I currently work at a university, I pulled down the academic paper listed above, accessed on 11/13/2015. I hereby include a paragraph of it under the US Copyright Scheme Educational Use Clause, and for Laser Safety Purposes.
I Quote the hardware portion of the paper:
Laser treatments
In vitro assays
A near-infrared laser was used in all experiments. Specifically, an 810-nm GaAlAs laser diode system (driver, temperature controller, and cooling mount) with a fiber optic delivery system (400 uM fiber) (all from Newport) was used in continuous wave mode. Laser dose was checked before each experiment with a power meter (Newport). Power density (irradiance, W/cm2) was varied to achieve various energy densities (fluence, J/cm2) for treating samples. For example, a spot size of 20, 30, or 50 mm for four wells in a 96-well plate, one 35-mm dish, or one 60-mm dish, respectively, was used by varying the target distance (beam divergence, 15°) and adjusting power (irradiance, W/cm2) assessed with a power meter. All treatments were performed as described earlier, and treatment time (5 min) was kept constant in all experiments. Owing to variations in laser output at very low power levels and attenuation by cell culture plastic and medium, a 10% dose variance was included in all in vitro experiments. Cell-free solution experiments were performed in black wells, whereas cell treatments were performed with a black background (card sheet) placed below the clear-bottom culture dishes or wells.
In vivo assays
The same laser unit described above (Newport) was used for in vivo (mouse and rat) experiments. This unit has a 400-?m fiber delivery system, and the end piece was placed directly on the exposed pulpal tissue and used at 0.01 W/cm2 for 5 min in continuous mode for a total dose of 3 J/cm2. The end piece was moved continuously in a smooth, uniform motion during treatments to ensure that there was no appreciable heating. Animals were treated only once and followed for 8 weeks (mice) or 12 weeks (rats).
End Quote.
So they used 810 nM laser out of a 400 um core diameter fiber, which suggests the Newport unit is capable of emitting quite a bit of raw power. Commercial use of diode arrays with 400 uM cores is typically reserved for driving other lasers as a pump. 400 uM is typically used foo 20 watt and up diodes. This is a big one, as in tens of Watts of CW optical output, possibly as much as 40-50 Watts.
I did a little more digging and this is actually from Spectra Physics Lasers, which was Bought by Newport and Runs as a pretty much independent corporation, except for sales.
My best guess as a laser professional is that this a fiber coupled pump (FCL) or a Fiber Array Pump (FAP) laser usually used for pumping a ND:YAG laser, hence the 810 nanometer nominal wavelength. The laser changes wavelength at 0.2 nm/'C, and they die if ran too hot, hence the TEC controller to keep the laser cold.
Its coming out of a 400 um core fiber, which means its a reasonably uniform cone of light, diverging like crazy at 15 degrees full angle, as the fiber does not have a collimating lens on it. Its still a laser, it still focuses to a small diameter on the retina, and its still coherent, making it an eye hazard. In every sense of the word.
810 is downright hazardous without laser safety glasses, as it penetrates to the cornea, is strongly adsorbed by the retina, looks like a very dim red as the eye just barely detects it. 50 watts of 810 pointed at a wall looks like a dim red LED where the spot hits, if done under controlled conditions, and this is one of the hazards we train for. We use black and white CCD cameras or Find-R-Scopes (image converter tube) to deal with visualizing these wavelengths.
So while I can easily find the used FAP on Ebay, it needs a chiller and a high amperage constant current driver with no voltage spiking or current overshoot at all, as laser diodes and laser diode array modules are very sensitive beasts that run away without current limiting and soft start., A ballast resistor just isn't good enough to drive one. Even high power FAP arrays die if you sneeze. The right diode laser driver does not grow on trees and rarely shows up used. This is not a project for a beginner.
The authors of the paper had 5-15K$ worth of laser gear.
The laser power meter with a thermal head capable of accurately measuring this is 1500-2000$ new. Probably 500$ used. A couple of pairs of 175$ certfied safety glasses are needed. His campus Laser Safety Officer needs to know if he's doing this, as the specular reflection off the cell trays is an eye hazard and needs to be dealt with, by totally enclosing the experiment.
You should find a competent laser technician, electrical engineer, or physicist to help you with this. Most large research campuses have a local laser user who can advise you.
The laser you linked in the first post is the wrong wavelength at 950, and that matters in bio applications. 808-810 nm is a very common laser diode.
A key phrase here is energy density, and unless you have an accurate laser power meter, you can really mess up this experiment.
MY advice is based on 25 years of working with a wide array of lasers in industry, laser shows, and academia. I am a certified Laser Safety Officer. This laser is not in the toy class. It is a Class IV laser hazard under the international safety scheme. Which means its capable of starting a fire, and is an eye hazard even from a indirect, scattered, beam.
You should be aware that this type of laser is hazardous. It requires users to have proper, professionally made, Eye Protection.
Steve
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