Deep-penetration medical spectroscopy imaging method utilizing multibeam interference

Abstract

Medical spectral imaging can not only show the geometric shapes of biological tissues, but also reveal their chemical and physical characteristics, making it a powerful tool for medical diagnosis. Although existing multispectral and hyperspectral imaging techniques can provide detailed biochemical and biophysical data, their penetration depth in the human body is severely limited by the strong optical absorption and scattering of biological tissues. In this theoretical study, we propose a spectral imaging method with a deep penetration depth. It combines multi-beam interference, engineered dispersion, time-gated detection, and wavelength-selective imaging. The method first uses a negative-dispersion device to broaden a short laser pulse, and then uses the positive dispersion of biological tissues themselves to recompress the broadened pulse. In this way, the optical field energy is redistributed along the pulse propagation path: the light intensity remains low enough to avoid damage to biological tissue during propagation, while the number of coherent ballistic photons at a specific imaging depth is increased, enabling depth-selective targeted illumination. On the return path of the signal laser pulse, a tunable wavelength filter is used to sequentially and selectively transmit wavelength-resolved image slices, thereby constructing a spectral data cube for medical diagnosis or disease analysis. This method aims to integrate deep penetration, high resolution, tomographic capability, and spectral discrimination within a single imaging system. Calculations show that, under ideal conditions, the maximum imaging depth inside the human body can approach 100 millimeters, with a lateral imaging resolution of approximately 1 micrometer. Its spectral resolution is approximately 1 nanometer in the visible to near-infrared range.