Systems, devices, and methods for identifying a target in vivo are disclosed. A target identification system for use in electrosurgery includes a probe, an optical splitter, and a spectroscopy system. The probe includes an optical pathway to pass a first optical signal to an anatomical target and at least a portion of a second optical signal from the anatomical target. The optical splitter includes a first port to direct the first optical signal to the optical pathway and to receive the at least a portion of the second optical signal from the optical pathway, a second port to receive the first optical signal, and a parabolic reflector to redirect the portion of the second optical signal. The spectroscopy system can identify a characteristic of the anatomical target based on the redirected at least a portion of the second optical signal.