My name is avi schiff and i am the technical director at arsuf lasers.
In this video I would like to share with you our experience in manufacturing laser rods to the medical and cosmetics market.
As output power of these machines is steadily increasing, damage is increasingly prevalent. The LIDT value denotes the max power density that the rod face can withstand without damaging.
The defense applications market is using NS to use pulses compared to ms pulses in dermatology one, and the laser damage considerations are not exactly identical. Long millisec pulses we tend to simulate as a CW model where damage could be either dielectric to the coating layer or thermal one to the material face.
To cope with the high power absorbed by the coating some would go for a double layer or more. It could work and looks like a good solution but degradation will be fast. The interlayer bonding within the coating layers will break and there is more compressive stress on the surface.
Amorphous materials such as glasses all of them have defects that can grow into failure, the pulsed damage mechanism is wholly dependent on bonds breaking, dependent itself on the rate of energy (power per unit area) delivered. Heat dissipation is not a primary factor.
When we got exposed to the medical and cosmetics market, we found our customers using erbium rods with very poor coating despite the fairly low lidt value given in the specification. Batches would either fail at the qc acceptance stage or after a short use. Moreover, a single coating damage can lead to system wide failure.
Our manufacturing is traceable from the material growing to final coating and after analysing our customer’s laser hot spots we then design hard coating mostly with double margin to ensure zero failures and long life of operation.
In the picture you can see an example of erbium rods with very poor coating one of our customers was receiving.
And another image where you can see our erbium coated rods how they look.
This is for now. Anyone who wants to consult with us is invited