Sarah is a leading authority on technical training and process improvement for the photonics industry. She has successfully developed and launched technical training courses and certification programs for the photonics industry since 1999 and her Laser Technology Series program currently has more than 10,000 corporate trainees on-course via corporate intranet learning systems. Some of her clients include Spectra-Physics, Coherent, KLA-Tencor, Carl Zeiss Meditec, JDS Uniphase, Lightwave Electronics, SPIE, NASA, The Boeing Company, Northrop Grumman, Wylie Labs, Canesta, Rockwell Collins, the USMC, and the USAF.

Sarah began her career in 1986 as a co-op student working in the Solid State Laser Materials Lab at the NASA Langley Research Center, where she was part of the team that developed titanium-doped sapphire as a laser medium. She has also held research and management positions at The Analytic Sciences Corporation (TASC), where she worked at Brooks Air Force base on eye-damage studies and laser-eyewear development, and Lightwave Electronics as a manufacturing supervisor of diode-pumped solid state lasers. In 1999, Sarah started a training company to help Silicon Valley laser manufacturers train their technical workforces in the fundamentals of lasers and optics, including optics inspection, handling, and cleaning, optical alignment, and geometric optics. Her newest venture is a consulting firm that helps photonics companies improve their bottom lines through corporate audits of critical processes and implementing in-house certification programs.

Sarah received degrees in applied physics from Old Dominion University (Hampton, VA) and the University of Texas (San Antonio, TX), and in philosophy from DePaul University (Chicago, IL). Sarah is also a CAT I and CAT II certified laser safety officer.

12/3/08

The most important thing about handling optics is to minimize, minimize, and minimize handling them! Because of their delicate coatings and our capacity to contaminate and chip them, the more we handle an optic, the better chance we have of damaging them.

Of course, there are the basics of handling them; always work on optics under a flow hood, if possible, never transport an optic without it being covered, always work with optics on a pad of cleanroom approved wipes, never handle optics with your bare hands, always wear powder free latex gloves (I’ll suggest some other gloves in a minute), only hold optics by their ground (outside) edge, and never, ever touch the optical surface. Our skin produces an oily substance called sebum created from our sebaceous glands that mixes with sweat and lubricates our skin…remember when you were a kid and stayed too long in the bathtub and got “prune” hands? It’s the sebum that keeps our skin from absorbing water.

Fingerprints etch optics

Without going into the complete chemical breakdown, sebum is basically a combination of acids and hydrocarbons. Acids will “etch” coatings, and hydrocarbons are basically an oily substance that is hydrophobic (repels water). Try it sometime on an already damaged optic…put your fingerprint on it and then inspect it with 10X magnification. You will be able to see the beads of oil forming your fingerprint. Leave your fingerprint on it for even longer and you’ll be able to see the etching into the coating. Please don’t do this on a useable optic!

I think in my optics lifetime, I’ve only been able to actually save a couple of optics when I accidentally touched their optical surfaces or dropped one. Contaminated gloves will do the same thing. Remember the rule of thumb about changing gloves that we talked about last week? Change them often, because they are way less expensive than the optics you’re working with!

When you think about it, most optics go into very expensive tools…semiconductor equipment, lasers, telescopes,and so on. Did you know that a fingerprint can continue to outgas for up to 30 days? Not only are fingerprints difficult to remove (I promise we’ll spend a lot of time talking about cleaning optics soon), they can be deadly to a multimillion dollar tool when it’s at your customer and the film contamination from your fingerprint absorbs the light energy and burns or degrades the optic’s performance and renders the tool out of commission. An unhappy customer will look for another vendor, or at least, will be very upset when they’re losing money every day the tool is not producing. Or there’s the poor scientist who waited months for his laser to do his research and now the laser is not performing to specification because of a fingerprint.

When I supervised laser manufacturing, it was a serious matter to get a laser back only to find that someone’s fingerprint had caused the problem. I used to joke with my manufacturing staff that I was going to fingerprint each of them, so that I could forensically identify whose fingerprints were on the optics. Of course, that sent HR into fits, but the point is the worst thing you can do is to accidentally touch the surface of an optic and not do anything about it. It happens to all of us one time or another, but to let it pass through the manufacturing process is worthy of a lashing :-). I’m kidding about the lashing, but it definitely means that you need more training and practice if you are guilty of letting fingerprints pass through the process. This includes uncoated optics as well, especially prior to going into the coating chamber.

Polyester-knit gloves

One common complaint I hear from practitioners is how much their hands sweat when wearing latex gloves. It’s true, very uncomfortable, and makes changing gloves almost impossible. There are several options: you can double- or triple-glove, as I suggested last week; you can wear cotton gloves under the latex, if allowed; or you can wear some of the new polyester-knit gloves designed specifically for working with optics. My newest favorite is called the Opto-Glove from Opto-Alignment Technology (Indian Trail, NC). They “combine contamination control and electrical dissipation properties in a 100% latex-free glove. The polyester knit construction is soft and non-damaging to delicate optical components. The gloves are lint-free for use under laminar-flow hoods and cleanrooms to class 100.”

These gloves can also be professionally washed. Because they are more expensive than latex gloves, I typically recommend using them only when actually handling the optics, but often wear them over my latex gloves when I’m working on opto-mechanical assemblies and then remove them when handling anything non-optical. Many companies have problems with the expense of specialized gloves, so don’t expect your buyers to have them as standard stock anytime soon. But, if you’re working in an area where it makes sense, especially with UV radiation (latex gloves outgas and can cause photocontamination), I suggest you do your homework and state a strong case. And then make sure they get cleaned by your cleanroom-garment cleaner on a regular basis with a low-sudsing cleanser.

Packaging

I want to end this discussion by mentioning a topic that we’ll soon spend an entire blog talking about: packaging. I’m so disappointed in most of the packaging that the optics manufacturers use that I believe it deserves an entire discussion. I was recently with a client who had carefully wrapped a hundred optics, which were unwrapped by the customer, only to be rejected, and then all had to be rewrapped by the customer and sent back to the vendor to be unwrapped again! Not only was it difficult to tell where the damage happened, the direct labor cost of wrapping and unwrapping these hundreds of optics was expensive for both parties. I believe this topic is so important that I want to talk about it next time, so we’ll save inspecting optics for a later date. I’ll tell you what I would like in an optic’s package, and we’ll see if we can meet somewhere in the middle. But, I also believe that when it comes to handling optics, the packaging is one of the biggest problems our industry has! Talk to you soon!

Just wanted to call your attention to a great product I found. It replaces fiber optics cables with free space optics technology.

The Canon Canobeam is essentially a wireless fiber optic cable that transmits data, voice, and video communication accross short distances.

I found a great individual website about it at

www.freespaceoptics1.com

I thought some would find it interesting. We currently use the Canobeam and have had great results.

Wed Dec 10, 02:36:00 PM CST