Oxylase--Low Cost, on Airway, Fast Oxygen Sensor

We will develop ultra-compact arrays of multi-wavelength diode lasers that have excellent beam quality for use in ophthalmology and other medical imaging applications. The arrays are based on vertical-cavity surface-emitting lasers (VCSEL). Unlike conventional diode lasers, VCSELs emit low-divergence, circularly-symmetric beams which are free from astigmatism and ideally suited for imaging applications. The targeted configuration is an array of VCSELs, each with a different wavelength, which are efficiently combined and fed through an optical fiber into a scanning laser ophthalmoscope (SLO). Our design maintains constant alignment of the source with no moving parts and allows rapid, programmable electronic switching between the lasers. We have several goals for Phase I: 1) produce VCSELs to be used in a SLO to demonstrate their suitability, 2) evaluate the performance of the VCSEL- equipped SLO, 3) determine the extent of wavelength variation which is feasible for a single chip, 4) investigate techniques for mounting and aligning multiple laser chips on a common substrate, 5) determine the optimal means for combining the beams, 6) survey the range of other medical imaging applications and requirements for similar arrays, and 7) report our results and plan construction and implementation of the wavelength-multiplexed source array for Phase II.