Since 1960, when Maiman invented the laser, the laser family has continuously evolved and expanded. Today, it has developed into multiple branches. According to the type of gain medium, lasers can be divided into five mainstream categories: gas, solid-state, fiber, semiconductor, and dye, as well as special frontier categories such as chemical, free-electron, and X-ray lasers. The following sections provide detailed technical parameters, core characteristics, and typical applications for each type, covering the full spectrum from mW-level scientific research sources to hundred-kW-level industrial processing, and from deep ultraviolet to terahertz wavelengths.
1. Gas Lasers (First to be commercialized, market share approximately 6.8%)
These generate laser light through energy level transitions of gas molecules, atoms, or ions. They are characterized by extremely wide wavelength coverage, excellent beam quality, and good coherence. However, they generally suffer from large size, low efficiency, and complex maintenance. They are gradually being replaced by fiber and semiconductor lasers, but remain irreplaceable in specific wavelengths and applications.
1.1 Molecular Gas Lasers
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Carbon Dioxide (CO₂) Laser | 10.6 μm (main wavelength), 9.3 μm, 9.6 μm | Continuous output power up to 100 kW, extremely strong absorption by non-metal materials, electro-optical conversion efficiency of 10–15% | Non-metal cutting / welding / engraving, leather processing, packaging marking, medical aesthetics (freckle removal, wrinkle treatment), heat treatment |
| Carbon Monoxide (CO) Laser | 5–6 μm | Shorter wavelength, better metal absorption, efficiency 50% higher than CO₂ lasers | Thin metal cutting, precision welding, medical surgery |
| Nitrogen (N₂) Laser | 337.1 nm (UV) | Extremely short pulse width (ns level), high peak power, simple structure | Dye laser pumping source, fluorescence excitation, spectral analysis, laser radar |
| Hydrogen Fluoride (HF) / Deuterium Fluoride (DF) Chemical Laser | 2.6–3.0 μm (HF), 3.5–4.0 μm (DF) | Extremely high power (up to MW level), no external power supply required | Defense industry (laser weapons), industrial processing |
2. Atomic Gas Lasers
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Helium-Neon (He-Ne) Laser | 632.8 nm (red), 543.5 nm (green), 1.15 μm (infrared) | Excellent beam quality (M² ≈ 1.0), long coherence length, long lifetime (up to 100,000 hours) | Laser alignment, optical measurement, educational demonstrations, barcode scanning, holography |
| Helium-Cadmium (He-Cd) Laser | 325 nm (UV), 441.6 nm (blue) | Single-mode output, narrow linewidth, high ultraviolet power | Laser plate making, fluorescence excitation, spectral analysis, biomedical imaging |
| Copper Vapor Laser | 510.6 nm (green), 578.2 nm (yellow) | High peak power, high repetition rate (up to 100 kHz), high average power | Laser marking, dye laser pumping, isotope separation, laser displays |
| Gold Vapor Laser | 627.8 nm (red) | High red-light power, good beam quality | Laser medical treatment, laser displays |
3. Ion Gas Lasers
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Argon Ion (Ar⁺) Laser | 488 nm (blue), 514.5 nm (green) | Multi-wavelength output, high power (up to several tens of watts), excellent beam quality | Laser displays, ophthalmic surgery, confocal microscopy, holography, spectral analysis |
| Krypton Ion (Kr⁺) Laser | 647.1 nm (red), 568.2 nm (yellow), 413.1 nm (violet) | Capable of RGB three-color output, high power | Laser displays, laser medical treatment, scientific research |
| Mixed Gas Ion Laser | 457.9 nm – 676.4 nm (multi-wavelength) | Simultaneous output of multiple visible wavelengths | Laser displays, spectral analysis |
4. Excimer Lasers
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Argon Fluoride (ArF) Excimer Laser | 193 nm (deep ultraviolet) | Extremely high photon energy, cold processing characteristics, no thermal damage | Semiconductor lithography (DUV), LASIK excimer laser eye surgery, material surface modification |
| Krypton Fluoride (KrF) Excimer Laser | 248 nm (deep ultraviolet) | High power, high repetition rate | Semiconductor lithography, laser marking, micromachining |
| Xenon Chloride (XeCl) Excimer Laser | 308 nm (ultraviolet) | Moderate wavelength, good absorption by biological tissues | Dermatological treatments (psoriasis, vitiligo), laser marking, micromachining |
| Xenon Fluoride (XeF) Excimer Laser | 351 nm (near ultraviolet) | High power, excellent beam quality | Laser marking, micromachining, scientific research |
2. Solid-State Lasers (Traditional mainstream, market share approximately 15.7%)
These use crystals, glass, or ceramics doped with rare earth ions or transition metal ions as the gain medium. They are characterized by high power density, large pulse energy, and rich wavelength diversity. They represent the main technological path for high-power pulsed lasers and special wavelength lasers.
