Chromatic aberration free reflective mirror-based optical system design for multispectral photoacoustic instruments

BACKGROUND: Current multispectral photoacoustic instruments must use large and separate combinational structures to obtain various biological tissue information for multispectral ranges. OBJECTIVE: The optical aberration generated from the multispectral photoacoustic systems may reduce the image quality of biological tissue because the improper structures for combining light of different wavelength cannot produce good optical ray convergence points. To prevent this, complex combined structures need to be considered at the design level for multispectral photoacoustic systems. METHODS: In place of an optical refracted lens system, reflective mirrors could be designed for optical systems. To verify our proposed idea, we assessed optical distortion performance using red, green, and blue light, and combined optical light sources to compare their chromatic aberration characteristics. RESULTS: The high optical performance is realized regardless of the wavelength for a light source combined with multiple wavelengths, because our optical system was designed with only a reflective surface. CONCLUSIONS: The designed optical system using a reflective mirror can provide multispectral optical sources (such as infrared, visible, and ultraviolet optical lights) with only one light ray path, without any chromatic aberrations.