Systems and methods for performing RF ablation while monitoring the procedure using low coherence interferometry (LCI) data are described. A catheter includes a distal section, a proximal section, a multiplexer, and a sheath coupled between the distal section and the proximal section. The distal section includes one or more electrodes configured to apply RF energy to a portion of a sample in contact with the electrode. The distal section also includes a plurality of optical elements configured to transmit one or more beams of exposure radiation away from the distal section of the catheter. The proximal section includes an optical source configured to generate a source beam of radiation and a detector configured to generate depth-resolved optical data. The multiplexer is configured to generate the one or more beams of exposure radiation from the source beam of radiation.