A Modular, Multiwavelength, Wideband, Intensity Modulated Optical Spectrometer for Localised Near Infrared Spectroscopy

摘要

We describe the development of a modular, ultiwavelength, wideband intensity-modulated near infrared spectrometer (100MHz-1GHz) capable of simultaneous measurement of three parameters - the dc intensity, the ac intensity and the phase shift of light transmitted through tissue at a high sampling rate. The intended purpose of this instrument is the detection of fast dynamic changes in the reduced scattering coefficient of tissue due to cellular depolarisation. The instrument requires sensitivity to small changes in optical pathlength and absorption in small volumes of tissue.