Help a scientist - laser pointer request

[rioimmagina]

Good day gentlemen,
I'm a flashaholic since 2009, happy owner of several torches, but never paid much attention to lasers..... so far.
In my privat life, i'm a chemist and i work in the global research facility of a construction material company. Recently I arranged a set-up for a qualitative determination of water emulsions, through the so-called tyndall effect.
As a laser source i've used a cheap chinese 1mw red pointer. The apparatus is kinda working but i would like now to step up with a reliable, wavelenght certified laser source.
I've lurked a bit around the laser threads, checked some producers (like wicked laser) and also found on this very pages an interesting guide... the problem is that i don't need high power and apparently the market is moving in that direction.
So I ask you, kind audience, to point me towards a laser with the following features:
1 to 5 mw
Blue color, reliable wavelenght
Compact
Regulated
True switch (not just the momentary on, or I'll need to tape it to keep it firing)
Maybe a rail or kind of attachement to link it to a support.
Well, that's it. It's going to be a lab equipment so i would like a quality product. Maybe i will buy more than one in different powers and wavelenghts.
Thanks for reading
Ciao

 

[Gun]

Blue lasers don't really come in 1-5mW power, they only come in higher outputs. So unless you want to get something very powerful, you can't get blue. Is 532nm (Green) going to be okay for you? and are you looking for a handheld laser or a plug-in "lab" laser?

Thanks,
Gun

 

[rioimmagina]

R: Help a scientist - laser pointer request

Blue lasers don't really come in 1-5mW power, they only come in higher outputs. So unless you want to get something very powerful, you can't get blue. Is 532nm (Green) going to be okay for you? and are you looking for a handheld laser or a plug-in "lab" laser?

Thanks,
Gun

Hi Gun, thanks for answering.
So far I'm using a red 620nm pointer.
Going down in wavelenght would increse the scattering intensity, so I guess a green source would be still ok. High power laser would only blinds my camera and myself.
I would prefer a handheld, battery powered device, for the sake of comfort, but I'm ready to evaluate other solutions...

 

[Gun]

Re: R: Help a scientist - laser pointer request

Although THIS pointer is expensive it's been rated as the best 5mW pointer out there, extremely reliable. Don't buy from Ebay as most of them will be a lot more powerful than 5mW and if you're not wearing safety goggles they will damage your eyes. If you're not willing to pay the $50 for the LaserGlow then I recommend referring to THIS thread from the Laser Pointer Forums, there's tons of information in there about who to buy from, and who not to buy from.

Thanks,
Gun

 

[rioimmagina]

R: Help a scientist - laser pointer request

Although THIS pointer is expensive it's been rated as the best 5mW pointer out there, extremely reliable. Don't buy from Ebay as most of them will be a lot more powerful than 5mW and if you're not wearing safety goggles they will damage your eyes. If you're not willing to pay the $50 for the LaserGlow then I recommend referring to THIS thread from the Laser Pointer Forums, there's tons of information in there about who to buy from, and who not to buy from.

Thanks,
Gun

Thank you, that seems exactly what I was looking for! They have a lot of choice, i will dig in the website.
Thanks again

 

[Gun]

Re: R: Help a scientist - laser pointer request

Thank you, that seems exactly what I was looking for! They have a lot of choice, i will dig in the website.
Thanks again

No worries, if you have anymore questions don't hesitate to ask :)

 

[bshanahan14rulz]

Re: R: Help a scientist - laser pointer request

It sounds like you require a very stable wavelength, and DPSS process is very good at creating a stable 1064nm. If visible radiation is needed, easily frequency doubled down to 532nm. Nd:YAG also has transitions at ~946nm, which can be frequency doubled down to ~473nm.

532nm is your typical green laser pointer. If all you need is wavelength stability and not output stability, go for a cheapo green pointer, or a more expensive green laser with a clicky button (like a flashlight has). You may also need to find and purchase an IR filter, or specifically request a laser with integrated IR filter.

Lab style lasers are available too, and feature more thermal mass. Often times, it is just the portable modules that go in pens, but in a non-rolling heatsink. A stable, good quality lab laser, however, can set you back quite a pretty penny.

One thing to keep in mind about diode lasers, is that their wavelength varies as a function of their temperature, as much as a few whole nm!

 

[rioimmagina]

R: Help a scientist - laser pointer request

It sounds like you require a very stable wavelength, and DPSS process is very good at creating a stable 1064nm. If visible radiation is needed, easily frequency doubled down to 532nm. Nd:YAG also has transitions at ~946nm, which can be frequency doubled down to ~473nm.

