Physics / mechanism
Laser = Light Amplification by Stimulated Emission of Radiation. A gain medium (semiconductor, fiber, gas, crystal) is pumped to population inversion; photons stimulate coherent emission, with mirrors forming a resonant cavity. Key parameters: wavelength, linewidth, output power, wall-plug efficiency, coherence length, beam quality (M²). Semiconductor diode lasers dominate volume (850 nm VCSELs for datacom, 976 nm pump lasers, 1550 nm DFBs for coherent comms). Edge-emitters reach >10 W CW; VCSELs scale to 2D arrays. QCLs cover mid-IR (3–12 µm). State-of-art: co-packaged optics pushing silicon photonics integration with on-chip III-V lasers (heterogeneous bonding, wafer-scale); sub-kHz linewidth ECLs for coherent LiDAR.
Competitive landscape
Diode lasers compete with LEDs (incoherent, lower cost, sufficient for illumination/sensing below ~10 m), OLEDs (display), and broadband sources. Adjacent: optical amplifiers (EDFAs, SOAs), nonlinear frequency converters (OPOs, SHG), and ultrafast pulsed systems (mode-locked fiber lasers). Primary substitution risk is from integrated photonics moving laser function on-chip, commoditising discrete components.
| Type | Wavelength range | Key application |
|---|---|---|
| VCSEL | 850–1550 nm | Datacom, 3D sensing |
| DFB/ECL | 1270–1610 nm | Coherent telecom, LiDAR |
| QCL | 3–12 µm | Gas sensing, defence |
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.