Assessment of colloidal NaGdF4:Er3+/Yb3+ upconversion phosphor as contrast enhancer for optical coherence tomography

In-vitro imaging by swept-source optical coherence tomography (OCT) represents a class of advanced tomography that provides comprehensive and accurate clinical diagnostics. Here colloidal NaGdF4:Er3+/Yb3+ particles having an average size of 32 nm were successfully synthesized by a facial thermal decomposition method and then used as a contrast agent in OCT imaging. Prepared phosphor has shown bright green upconversion emission under 976 nm diode laser. The phosphor particles had increased the scattering of OCT scanning radiation, and thus higher image contrast was observed. The results indicate that upconversion phosphors may work as suitable contrast agents for OCT imaging.