Fig. 1. Energy level diagram of Nd^{3+ [14]}

Fig. 2. Common strategies for Nd³⁺ 900 nm solid state lasers^[20]

Fig. 3. Frequency doubling blue laser of Nd∶YAG 900 nm laser pumped by laser diode array. (a) Experimental setup; (b) curves of output power and pump power ^[22]

Fig. 4. Spectral characteristic of the Nd∶YAG crystal. (a) Absorption spectra; (b) ⁴F_3/2→⁴I_9/2 transition fluorescence spectra; (c) ⁴F_3/2→⁴I_11/2 transition fluorescence spectra^[25]

Fig. 5. 10 W grade blue laser produced by Nd∶YVO₄ 900 nm laser frequency doubling^[31]

Fig. 6. Nd∶YAG ceramic 900 nm Q-switched laser based on Cr∶YAG saturable absorber^[38]

Fig. 7. Measured refractive index profile for W-type fiber^[42]

Fig. 8. Picosecond pulsed blue light laser based on W type Nd-doped silica fiber ^[46]

Fig. 9. Close to ten watt blue laser based on large-mode-area Nd-doped silica fiber^[48]

Fig. 10. Large mode field photonic crystal fibers for Nd³⁺ 900 nm laser. (a) 225 µm diameter^[49]; (b) 125 µm diameter^[50]

Fig. 11. Fluorescence imaging of zebrafish blood vessels by Nd³⁺ 900 nm femtosecond fiber laser^[53]

Fig. 12. Experimental setup of Nd³⁺ 900 nm all-fiber laser^[56]

Fig. 13. Al-Nd co-doped and I-Al-Nd co-doped silica glass. (a) Normalized fluorescence spectrum; (b) fluorescence decay spectrum^[66]

Fig. 14. MOPA amplifier based on I-Al-Nd co-doped silica fiber. (a) Optical path diagram; (b) input-output curve; (c) laser spectrum (inset: micrograph of the I-Al-Nd co-doped silica fiber cross section)