532nm is your typical green laser pointer. If all you need is wavelength stability and not output stability, go for a cheapo green pointer, or a more expensive green laser with a clicky button (like a flashlight has). You may also need to find and purchase an IR filter, or specifically request a laser with integrated IR filter.

Lab style lasers are available too, and feature more thermal mass. Often times, it is just the portable modules that go in pens, but in a non-rolling heatsink. A stable, good quality lab laser, however, can set you back quite a pretty penny.

One thing to keep in mind about diode lasers, is that their wavelength varies as a function of their temperature, as much as a few whole nm!

I see your point, and at the beginning i was thinking to a lab style device. Nevertheless, such a price level is almost impossible to justify for a qualitative measurement. Moreover, those lasers are bulky, come with high power and are definetely too much for the task, especially considering that my "detector" is an olympus bridge.
Imagine, i'm the only chemist in a construction material lab, among engineers and concrete technologists and being a commercial company, i need to "sell" to the management every big equipment I buy...
Hence, for the time being, i would stick to easier devices, provided a good quality.
If i have to choose between output stability and wavelenght stability, i would go for the latter, being the scattering intensity scaling with the fourth power of the wavelenght, thus affecting my measure much more than output fluctuation.
Why do you think I may need an IR filter?
Thank you for the support!

 

[bshanahan14rulz]

Re: R: Help a scientist - laser pointer request

IR filter would be to filter out the IR that is used to create the final output wavelength. IR may interfere with your sensors, scattering at a different intensity, and then being detected by the sensors that might not be able to differentiate between wavelengths. Also, cameras can usually pick up IR, so your particular sensor may also see the IR emitted from the laser.

I would choose a 532nm green laser, and make sure that it is IR filtered. You can also buy IR filters, although only place I could find with a quick search was o-like, and they are over in China.

You can find <5mW green pens from the more reputable companies, often they will be IR filtered. I only have a WL Core as my only filtered 532nm, and I received it as a gift from WL for proofreading their site (Hey, even if I don't agree with a company's practices, free laser!)

 

[AnAppleSnail]

Re: R: Help a scientist - laser pointer request

Green lasers are actually infrared lasers with special parts to double the frequency of light emitted. This part is not 100% good, so infrared light passes through with the beam. "Good" green lasers have an excellent IR filter. Bad ones do not, and this IR can cause interesting effects. At power levels over 5 mW total, the IR leakage can be damaging to eyes.

 

[rioimmagina]

R: Help a scientist - laser pointer request

IR filter would be to filter out the IR that is used to create the final output wavelength. IR may interfere with your sensors, scattering at a different intensity, and then being detected by the sensors that might not be able to differentiate between wavelengths. Also, cameras can usually pick up IR, so your particular sensor may also see the IR emitted from the laser.

I would choose a 532nm green laser, and make sure that it is IR filtered. You can also buy IR filters, although only place I could find with a quick search was o-like, and they are over in China.

You can find <5mW green pens from the more reputable companies, often they will be IR filtered. I only have a WL Core as my only filtered 532nm, and I received it as a gift from WL for proofreading their site (Hey, even if I don't agree with a company's practices, free laser!)

Yes, i heard about WL... but a free laser it's still a free laser!
Back to the cooling issue and the related wavelenght shift, well, that might be a problem... i could cool down the source with a fan. I have access to liquid nitrogen, but perhaps it's too much...

Green lasers are actually infrared lasers with special parts to double the frequency of light emitted. This part is not 100% good, so infrared light passes through with the beam. "Good" green lasers have an excellent IR filter. Bad ones do not, and this IR can cause interesting effects. At power levels over 5 mW total, the IR leakage can be damaging to eyes.

Very intersting point guys, thank you, I didn't think about the IR issue. I will definetely look with something with a good filter.

 

[LaserCo]

Re: R: Help a scientist - laser pointer request

Hi Gun, thanks for answering.
So far I'm using a red 620nm pointer.
Going down in wavelenght would increse the scattering intensity, so I guess a green source would be still ok. High power laser would only blinds my camera and myself.
I would prefer a handheld, battery powered device, for the sake of comfort, but I'm ready to evaluate other solutions...

I thought you might need to know that there are no 620nm red pointers

the common red pointers go from 635 to around 670nm

 

[Eidetic]

There are many sources of low powered blue lasers. I'd recommend buying one for stability and simply attenuating the output by use of a polarizer mounted in front of it. You'll have the safe power level you want and the predictable convenience of a stable lab laser for your application. If you're still looking, I'll post links.