This proposal pertains to the development of a prototype sub-nanosecond resolution optical sensor utilizing Pseudo-Random Modulation (PRM) Correlation technique for time resolved fluorescence or photon migration measurements. The results of the Phase I proof-of-concept experiment and accompanying simulation studies clearly demonstrated the powerful capabilities of the technique for time resolved measurements. The validity of the Time Resolution Enhancement Technique was verified in both fluorescence and photon migration experiments. In addition, a new method for correcting waveform deformation due to the signal droop, is developed by using an ad-hoc reference code which is simply the measured pump source waveform. Combining the powerful PRM-Correlation method with the ad-hoc reference code and the Resolution Enhancement Technique, a simple, cost effective fluorosensor with sub-nanosecond time resolution is now conceptualized. In Phase II, a prototype sensor for photon migration measurement with 50 psec resolution will be developed, and the system will be tested for the measurement of time resolved reflectance from a simulated tissue sample to retrieve the relevant parameters of the sample. In addition, research for development of viable blue laser sources for PRM-Correlation fluorosensor will also be performed.
