We report the development of a simple commercial digital holographic microscope. The hologram is recorded using a CCD sensor and numerically reconstructed to provide quantitative analysis of the object. The laser source is coupled via fibre optics and the opto-mechanical setup is flexible and customizable for either the reflection or transmission mode. The user-friendly software allows live reconstruction, simultaneously providing both the amplitude and phase images. System performance is improved with phase unwrapping and interferometric comparison. Additional features include various image enhancements, cross-sectional and line profiling, measurement and data analysis tools for quantitative 3D imaging and surface topography measurement. The performance of the product is tested on different micro devices, glass and silicon surfaces.

The inspection and characterisation of laser marks using digital holographic microscopy (DHM) is presented in this paper. A DHM system in transmission mode was designed and the reconstruction algorithm for this configuration was investigated. The software was developed to provide live reconstruction of holograms for real time numerical evaluation of amplitude and phase contrast images. A CO 2 laser-based marking system was employed to create marks on glass substrates. By analysing the quality, 3D profile measurement, and material distribution of the marked area, the parameters of the laser system could be optimised to achieve the desired mark. The phase contrast images provide quantitative refractive index analysis and 3D profile studies. The results were compared with those obtained using white light confocal microscopy. The capabilities and advantages of the DHM system for the analysis of laser marks are also presented.