July 7, 1999

Dr. Mike Pelletier

Principal Applications Scientist

Kaiser Optical Systems, Inc.

371 Parkland Plaza

P.O. Box 983

Ann Arbor, MI 48106

Dear Mike:

We have been reading over the notes of our visit last week, and I wanted to pose a few questions that I will telephone you tomorrow (Thursday) afternoon to discuss. We will pass along this information to our colleagues at Monterey (MBARI).

--We are trying to compare the instrumental throughputs of the Raman systems that we tested (yours, Instrument SA, InPhotonics). Because there are several elements of the system that can cause absorption and other forms of signal attenuation, we wanted to look at them individually, if possible. Can you tell me the throughput/dispersion efficiency of your transmission gratings? What about the over-all throughput of laser light through the probe head (i.e., light out/light in)? Have you compared your throughputs with those of the instruments or gratings made by other companies?

--We are still considering how to handle MBARI's needs for about 2 cm-1 resolution for two of its most immediate projects. Here are the 2 possibilities that we are considering with respect to your instrument: 1) purchase a CCD with double the normal number of channels/pixels, 2) use your normal CCD and normal gratings for the reconnaissance Raman work, but use higher-
resolution (smaller spectral window) gratings on days when the project demands them.

Can you please advise me on those two options? What are the prices of additional higher-resolution gratings? What kinds of spectral windows can they accommodate? Are any of your customers using a 2000-channel CCD? Does your software readily support such a detector?

--Is your MICROPROBE (laboratory system) confocal? How is that confocality engineered into your system?

--Am I correct that one readily can change from a multimode input fiber (as we probably would use for the underwater research) to a single-mode input fiber (as probably desirable on the microprobe lab system) very easily? At what expense?

--If MBARI bought a fiber-optic-based system from you that was optimized for use with the 532-
nm laser, which components would have to be changed if the laser wavelength were changed?

How expensive would that be? Would those changes require that the spectrometer be sent back to Kaiser?

--Assuming that we required a fairly standard Raman system (spectrometer, probe head, immersion probe, 532 nm laser (100 mW), standard CCD, microscope system, spectral mapping capability), what is your estimated delivery time?

We also would like to send you next week a few more aqueous solutions to run with your immersion probe. These tests would give us a better idea of the limits of detection of your probe for anionic complexes dissolved in seawater or somewhat "concentrated" seawater.

After we get the above information, I will send you a list of specifications of the Kaiser system that I think will best fit MBARI's needs. If you have any additional suggestions about the best instrument configuration to carry out the oceanographic studies, please let me know. We need an official quotation for the system that I will specify.

I will telephone you Thursday afternoon to discuss the questions above. There is no problem if you need more time to look into some of the questions. Thank you again for your help.

Best regards,

Jill