Fig. 1. Schematic of refractive index profile of semiconductor nanowire

Fig. 2. Mode characteristics of semiconductor nanowires. Scale bar: 50 nm. (a) Electric fields of HE₁₁, TE₀₁, and TM₀₁ modes in freestanding ZnO nanowire with a radius of 80 nm at 380 nm in the equivalent of a circular waveguide; (b) propagation constant of the mode in the ZnO nanowire varies with the diameter of the ZnO nanowire at 380 nm. ω is the angular frequency, R is the radius of the nanowire, and c is the speed of light in vacuum; (c) electri

Fig. 3. Schematics of output mode characteristics of semiconductor nanowire lasers with different cavity lengths. (a) Schematic of laser output mode characteristics with a long cavity. Inset shows the corresponding cavity structure; (b) schematic of laser output mode characteristics with a short cavity. Inset shows the corresponding cavity structure

Fig. 4. Single-mode nanobelt lasers and their output characteristics^[63]. (a) SEM image of CdSe nanobelts with obvious bumps; (b) optical microscope image of nanobelt lateral emission laser; (c) lateral laser spectrum of nanobelt laser; (d) laser emission intensity and line width as functions of pump power

Fig. 5. Evanescent-wave pumped nanowire laser with core-shell nano structure and its output characteristics^[51]. (a) Schematic of core-shell structure (left) and its SEM image; (b) emission spectra of the nanowire. Inset shows the CCD images of the nanowire laser and its laser pattern; (c) pump energy dependent intensity and linewidth

Fig. 6. Structure and spectral characteristics of InGaA/InGaP one-dimensional nanowire array lasers^[70-71]. (a) 1100 nm band one-dimensional nanowire array laser structure and its output spectra. Inset shows L-L curve of the laser peak^[70]; (b) structure of one-dimensional nanowire array laser at telecom-wavelengths and its output spectra^[

Fig. 7. Schematic of Vernier effect of coupled cavities and typical coupled cavities. (a) Schematic of Vernier effect; (b) coupled cavity with loop mirror; (c) X-shape cavity; (d) cleaved-coupled cavity

Fig. 8. Nanowire lasers with loop mirror coupling cavity and their output characteristics^[26]. (a) SEM image and corresponding output spectra of laser without loop mirror, with single loop mirror, and with double loops; (b) L-L curves of laser peaks of three lasers

Fig. 9. Cleaved-coupled nanowire laser and its spectral characteristics^[24]. (a) SEM image of cleaved-coupled nanowire laser; (b) laser spectrum of coupled cavity and single separated nanowire subcavity

Fig. 10. Schematic of FP-WGM coupled cavity nanowire laser and its spectral characteristics^[83]. (a) Schematic of FP-WGM coupled cavity nanowire laser; (b) reversible tuning characteristics of laser and corresponding spectra

Fig. 11. DFB nanowire lasers^[67]. (a) Schematic of the DFB nanowire lasers, in which the nanowires have three different angular orientations; (b) SEM image of a single nanowire placed on DFB substrate; (c) laser spectrum of nanowires with different angle orientations

Fig. 12. Laser spectrum of the same semiconductor nanowire laser with different pump positions. Inset shows the CCD image of corresponding nanowire laser^[68]