Design of a dispersive lateral scanning surface profilometer

Non-destructive testing and online measurement of surface features are pressing demands in
manufacturing. Thus optical techniques are gaining importance for characterization of complex
engineering surfaces. Profilometers based on the laser scanning confocal microscopy can provide
non-contact, fast measurement with high lateral and axial resolution. In this work we present the
optical design of a lateral scanning probe using a broadly tuneable laser (1500-1600 nm) source in
the IR region using Zemax optical design software. The optical probe being one of the main
constituents of integrated optic measurement system critically determines the performance of the original metrology sensor system. Various approaches of reduced device dimension have been
investigated without compromising the optical performance enabling the probe system suitable for
embedded metrology application. The optimization and analysis revealed that the diffraction limited
imaging resolution can be achieved using simple achromatic relay lenses and the objective over the
entire field of view.