200-300 mW green laser advice

Hi all, I am new to this forum. I have been following the forum for a long time and have learned a lot of things. I am looking for a handheld 532nm laser (>=200 mw). I will be using this laser for underwater imaging purposes, and will mount a line generating lens on it. However, looking at several posts and several companies discussed here, I am confused a lot and your assistance is very much appreciated.

I will be using this laser underwater (at depths of maximum 50 – 60 cm) in temperatures of between 3 and 15°C. It must also have longer duty cycle (say, more than 10 minutes). It seems that one of the biggest problems of the DPSS lasers is that they are very temperature sensitive and difficult to lase in cold weather conditions. Based on the posts I read here regarding the reliability of the Laserglow, I have contacted them, and they suggested me Aries laser over Hercules since Aries is passively cooled and advised to keep the laser inside a coat before using it, and wrap e.g. sock around it during its operation in very cold conditions. However, I am afraid that it will not reach its maximum power (stabilized), and even if it reaches, when I put the laser inside a waterproof housing there might be overheating problems over long term. Therefore, a laser comes with a waterproof host and sufficient room for another lens attachment would be a great fit!

However, reading the comments here and looking at the companies, finding this laser looks very difficult. I have also looked, sci Fi lasers, laserbtb and Jet lasers (waterproof models), yet it seems that they do not have long duty cycles.

Please note that due to the temperature sensitivity of the DPSS laser, I have also considered 520nm green laser as an alternative. However, due to the beam characteristics (thicker and oval), I decided not to go with it because I do not have proper skills to deal with beam shaping and lens attachments, as well as I want to keep the whole system as small as possible (hosts are already very large).

I wanted to try my chance, hoping that somebody might help me or guide me in a correct direction. Thanks a lot!

Hey tet,

If I were you I wouldn't get any LaserGlow laser due to how expensive they are and since you will be using it underwater you are taking a HUGE risk and could possibly lose quite a lot of money!

I know you said you would rather get 532nm but you are faced with a challenge. DPSS builds up heat and having 200mW of 532nm light requires a pretty strong 808nm diode so having one run for as long as you would like in a portable/handheld can be challenging. What is even more challenging is finding a waterproof 100% duty cycle 532nm 200mW laser, if you can skip on getting 532nm and get 520 it will be much easier to obtain 200mW from it and can possibly run you a little cheaper.

Do you have the links to the different lasers(except the laserbtb one)?

-Alex

Not sure how set you are on 532nm, but you can get a 520nm that is depth-rated (for scuba diving) for a fairly reasonable price from lasertb here:

Diving laser 50 meters

In other news, I'm actually working on buiding a couple of waterproof lasers to take diving with me. I've got everything done but putting diodes in. If you are interested, shoot me a PM and I can show you what I've got. Maybe you'd be interested.

Is there any reason it needs to be 532nm?

I don't think there is a 532nm handheld on
the market that can do this. Temperature
control and waterproof and handheld and
>=200mW is a lot to ask. Keeping it in a
coat and sock is completely ineffective
once it touches that cold water. It would
be much less of a headache to use 515-520nm
direct diode. The color is very close and
it doesn't have any of the temperature
problems of the 532nm.

Thanks a lot for your comments and suggestions!

Alex, I have looked Jet lasers Pl-e-pro and Lazerer 100 mW (low power but waterproof). The following two lasers is claimed to work in low temperatures, do you have any experience with these companies?
NQ-513 300mW
NQ-508 300 mW

There is also 635nm version, which might be of your interest.

I strongly agree that it is even more difficult to find a waterproof laser, however, please note that I can also put the system inside a waterproof housing so that it might not be directly exposed the cold weather. Considering that I will use a 532nm laser at its operating temperature (Spring is coming ) what would you expect in terms of operation time? Also, this may be a dumb question, but what is the difference between the lab laser and handheld laser apart from portability. In any case, I am planning to extend a cable to the battery compartment so that I can change the batteries without opening the laser, and therefore, without changing the alignment of the laser sheet. I contacted CNI laser, and they offered me MGL-S-532-A 300 mW model with a line generating lens, but the price was much beyond my budget.

Regarding the 520nm, there were, in fact, two reasons that I have not considered too much. However, I would be glad to hear about your opinion and suggestions for 520nm laser with power of over 200 mW and a waterproof host (I can also design a housing for them):

1) As I mentioned, I will be using the laser for underwater imaging purposes underwater. For my application, I am using a camera with Sony IMX117 image sensor. I have contacted the company concerning the quantum efficiency or normalized spectral response of the sensors, however, they are not willing the share this information . I have then looked at different CMOS sensors and cameras in the market, and found out that most of them have a better spectral sensitivity at around 532nm compared to 520nm.

2) Another reason is that that beam of the 520nm is oval, and I wanted to use a line generating lens directly attached to the head of the laser. As I mentioned before, I am not too much skilled to deal with different lenses, and would prefer keeping system as small as possible.

Thanks again for the suggestions.

If you find a suitable 520nm laser and some way of keeping it waterproofed, you could use a line lens with it, the line won't be all that much thicker. Maybe you need an extremely fine line, in that case, 532nm is better and I just wasted some time responding, but something to consider. I am betting the difference in sensitivity for a camera at 520nm compared to 532nm is about 20 percent less, if designed to mimick the sensitivity of our eyes to those colors.

tethys said:

I strongly agree that it is even more difficult to find a waterproof laser, however, please note that I can also put the system inside a waterproof housing so that it might not be directly exposed the cold weather. Considering that I will use a 532nm laser at its operating temperature (Spring is coming ) what would you expect in terms of operation time? Also, this may be a dumb question, but what is the difference between the lab laser and handheld laser apart from portability. In any case, I am planning to extend a cable to the battery compartment so that I can change the batteries without opening the laser, and therefore, without changing the alignment of the laser sheet. I contacted CNI laser, and they offered me MGL-S-532-A 300 mW model with a line generating lens, but the price was much beyond my budget.

Click to expand...

This isn't a bad idea. If you could design
such an enclosure that had a 532nm AR
coated window, that would be one way to
go. I would also recommend attaching a
temperature sensor.

A decent labby will have full temperature
control and hence a more stable output.
The temperature issues will not be to the
same degree as they are with a handheld.
The only issue will be the power supply and
any umbilicals needed for power delivery.

tethys said:

Regarding the 520nm, there were, in fact, two reasons that I have not considered too much. However, I would be glad to hear about your opinion and suggestions for 520nm laser with power of over 200 mW and a waterproof host (I can also design a housing for them):

1) As I mentioned, I will be using the laser for underwater imaging purposes underwater. For my application, I am using a camera with Sony IMX117 image sensor. I have contacted the company concerning the quantum efficiency or normalized spectral response of the sensors, however, they are not willing the share this information . I have then looked at different CMOS sensors and cameras in the market, and found out that most of them have a better spectral sensitivity at around 532nm compared to 520nm.

2) Another reason is that that beam of the 520nm is oval, and I wanted to use a line generating lens directly attached to the head of the laser. As I mentioned before, I am not too much skilled to deal with different lenses, and would prefer keeping system as small as possible.

Thanks again for the suggestions.

Click to expand...

Unless you need a very fine line at tens of
feet, as Alaskin said above, it won't make
very much difference. Direct green is a
little cheaper per mW, so any sensitivity
issues with the camera can be offset.