Personal Homepage of Erwin Hack

Erwin holds a diploma in Theoretical Physics and a PhD in Physical Chemistry, both from the University of Zurich. He joined Empa to build up a laboratory for optical measurement methods and established Speckle Pattern Interferometry, Fringe Projection, Thermal Stress Analysis, THz Imaging and Spectroscopic Ellipsometry. He develops and applies these methods in research projects and industrial assignments.

Research topics

I started my career at Empa with electronic/digital speckle pattern interferometry. My scientific achievements include the realization of a phase stepping procedure in the synthetic wavelength of a two wavelength interferometer; quantitative 3D strain analysis from multiwavelength shearography; the creation of superspeckles with an increased correlation length; the reduction of speckle noise using LCD based adaptive optics; and the realization of an imaging fibre bundle DSPI for microelectronic applications. In parallel, I have studied general aspects of camera-based instrumentation: I derived a first order unification of common contributions to the measurement uncertainty of linear and Carré-type phase stepping procedures.

I have been involved in the development of calibration artefacts for full-field optical measurement systems, as well as their application in the validation process of Finite Element Model simulations, which has culminated in a CEN workshop agreement that is being transformed into a CEN Technical Report.

Latest scientific achievements include the realization of high-resolution THz holography and THz ptychography using a far infrared gas laser and an uncooled microbolometer.

Industrial assignments

I always strived to apply the optical methods to industrial problems and succeeded to get my lab accredited according to ISO 17025, including the DSPI and fringe projection systems. Representative applications were

  • testing of the European Robot Arm for the International Space Station
  • accuracy assessment of laser scanners used in railway track engineering
  • deformation analysis of high-precision balance mechanics

For the optics and coating industry, I assess coating layer thickness and optical parameters using spectroscopic ellipsometry. The results are used in quality control and development of sensors, protective coatings and solar cells.

Present Positions

Senior Scientist at Empa

Lecturer at ETH Zurich

Member of Empa's Research Commission

Vice-president of the Swiss Society for Non-Destructive Testing

Editor in Chief of „Optics and Lasers in Engineering“


Senior Member of OSA

Member of EOS, and its national chapter SSOM

Member of the Physical Society of Zurich