Simultaneous visualization of multiple wavelengths by filter-free wavelength imaging system

This paper demonstrates the simultaneous imaging of multiple wavelengths through realizing a filter-free wavelength image sensor and imaging system. The sensor can identify the center wavelength of the spectrum based on the current ratio using the optical absorption characteristics of silicon at different wavelengths and the potential peak formed at depth. A wavelength imaging system was fabricated and calibrated by evaluating the light intensity and wavelength characteristics of each pixel. First, an experiment was conducted assuming that fluorescence was emitted in part of the pixel region of the image sensor. The system successfully identified different fluorescence wavelengths only in the region irradiated by light corresponding to the fluorescence using the current ratio. Finally, experiments were conducted using fluorescent beads on actual cells and pathogen clusters. Red and green fluorescent beads were placed separately on the sensor, and we succeeded in simultaneously imaging the wavelengths of the three regions where only the excitation light and different fluorescence signals were emitted. These results suggest that multiplexed fluorescence imaging, which considers the interactions between sites or targets, can provide new insights into the biomedical [Display omitted] •Identified wavelength by centroid of spectrum for multiple fluorescences.•Calibration of the realized wavelength-imaging system for intensity and wavelength.•Demonstration of wavelength imaging of the excitation light and fluorescence.•Simultaneous imaging of wavelength differences for two types of fluorescent beads.