make my decision soon.

Thanks.

 

[SteveIsNowHere]

@ plexus
This is one of the greatest and well-detailed reviews on the forum! Hats off!

The battery compartment is a plastic sleeve inside the host. This makes the battery fit nice and snug but with enough clearance to slide out without effort. The inner battery spring has no other support so this could be a problem in the future with perhaps the spring coming loose. I hope there is a good blob on solder holding it to the driver!

I got from O-like the IR filtered 450mW 532nm Green laser torch - Model: OLNGL400
http://www.o-like.com/index.php?main_page=product_info&cPath=2&products_id=42
The housing basically the same. (I have not gotten any sticker on it tough.) I have not gotten even the safety eyeglasses that -according to the item's description- was supposed to come with the laser. Wrote them, no answer.

Here is my experience with this inner battery spring:
This spring is soldered with a tiny drop of tin to the circuit board. After the 2nd use the spring was bent then broken off by the 18650 battery from the circuit board (driver) and since then my torch is useless. The construction is horrible. There is no support/protection around the spring at all. The 50mW 6 in 1 and the "cute" lasers got the support for their spring...these torches-->not.
I wrote an e-mail several days ago to Susie in order to ask for help however no one got back to me...

Here are some before and after pictures:

This picture was taken by me right after I got the package:

This picture was made after the trouble happened:

This is the culprit:

Unfortunately, I do not know how to fix it. Right now I stuck with a useless laser...

Before ordering think twice because this can happen to anyone who orders this kind of construction. It's only question of time.



PS: The last photograph that you made about the beams were made using fog or it was a long exposure picture? The reason I ask because my "cute" 300mW red laser's beam can not be seen at all in a dimly lit room and just barely can be seen in a dark room.

 

[plexus]

That is highly unfortunate that your laser broke like that. of course you have to get in there to fix it and i am not sure how. if it were me, i would be trying to get the module out from the front. i think the the whole thing is a module and it probably just screws out through the front, assuming you can get the power switch off etc. then solder the clip back on. but yes, thats a not a good design and to only rely on the solder to hold the spring on is, as you say, a poor design.

The beamshots were taken with some smoke in the air. not enough to really see with the lights on but enough to allow the beams to show up. its also a very long exposure with a closed lens (lens f3.5, stopped down to f13 with about a 40 second exposure, or there-abouts).