2.1 Crystal Lasers (The most mature type of solid-state lasers)
| Gain Medium | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) | 1064 nm (main wavelength), 946 nm, 1319 nm | Four-level system, low threshold, high gain, excellent thermal conductivity, most mature technology | Industrial cutting / welding / marking, laser ranging, ophthalmic surgery, laser guidance, pump source |
| Nd:YVO₄ (Neodymium-doped Yttrium Orthovanadate) | 1064 nm, 532 nm | Large stimulated emission cross-section, high efficiency, excellent beam quality, compact size | Laser marking, laser displays, biomedical imaging, pump source |
| Yb:YAG (Ytterbium-doped Yttrium Aluminum Garnet) | 1030 nm | Extremely low quantum defect (<9%), low thermal load, strong energy storage capability, suitable for high-concentration doping | 10,000-watt-class thin-disk lasers, ultrafast lasers, industrial processing, coherent synthesis |
| Tm:YAG (Thulium-doped Yttrium Aluminum Garnet) | 1940 nm, 2013 nm | Strong water absorption, minimal thermal damage, high ablation precision | Medical soft tissue ablation, urological surgery, plastic welding, infrared countermeasures |
| Ho:YAG (Holmium-doped Yttrium Aluminum Garnet) | 2100 nm | Excellent hard tissue ablation effect, moderate penetration depth | Urinary stone lithotripsy, orthopedic surgery, liver tumor ablation, defense industry |
| Er:YAG (Erbium-doped Yttrium Aluminum Garnet) | 2940 nm | Strongest water absorption (10,000× higher than 1064 nm), extremely low thermal damage | Dental cutting, aesthetic skin treatment, precise superficial tissue ablation, dermatology treatment |
| Ti:Sapphire (Titanium Sapphire) | 700–1100 nm (continuously tunable) | Extremely wide tuning range, broad gain bandwidth, capable of generating femtosecond pulses | Femtosecond ultrafast lasers, scientific research, nonlinear optics, quantum optics |
| Cr:LiSAF / Cr:LiCAF | 800–1000 nm (tunable) | Wide tuning range, directly diode-pumped, high efficiency | Femtosecond lasers, scientific research, laser radar |
| Nd:YLF | 1047 nm, 1053 nm | Naturally polarized, low thermal lensing effect, high pulse energy | Laser marking, laser ranging, pump source |
2. Glass Lasers
| Gain Medium | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Neodymium Glass Laser | 1053 nm | Can be manufactured in large sizes, high energy storage capability, extremely high pulse energy (up to MJ level) | Nuclear fusion research (inertial confinement fusion), laser weapons, scientific research |
| Erbium Glass Laser | 1540 nm | Eye-safe, compact size, lightweight | Laser ranging, laser radar, optical communication |
3. Ceramic Lasers
| Gain Medium | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Nd:YAG Ceramic | 1064 nm | High thermal conductivity, capable of high-concentration doping, low manufacturing cost, large size scalability | High-power lasers, industrial processing, defense industry |
| Yb:YAG Ceramic | 1030 nm | Low quantum defect, high thermal conductivity, strong energy storage capability | 10,000-watt-class thin-disk lasers, industrial processing |
| Tm:YAG Ceramic | 1940 nm | High thermal conductivity, suitable for high-concentration doping | High-power medical lasers, industrial processing |
4. Diode-Pumped Solid-State Lasers (DPSS)
Core Principle: Uses semiconductor lasers as the pump source, replacing traditional flash lamp pumping. This is currently the absolute mainstream technical route for solid-state lasers.
Technical Characteristics: High electro-optical conversion efficiency (can reach over 30%), long lifespan, compact size, good stability.
Typical Products: 532nm green lasers, 355nm ultraviolet lasers, 266nm deep ultraviolet lasers.
Main Applications: Laser marking, precision micromachining, laser displays, biomedical imaging.
3. Fiber Lasers (Absolute mainstream in the market, market share approximately 42.1%)
These use rare-earth-doped silica optical fiber as the gain medium. They offer the highest electro-optical conversion efficiency (can reach over 45%), good beam quality, long lifespan, maintenance-free operation, and compact size. They are currently the fastest-growing and most widely applied type of laser.
(I) Classification by Gain Medium (The most core classification)
| Gain Medium | Core Wavelength | Technical Features | Main Applications |
|---|---|---|---|
| Ytterbium (Yb³⁺) Fiber Laser | 1030–1080 nm (main wavelength 1064 nm) | Low quantum defect, high efficiency, high power, single-fiber output up to 150 kW | Industrial cutting / welding / marking, 3D printing, new energy processing, aerospace |
| Thulium (Tm³⁺) Fiber Laser | 1900–2100 nm (main wavelength 1940 nm) | Strong water absorption, minimal thermal damage, high ablation precision | Medical soft tissue ablation, urological surgery, plastic welding, infrared countermeasures |
| Erbium (Er³⁺) Fiber Laser | 1530–1565 nm (C-band), 1565–1625 nm (L-band) | Operates within low-loss optical communication windows, eye-safe | Optical fiber communication, fiber optic sensing, laser radar, ophthalmic surgery |
| Holmium (Ho³⁺) Fiber Laser | 2050–2150 nm (main wavelength 2100 nm) | Excellent hard tissue ablation effect, moderate penetration depth | Urinary stone lithotripsy, orthopedic surgery, defense industry |
| Praseodymium (Pr³⁺) Fiber Laser | 480 nm (blue), 523 nm (green), 630 nm (red) | Direct visible light output without frequency doubling | Photodynamic therapy (PDT), laser displays, biomedical imaging |
| Bismuth (Bi³⁺) Fiber Laser | 1100–1800 nm | Wide tuning range, covers O-E-S-C-L full communication bands | Optical fiber communication, broadband light sources, scientific research |
(II) Classification by Operating Mode
1. Continuous Wave (CW) Fiber Lasers: Power range 1W-150kW. Applications: industrial cutting/welding, medical ablation, surface treatment.
