Vertical-cavity surface-emitting laser (VCSEL) sources for frequency domain photon migration

Frequency domain photon migration (FDPM) uses modulated laser light to measure the bulk optical properties of turbid media and is increasingly being applied for noninvasive functional medical imaging. Though semiconductor edge-emitting laser diodes (EELs) have been traditionally used for this application, we show that VCSELs exhibit performance characteristics suitable for FDPM measurements of tissue optical properties. Their output power and modulation characteristics are more than sufficient for optical property recovery. In addition, their small size, high efficiency, low cost, and simple packaging make them an attractive choice as components in clinical FDPM systems. We demonstrate a unique, compact optical probe that was enabled by VCSEL technology.