We propose to construct a pre-commercial microsecond-resolved, spectrally broadband, ellipsometer, based on our recently-developed, ERC-funded technique of cavity-ring-down ellipsometry (CRDE), for which we have a US and international (PCT) patents pending.This BIOCARDE instrument will have unprecedented time resolution and sensitivity, compared to commercial ellipsometers, and will have potential application in the biosensing and surface characterization (semiconductor) industries.The BIOCARDE instrument will be tested by the Biosensors group at FORTH (Prof. Gizeli), and by our industrial partners SOPRALAB in Paris (world-leading ellipsometry company).Interest in the instrument will be from three directions:1) Research groups in the biosensing and surface characterization fields. Instruments will be sold to these groups, which will increase the profile and research scope of CRDE.2) SOPRALAB, is interested in the enabling technologies of the instrument (the combination of the broad-band laser and microsecond-resolved data acquisition)3) Biosensing companies, as the BIOCARDE instrument will be made to be compatible with (and tested with) their commercial prisms and biosensing delivery systems, to prove that the new capabilities (microsecond ellipsometric detection) is compatible with their existing technologies.