Observation of visible photons during infrared irradiation of bovine liver in the non-ablative regime

摘要

The biological-tissue response to laser irradiation has been a subject of intense research recently, because of the potential applications to non-invasive disease diagnosis. In this work, bovine liver was irradiated with 1060 nm laser light, both in the ablative and non-ablative regime. The light emitted by the tissue was detected in the visible spectra. The ablative regime was characterized by the strong signal generated due to photo-induced disruption of the biological tissue, resulting in strongly luminescent plasma. Under the non ablative regime, it was possible to detect visible light, which may be attributed to non-linear, multi-photon absorption, upconversion or other cooperative optical effect in the tissue molecules. The optical processes involved are discussed.