The DHSPI (Digital Holographic Speckle Pattern Interferometry) systems have been developed and continuously optimized at IESL-FORTH with the aim to investigate and monitor deformation, deterioration, and fracture mechanisms and thus to evaluate the structural condition of materials and systems as a result of ageing, mechanical alteration and materials’ failure.
DHSPI captures microscopic alterations of sub-surface topography on the basis of high-resolution interferometric imaging. Hidden defects are revealed as visible interference fringe patterns forming locally inhomogeneous intensity distribution patterns. The deformation data are extracted through the differential displacement of the surface under investigation and the deformation value is measured by multiples of half wavelength.

DHSPI-II, the most recent model, is a compact fully portable system with a built-in data acquisition and processing unit and dedicated user-friendly software, for the system control and data post-processing which enables real-time qualitative and quantitative structural diagnosis. DHSPI-II also allows control (via cable) from a remote pc (eg laptop) which provides extra flexibility for in-situ measurements. 

TECHNICAL INFO:  •Laser power: 300mW     •Coherence length: >30m     •CCD resolution: 5MP    •Spatial resolution: 144 lines/mm     •Displacement resolution: ≥ 266nm    •Sensor lens: C-Mount type exchangeable   •Beam Divergence: >40cm@1m (Gaussian Profile)