Side‐viewing handheld confocal Raman probe coupled with an off‐axis parabolic mirror for superficial epithelial Raman measurements of luminal organs

Abstract

Abstract We report on the development of a side‐viewing handheld confocal Raman probe coupled with an off‐axis parabolic (OAP) mirror for superficial epithelial Raman measurements of luminal organs. The OAP mirror realizes an effective numerical aperture of 0.36, a measured Raman excitation spot diameter of 130 μm and a depth of focus of 128 μm, allowing real time Raman spectra acquisition. The OAP mirror tilts the Raman optical path by 90°, making it well suited for superficial epithelium Raman interrogation of luminal organs. In addition, the probe results in no Raman interferences that may arise from transmission optics. The superficial epithelium Raman interrogation capability of the probe developed is validated through a two‐layer tissue phantom experiment. This work suggests the potential of the side‐viewing handheld confocal Raman probe coupled with an OAP mirror for enhancing the diagnosis of epithelial precancer and cancer of luminal organs.

Keywords

• handheld probe
• off‐axis parabolic mirror
• Raman spectroscopy
• side‐viewing