ME Graduate Seminar Series: Measurement of Shapes, Vibration Amplitudes and 3D Refractive Index Distribution of Transparent Objects

Wednesday, April 24, 2019
10:00 am to 10:50 am
Floor/Room #: 
218

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WPI ME Graduate Seminar Series 2018-2019


Advanced Optical Metrology:

Measurement of Shapes, Vibration Amplitudes and 3D Refractive Index Distribution of Transparent Objects

Pavel Psota
Assistant Professor, Technical University of Liberec
Department Head, Optical Measurement Methods and Metrology, TOPTEC

10:00-10:50 am, Wednesday, Apr. 24
Higgins Labs 218


TOPTEC (The Research Centre for Special Optics and Optoelectronic Systems) and Technical University of Liberec (Czech Republic) are ones of the European leaders in the field of research and development of super precision special optics and metrology. The talk will focus on recent R&D projects focusing on optical measurement methods, in particular interferometry and digital holography.

Interferometers in general are understood to belong in the group of the most accurate measurement devices. Their fundamental measure is the wavelength of light and todays interferometers can resolve even fraction of wavelength thus their sensitivity is outstanding. However, due to bounded nature of a light wave, the measurement range given by the unambiguity is squeezed within the range of one cycle of the wave. Measured phase maps are therefore wrapped within the range of 2π radians that brings some limitations in many applications. This drawback is evident e.g. in the field of aspherical and freeform optical surfaces measurement. Nowadays, a lot of effort is therefore put into R&D of metrology for complex optical surfaces and one of the promising direction (multiwavelength sweeping interferometry and digital holography) will be presented.

The talk will also mention non-standard interferometric techniques for 3D measurement of phase (transparent) object. Specifically, investigation of 3D temperature field around synthetic jets, 3D visualization of domain walls structure within ferroelectric materials or lab-on-chip approach will be introduced.

Research of PZT transformers and noise shielding system based on macro-fiber-composite actuators requires accurate measurement of vibration amplitudes over the whole surface with large dynamic range. Last part of the talk will be devoted to frequency shifted time average digital holography with phase modulation that enables to measure vibration amplitudes in range from tenths of   nanometers up to several tens of microns.

About the Speaker

pavel 1

Pavel Psota, assistant professor at Technical University of Liberec and head of department of Optical measurement methods and metrology at the Research Centre for Special Optics and Optoelectronic Systems (TOPTEC), has worked on various interferometric measurement techniques for over 10 years. In 2015 he completed a PhD in Applied Sciences at the Technical University of Liberec with thesis on investigation of vibrations by means of time average digital holography. He is has published more than 20 journal papers and more than 50 conference proceedings; he owns one patent and some others intellectual property results. He has participated on many international projects including projects for ESA (European Space Agency). His recent research is focused on the development of digital holographic or interferometric methods for temperature fields measurement including holographic tomography for 3D fields, characterization of internal structure of ferroelectrics by means of digital holographic microscopy/tomography and his current effort is mostly concentrated on absolute measurement by interferometry and digital holography using multiple wavelengths and interferometric methods for measurement of aspherical and freeform optical surfaces.

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