Used professional laser economic efficiencies - cosmetic IPL laser as pump for NdYAG?

[Coogoolian]

So..... Intense Pulsed Light cosmetic laser cosmetic systems use diode bar stack arrays of (almost always) 808 nm "off the shelf" wavelengths (presumably a side-channel that the industry uses to offload their specialized Mil Spec, high energy physics lab gear, and industrial thin disk laser pump modules).


The light is not subjected to a typical fast and slow axis correcting optical setup.


Instead its passed directly into a prismatic "beam homogenizer" or "light guide" for delivery from the handpiece to a slightly compressed spot area (and often with conduction cooling effects by sinking the optical element to a TEC so that the tip is cold on the skin)


Why might this be useful?

Becuase, as eluded to above, Beam homogenizers are used in other applications that involve diode bar stack arrays, including applications in which they are used as high power pump modules with optically pumped thin disk gain media in industrial applications (perportedly a Trumpf model)


thus there is a hand wavy, but not easily disregarded, "pathway" to take a cheap, but alarmingly powerful, laser with all of the control and power electronics, and couple the light into a gain medium that is suited for pumping at 808nm.

it would be more appropriately compared to an arc lamp (a CW variant of a flash lamp), lacking any way to generate a thermal lense.

I am even imagining that a higher doping concentration in NdGlass might be the preferrable choice if the element could be obtained without considerable cost.



I am wondering if there is anything wrong with this skeletal, and perhaps pipe-dreamy, analysis. Again:

I am already aware that this is "Way out there" and not following any guide or readily available technique or approach that could be referenced with instructive information.

it would be a complete "McGuyver" job. there is the upside of the sheer brute force that comes from such a powerful pump source.

but again: The incentives and economic efficiences don't necessarily correlate with "best practices" or "standard approach" or "following the well worn path"

[mixedgas]

There is nothing to be gained over ripping out the diode bar from the IPL and putting a cylindrical lens or a corrector in front of it.

M`2 of the IPL corrected beam is horrible. Due to the laws of thermodynamics , start with bad beam, get less etendue at target.

Getting a good pump, requires, to a certain extent, imaging the diode die into the lasing medium. Breaking up and enlarging the image of the die can really hurt you in terms of diffractive loss.

Can you end pump a very short lasing medium with the IPL exit light and a downcollimator or F1 lens, well maybe yes. Does it become efficient? Likely not.

The length of the beam waist in the medium matters. That is massively dependent on your optics train. Without accurate modeling of the whole optics train, it's a folly.

Corrected Diode arrays are cheap on Ebay. Seller "Starlight Phontnics" screens them for wavelength.

Good pumping is at 805-808;for out of band pumping. Get a common 820 or 840 nm diode and your out of the pump adsorption curve or at its very edge. Where do you think the wafers with "off" doping or epitaxy go? They're diced, coated, graded, tested, and used.

Ripping the diode driver out of the IpL may or may not be practical. Depends on how the diode array is wired. Series, or parallel etc.

in other words, your answer is highly situational. Can you? Maybe. Should you? Probably not unless you have money to throw away.

Every part in the chain has a transfer function. Optimizing all those functions in series is critical.


Steve