PSEUDO-RANDOM MODULATED DIODE LASER FOR TIME RESOLVED FLUORESCENCE SPECTROSCOPY

THIS PROJECT PERTAINS TO THE DEVELOPMENT OF A NOVEL, COST EFFECTIVE,COMPACT SENSOR FOR TIME RESOLVED FLUORESCENCE SPECTROSCOPY OF BIOLOGICAL SAMPLES. THE SENSOR HAS HIGH-TIME RESOLUTION (SUB-NANOSECOND) FOR ACCURATE FLUORESCENCE DECAY TIME MEASUREMENTS WITH HIGH SENSITIVITY. THE SENSOR IS BASED ON THE PSEUDO RANDOM CODE MODULATED (PRM) CW LIDAR TECHNIQUE WHEREBY THE FLUORESCENCE SIGNAL FROM THE PRM LASER EXCITATION IS DETECTED BY A RECEIVER SYSTEM, AND PROCESSED USING CROSS CORRELATORS TO DETERMINE THE DECAY PROFILE IN REAL-TIME. THE TIME RESOLUTION OF THE MEASUREMENT IS ENHANCED BEYOND THE QUANTIZATION PRECISION OF THE DIGITIZER USING A PROPRIETARY RESOLUTION ENHANCEMENT TECHNIQUE. THE SPECTRAL INFORMATION OF THE FLUORESCENCE SIGNAL IS OBTAINED USING A SET OF INTERFERENCE FILTERS. THE DETECTABLE SIGNAL IS NOT LIMITED BY THE BACKGROUND NOISE LEVEL DUE TO THE INHERENT CHARACTERISTIC OF THE PRM PHASE SENSITIVE TECHNIQUE. A PROOF OF CONCEPT EXPERIMENT, CRITICAL SYSTEM ANALYSIS, AND CONCEPTUAL SYSTEM DESIGN IS BEING CARRIED OUT. THIS SENSOR CAN BE USED FOR THE IN VIVO AS WELL AS REMOTE MEASUREMENT OF THE FLUORESCENCE SIGNAL FROM SAMPLES IN REAL-TIME.