Highly sensitive characterization of surface plasmon resonance (SPR) modes lays the solid foundation for wide SPR-related applications. Herein. we discover that these SPR modes based on all-metal nanostructures without any probed molecule can be characterized with ultrahigh sensitivities at both excitation and emission wavelengths by utilizing plasmon-enhanced sum frequency generation... https://medicalwarehouses.shop/product-category/enteral-feeding/