Modern Optical Measurements: An Introduction with Practical Applications

Level: Introductory Length: 4 hours Format: In-Person Lecture Intended Audience: Engineers, technicians, managers, and scientists who wish to learn more about fundamentals of optical measurements for different applications. Basic knowledge in optics is assumed. Description: “The best remedy against hallucination is measuring” [Plato, 427-347 B.C.]. Thus, measuring is necessary to describe and quantify a physical quantity. Optical measurements require care since they can be used to characterize small distances and, hence, are sensitive to disturbances. In addition, measuring involves many hints and tricks to obtain reliable, repeatable quantities. This course teaches fundamentals of modern optical measurements. We begin with basics such as refractive index measurements and integrating sphere operations (infinite sum of reflected beams…). Next, measurements of external transmission, internal transmission and transmittance are explained. Afterwards a goniophotometer and an x-y stage for numerical aperture (NA) or light distribution curve and laser beam diameter measurements are shown and described. This is followed by the basics of spectral measurements—including how a monochromator works--and finally interferometric measurement techniques are explained. The course discusses how many repeated measurements are needed for reliable, statistically significant results and what statistical data should be provided to fully characterize a measurement. In reference to essential/relevant applications the individual advantages and drawbacks of various methods are described. Anyone faced with the question “How can I do basic optical measurements?” or “How reliable is my measurement result?” will benefit from this course. The applications section will provide best practice examples for optical measurements on LEDs, lighting and/or displays. Learning Outcomes: This course will enable you to: - explain how an optical power measurement is done (integrating sphere with infinity sum of reflections) - distinguish between measurements of direct transmitted light and scattered transmitted light power - explain how to measure transmission of a plane parallel glass plate as in the case of optical filters - distinguish between internal transmission, external transmission and transmittance of light power - describe how a refractive index measurement is done - discuss the purpose and key components of a goniophotometer, how to use this instrument to measure the angular distribution of light power and how to use this measurement for light sources like LEDs - demonstrate the working principle of a light distribution (transversal distribution) measurement set-up (x-y stage) and use it for laser beam profiling and for NA measurements - apply and discuss what a power spectrum is and how it is measured (monochromator, spectrometer) - describe how to calculate photometric quantities based on physical quantity measurements - explain the basics of an interferometer - present measurement results and their uncertainties in a statistically valid fashion - describe the physical fundamentals of optical and photometric measurements - identify advantages and disadvantages of different measurement set-ups - demonstrate typical applications of optical measurements for precise length measurements - demonstrate typical applications of color and light distribution curve measurements - conduct optical power measurements for LEDs and diode lasers Instructor(s): Steffen Reichel has been a full time chair and professor for measurement and photonics at Pforzheim University, Germany since 2016. He studied electrical engineering at the University of Kaiserslautern and at Michigan State University, MI, USA. After receiving his degree in 1996, he worked on his doctorate in the field of optical communications at the University of Kaiserslautern. In 1999 he joined Lucent Technologies and worked on fiber optical communications, erbium-doped, and Raman amplifiers. From 2001 to 2016 he worked for SCHOTT on several fields of optics including imaging optics, fiber optics, waveguide optics, laser optics, illumination optics, optical measurements, and optical filters. He is a Fellow and Senior Member of SPIE, a Senior Member of IEEE, and in 2013, became honorary professor for Optics & Photonics at the University of Applied Science, Darmstadt, Germany. He has authored 3 book chapters and ~70 publications, and has 22 granted and applied patents. Karlheinz Blankenbach graduated in physics at the University of Ulm, Germany, where he also received his PhD in 1988. Until 1995, he was with AEG-MIS /subsidiary of DAIMLER-MERCEDES), Germany, developing display electronics, LCDs and software. A highlight was a 3D helmet mounted monitor for stereo endoscopy founded by BMBF. Karlheinz was appointed in 1995 as full professor at Pforzheim University, Germany, launching the University's Display Lab. His main R&D activities are on optical display measurements (mainly automotive, incl. LEDs) and display systems as well as display hard- and software resulting in many talks, papers (~200), and projects (governmental and industrial funded). Karlheinz is member of the SPIE’s Photonics West committee on “Advanced in Display Technologies” and vice chair of Society for Information Display’s subcommittee “AUTOMOTIVE/VEHICULAR DISPLAYS AND HMI TECHNOLOGIES”. He has been a member of the board of the DFF (German Flat Panel Forum) since 2001 and has been Chairman since 2011. Karlheinz is also Chairman of the Electronic Displays Conference held every year in Nuremberg, Germany. Event: SPIE Photonics West 2020 Course Held: 04 February 2020