Fig. 1. Selected work achievements of III-V group inorganic nanosheet lasers. (a) Schematic diagram of CdSe/CdS@Cd_1-xZn_xS NPLs^[25]; (b) PL spectra of CdSe/CdS@Cd_1-xZn_xS NPL vertical cavity surface emitting laser^[25]; (c) cross-section schematic diagram of NPLs coated on optical fiber^[26]; (d) emission spectra of NPLs fiber under single-photon absorption excitation^[26]; (e) schematic diagram of NPLs-WGM microspheres^[27]; (f) emission spectra of microsphere laser, with inset showing corresponding microlaser at specific excitation power under microscope^[27]; (g) schematic diagram of copper-doped CdSe vertical cavity surface emitting laser^[28]; (h) relationship between luminescence intensity and full width at half maximum (FWHM) of copper-doped CdSe laser and pumping intensity^[28]

Fig. 2. Schematic diagram of metal halide perovskite nanosheets with different thicknesses^[29]

Fig. 3. Selected work achievements of perovskite nanosheet lasers. (a) PL spectra of (NMA)₂(FA)Pb₂Br₁I₆ thin film^[32]; (b) PL spectra of 2D R-P perovskite films (NMA)₂(FA)Pb₂Br_yI_7-y (y=7, 4, 3, 2, 1 and 0)^[32]; (c) optical image of top surface of (BA)₂PbI₄ (n=1) crystal^[33]; (d) graph of luminescence intensity versus pumping intensity for single crystals of (BA)₂(FA)_n-1Pb_nBr_3n+1, with inset showing the laser peak line width^[33]; (e) PL spectra of exfoliated (BA)₂(MA)_n-1Pb_nI_3n+1 single crystal at 77 K^[34]; (f) laser threshold of single crystal of (BA)₂(MA)_n-1Pb_nI_3n+1 with different n at optimal temperature^[34]; (g) R-P quasi-2D perovskite structure with organic amine monovalent amine ligand and D-J quasi-2D perovskite structure with octadecylamine divalent amine ligand^[36]; (h) changes in integrated ASE intensity after thermal treatment (130 ℃, 24 h) in air with different humidity levels^[36]; (i) schematic diagram of actual interface between perovskite gain layer and top DBR^[37]; (j) luminous intensity and FWHM as functions of pumping intensity^[37]; (k) PL spectra of NMA benchmar 2D perovskite laser^[38]; (l) graph of PL intensity and FWHM values as function of pulsed pumping flux^[38]

Fig. 4. Selected work achievements of III-V group inorganic nanowire lasers. (a) Transmission electron microscope image of single ZnS nanowire^[43]; (b) room temperature PL spectra of ZnS nanowire excited by laser with different power densities^[43]; (c) SEM image of bicyclic CdSe nanowire^[44]; (d) bicyclic CdSe nanowire laser spectrum^[44]; (e) relationship between luminous power and pump fluence for CdSe nanowires with no rings, single rings, and double rings^[44]; (f) SEM image of mixed MZI structure^[45]; (g) laser spectra of MZI structure laser at different pumping intensities^[45]; (h) relationship between laser output and pump intensity of excited CdS nanowires in coupled and uncoupled cases^[45]; (i) SEM image of multicolor plasma laser^[46]; (j) spectra of 5 plasma lasers^[46]; (k) schematic diagram of hybrid photon-plasma nanowire laser and coupling region^[47]; (l) laser spectra of Ag and CdSe end faces^[47]

