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 camera based 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.

I worked with industries in several European and national resesarch projects, such as DIMES and MOTIVATE.

Latest scientific achievements include the realization of high-resolution THz holography, THz ptychography and Talbot imaging using a far infrared gas laser and an uncooled microbolometer. I also established the generation and observation of Orbital Angular Momentum states in the THz domain.

Industrial assignments

I strive to apply the optical methods to industrial problems. For many years imaging methods were accreditated according to ISO 17025 , including 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
  • development of integrated sensors for Airbus: DIMES project

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

Present Positions

Senior Scientist at Empa

Lecturer at ETH Zurich

Member of Empa's Research Commission

Editor in Chief of „Optics and Lasers in Engineering“


Senior Member of Optica (formerly known as OSA)

Member of European Optical Society (EOS), and its national chapter SSOM

Member of the Physical Society of Zurich

Elected Honorary Member of the Swiss Society for Non-Destructive Testing (SSNT)