Fig. 6 | Nature Communications

Fig. 6

From: Low irradiance multiphoton imaging with alloyed lanthanide nanocrystals

Fig. 6

Deep-tissue imaging of aUCNPs at low excitation intensity. Imaging of 12-nm core/shell NaEr0.6Yb0.4F4 (8-nm core wth 2-nm shell) aUCNPs injected into mammary fat pads 3–4 mm below the skin at a 2 h, b 4 h, and c 6 h after injection. Laser intensity is 0.1 W cm−2 focused at or near the injection site, and emission is from the Er3+ 4S3/2 band (530–550 nm). SBR: signal-to-background ratio