Fig. 5. Selected work achievements of perovskite nanowire lasers. (a) SEM image of (BA)₂(FA)_n-1Pb_nBr_3n+1 R-P perovskite NWs array^[55]; (b) PL spectra of CsPbBr₃ NWs under different laser pumping fluxes with inset showing photo of CsPbBr₃ NWs in operation and graph of luminescence intensity versus pump intensity^[55]; (c) schematic diagram of CsPbBr₃ NWs laser^[56]; (d) log-log diagram of luminescence intensity versus pump fluence for CsPbX₃ NWs laser^[56]; (e) SEM image of hierarchical composition CsPbBr_xI_3-xNWs^[57]; (f) µ-PL spectra of CsPbBr_xI_3-x NWs at different locations above threshold^[57]; (g) graph of laser peaks at 521 nm and 556 nm versus pump fluence^[57]; (h) schematic diagram of NW laser pumped by 355 nm pump laser^[59]; (i) room temperature PL spectra of CsPbBr₃ NWs excited by 355 nm pulsed laser, with inset showing optical image of CsPbBr₃ NWs^[59]; (j) color images and PL spectra of CsPbBr_3xI_3-3x NWs with different components^[59]

Fig. 6. Optical gain process of double excitons in quantum dots

Fig. 7. Selected work achievements of III-V group inorganic QD lasers. (a) Schematic diagram of CdSe/CdS core/shell QD microdisk laser^[65]; (b) PL spectra of microdisk with diameter of 7 µm under different pumps, with inset shhowing PL image of microdisk recorded by camera^[65]; (c) PL intensity of microdisk laser as function of pump flux^[65]; (d) schematic diagram of preparation process of CdSe/CdS core-shell QD DFB laser^[66]; (e) spectra of DFB lasers with different grating periods^[66]; (f) luminescence spectra of microdisk lasers under different pumps^[67]

Fig. 8. Selected work achievements of perovskite QD lasers. (a) Relationship between luminescence intensity and pump fluence of CsPbBr₃ NC thin film^[68]; (b) ASE spectra of NC thin films with different components^[68]; (c) PL spectra of CsPbBr₃ NCs coated microsphere lasers^[68]; (d) PL spectra of CsPbBr₃ NCs thin films^[68]; (e) schematic diagram of configuration of CsPbBr₃ NCs vertical cavity surface emitting laser^[70]; (f) multimode laser spectra of CsPbBr₃ NCs vertical cavity surface emitting laser, with inset showing relationship between luminous intensity and pumping intensity^[70]; (g) schematic diagram of CsPbBr₃ QD vertical cavity surface emitting laser, with inset showing photo of device in operation^[71]; (h) graph of luminescence intensity versus pump intensity for CsPbBr₃ QD vertical cavity surface emitting laser^[71]; (i) stability characteristics of device under femtosecond and nanosecond pulses^[71]; (j) fabrication schematic diagram of CsPbBr₃ QD plasma lattice laser^[72]; (k) atomic force microscope image of CsPbBr₃ QD thin films^[72]; (l) luminescence spectra of CsPbBr₃ QD plasma lattice laser^[72]; (m) schematic diagram of thin-film ASE device^[73]; (n) PL spectra of PNC-CLC laser at different excitation powers^[73]; (o) relationship between PL intensity and FWHM and pump intensity of PCC-CLC laser^[73]; (p) schematic diagram of CsPbBr₃ NC vertical cavity surface emitting laser^[74]; (q) emission spectra at different pump intensities^[74]; (r) relationship between luminous intensity and FWHM with pump intensity^[74]; (s) laser spectrum at pump intensity of 1.1E_th^[74]

Fig. 9. Selected research achievements of electrically pumped devices. (a) Schematic diagram of laser diode structure based on DFB^[78]; (b) luminescence spectra of device at different pump densities^[78]; (c) optical pump excitation spectrum of device as function of pump flux after modifying functional layer^[79]; (d) electroluminescence spectra^[79]; (e) optical pumping input-output characteristics of top and bottom emitting devices ^[80]; (f) schematic representation of LED embedded in DBR microcavity and electroluminescence spectra of fabricated devices with and without DBR cavity for blue, green, and red light^[81]; (g) curves of current density and electroluminescent emission intensity versus voltage for CsSnBr₃ LED, with inset showing electroluminescence spectra^[82]; (h) EQE as function of current density for perovskite LED in pulse mode^[83]