Accurate optical information transmission through thick tissues using zero-frequency modulation and single-pixel detection

Delivering accurate information through thick biological tissues is critical in many biomedical applications. However, it is challenging to realize accurate optical information transmission and achieve large penetration depth due to complex structures and compositions of thick biological tissues. The absorption and scattering through biotissues are inter-related, and could cause light attenuation dramatically. In this paper, a new method based on zero-frequency modulation (ZFM) is proposed to generate a series of 2D random amplitude-only patterns for accurate optical information transmission through thick tissues at low light intensities. Light source modulated by the generated 2D patterns propagates through biological tissues, and a single-pixel bucket detector is used to record light intensity with a differential detection technique. Different sample thicknesses and the light source with different wavelengths are used to experimentally verify the proposed method. The proposed method can realize accurate optical information transmission through biological tissues with a thickness of 16.0 mm, when a low laser power of only 0.08 mW/cm² is used to illuminate the sample at wavelength of 658.0 nm. The proposed method realizes accurate optical information transmission through thick biological tissues, and is able to overcome the challenges, e.g., penetration through small-thickness tissues and low quality of the retrieved signals. The proposed method provides a promising means for optical data transmission through deep tissues.