The present application discloses a tissue oximeter system which includes radio frequency (RF) wave sources configured to produce RF waves at different RF frequencies, near infrared (NIR) light sources each configured to emit NIR lights each modulated by one or more of the RF waves generated by the RF wave sources, an optical probe that directs the NIR lights modulated at different RF frequencies to a living tissue, and wherein the optical probe includes a plurality of light-emitting points that each can couple one of the NIR lights into the living tissue, one or more optical detectors that each can receive scattered lights from the living tissue and to convert the scattered lights into electronic signals, and a control and data acquisition unit that can calculate absolute level of [HbO], [Hb], or [SO2] based on the electronic signals.
