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IPL reflector research


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Q. Hello everyone, I need to replace a ceramic reflector in a Intense Pulse Light (IPL) machine with a metal reflector and I have been looking into electroplating gold, silver or rhodium for my reflective surface. the question is, does anyone have any information on this metals reflectivity index in a graph. Thanks in advance for your help.

Leo Berganza
R&D - Newport Beach, California


A. Lots of reflectivity info available on the Internet. What wavelength and operating environment?

Aluminum (vacuum deposited) and silver are commonly used reflectors. Aluminum is best for far-UV & UV, silver is best for visible & IR. Unless used in vacuum or inert gas, both are usually given protective, transparent oxide 'dielectric' coatings. Aluminum is sometimes used uncoated, as in large reflector telescopes (in locations with clean, dry air), but then stripped and recoated every few years.

For high reflectivity over the entire UV to IR range, with scratch and tarnish protection, the following composite coating is suggested:
Al (base coat), 14 nm thick alumina (diffusion barrier), 25 nm Ag, 110 nm alumina, 140 nm layer of Sb2O3 or TaO3 (top). Optimal layer thicknesses are a function of wavelength; these values are for 550 nm light. From work by Nikos Drakos (University of Leeds), Ross Moore (Macquarie University, Sydney) and James R. Graham (UC-Berkeley).

For uncoated precious metals, rhodium is ~usable at low wavelengths (below 550 nm, green light) although not nearly as good as Al. Gold is good at higher wavelengths, as good as silver for IR and above.

Ken Vlach [dec]
- Goleta, California

contributor of the year Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.


Gold reflectors

January 15, 2018

Q. What is the solvent used for gold nanoparticles to carry UV and in which NM it shows peak?

muthu lekshmi
- kk dist tamil nadu INDIA

January 2018

? Hi Mithu. Please get back to us with at least 3 or 4 times as many words ...

... who you are, what you're trying to do, why, etc. Sorry, I have no idea what this question is about. Thanks!


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Ted Mooney, P.E. RET
Striving to live Aloha
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