Please register with

(for food estimate – last minute walk-ins are completely welcome)

Ventura OSA


Co Presidents

Virginia Ford

Eric Ford


Vice President

Patrick Ford



John McDonald



Fred Houston



John Tardif


Arrangements Chair

Fred Houston



Ventura OSA Announcement for

February 20, 2018  

(Please RSVP)


Phosphors in White LEDs


Ram Seshadri, PhD


This talk will cover the key role that phosphors play in the now mature solid-state white-lighting technologies based on combining a III-nitride-based near-UV or blue solid-state light source with down-conversion to longer wavelengths.  Almost all widely used phosphors comprise a crystalline oxide, nitride, or oxynitride host that is appropriately doped with either Ce3+ or Eu2+. Optical excitation into these states and concomitant reemission can be tuned into the appropriate regions of the visible spectrum by the crystal these ions are hosted in. Experimental studies of some of the best phosphor materials, employing state-of-the-art structural tools, have yielded guidelines for what are desirable structural features. We find that a useful sorting diagram for efficient hosts with high quantum yield has the band gap of the host – readily calculated with high reliability using hybrid functionals in DFT – as one of the axes, and the calculated Debye temperature as the other axis.

    Venue For Event

Advanced Spectral Technology, Inc.

94 W Cochran St Suite A

Simi Valley, CA 93065


GPS Lat/Lon: 34.282265, -118.799712

6:00p Mixing and Stand Up Dinner

7:00p Speaker


$20 donation on site (it is a donation

for food, insurance and venue. If you

need a no-food, student, old age or

other discount please give yourself one).


About the Speakers:

Ram Seshadri, PhD

Materials Department and Department of Chemistry and Biochemistry

Materials Research Laboratory, University of California

Santa Barbara CA 93106

Ram Seshadri is the Fred and Linda R. Wudl Professor of Materials Science and Director of the Materials Research Laboratory at UC Santa Barbara. He received his PhD in Solid State Chemistry in 1995 from the Indian Institute of Science, Bangalore, and after some years as a post-doctoral fellow in Europe, returned to Bangalore as an Assistant Professor in 1999. He moved to UC Santa Barbara in 2002. His research work, embodied in 300+ publications, addresses the topic of structure-property relations in crystalline inorganic materials, with a focus on materials for energy applications. He is a Fellow of the Royal Society of Chemistry and of the American Physical Society. He has served on the Editorial Committee of Annual Reviews of Materials Research since 2008, and as an Associate Editor of Chemistry of Materials since 2015.


 From Eric & Ginny



Due to mud slides last month, this presentation was postponed until February 20th.  We hope that will work for you, hope to see you at the meeting and look forward to learning about LED Phosphors.

The Ventura section of the Optical Society of America promotes optical science and optical engineering and facilitates communication and networking among optics professionals, students, and optics aficionados in the geography reaching roughly from Santa Barbara to Pasadena.

Upcoming dates:

  • March 13th: John Tamkin on Image Testing of Small Sensor Hyperfield Cameras

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