A device, system, and method for identifying an area of ablated tissue and/or assessing contact between a treatment element and tissue and/or assessing occlusion of a body lumen by the treatment element. Specifically, the device, system, and method may include a device having one or more fiber sensors and a processing unit for receiving emitted and/or reflected light from tissue and making one or more determinations based on the received light regarding ablated tissue, tissue contact, and/or occlusion. Each of the fiber sensors may include at least one multimode waveguide segment and at least one singlemode waveguide segment, or each of the fiber sensors may be singlemode waveguide including fiber Bragg grating for assessing strain of a treatment element by tissue contact. The processing unit may include a beam processing apparatus and a hyperspectral imaging and analysis apparatus, and may optionally include a light source.