2. Pulsed Fiber Lasers:
- Q-Switched Nanosecond Pulse: 1-200ns pulse width, 1-100kW peak power. Applications: marking, engraving, drilling.
- MOPA Pulse: 1ns-1ms adjustable pulse width, 1kHz-10MHz repetition rate. Applications: precision micromachining, medical ablation.
- Mode-Locked Picosecond/Femtosecond Pulse: 10fs-1000ps pulse width, 1MW-10GW peak power. Applications: ultra-precision machining, ophthalmic surgery.
- Gain-Switched Pulse: 10-100ns pulse width, 1GHz repetition rate. Applications: fiber optic communication, LiDAR.
(III) Classification by Output Characteristics
1. Single-mode / Multimode Fiber Lasers: Single-mode M² < 1.5, multimode M² = 2-10.
2. Single-frequency / Narrow-linewidth Fiber Lasers: Single-frequency linewidth < 1MHz, narrow-linewidth 1MHz-10GHz.
3. Polarization-maintaining / Linearly Polarized Fiber Lasers: Extinction ratio > 20dB. Applications: nonlinear frequency conversion, coherent communication.
4. Supercontinuum Fiber Lasers: Spectral coverage 400nm-2500nm. Applications: OCT imaging, spectral analysis.
5. Nonlinear Fiber Lasers:
- Second-order nonlinearity: Frequency doubling, sum-frequency generation, difference-frequency generation, optical parametric oscillators (OPO).
- Third-order nonlinearity: Raman fiber lasers, Brillouin fiber lasers, four-wave mixing lasers.
6. Single-wavelength / Multi-wavelength Switchable Fiber Lasers: Wavelength-tunable or simultaneous multi-wavelength output.
(IV) Classification by Power Level (2026 Industrial Standards)
- Low Power: < 100W
- Medium Power: 100W – 1kW
- High Power: 1kW – 10kW
- Ultra-high Power: > 10kW
4. Semiconductor Lasers (Foundational core, market share approximately 33.2%)
These use semiconductor materials as the gain medium, generating laser light through electrical injection excitation. They are characterized by the smallest size, highest efficiency (can reach over 60%), longest lifespan, and lowest cost. They serve as the “heart” of all lasers (as pump sources) and are also the core light source in fields such as consumer electronics, optical communications, and LiDAR.
1. Edge-Emitting Lasers (EEL)
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Fabry–Pérot (FP) Laser | 650 nm, 780 nm, 850 nm, 980 nm, 1064 nm | Simple structure, low cost, high power | Laser pointers, laser printing, short-distance optical fiber communication, pump sources |
| Distributed Feedback (DFB) Laser | 1310 nm, 1550 nm, 976 nm, 793 nm | Narrow linewidth, excellent wavelength stability, single-mode output | Optical fiber communication, coherent laser radar, pump sources |
| Distributed Bragg Reflector (DBR) Laser | 1310 nm, 1550 nm | Tunable wavelength, narrow linewidth | Optical fiber communication, optical spectral analysis, laser radar |
| Quantum Well (QW) Laser | 650 nm – 1600 nm | High efficiency, low threshold current, high power | Pump sources, laser displays, optical communication |
| Quantum Dot (QD) Laser | 650 nm – 1600 nm | Wide gain bandwidth, excellent temperature stability, low threshold current | Optical communication, laser displays, pump sources |
2. Vertical-Cavity Surface-Emitting Lasers (VCSEL)
- Core Wavelengths: 850nm, 940nm, 1310nm, 1550nm
- Technical Characteristics: Good beam quality, small divergence angle, can be arrayed, low cost, long lifespan
- Main Applications: 3D sensing (facial recognition), LiDAR, data center optical interconnects, laser displays, laser mice
3. Specialty Semiconductor Lasers
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Quantum Cascade Laser (QCL) | 3–20 μm (mid-infrared) | Mid-infrared wavelength coverage, continuous-wave operation at room temperature, high power | Gas detection, environmental monitoring, defense & security, medical diagnostics |
| Interband Cascade Laser (ICL) | 3–6 μm (mid-infrared) | High efficiency, low threshold current, low power consumption | Portable gas detection, environmental monitoring |
| External Cavity Diode Laser (ECDL) | 600 nm – 1600 nm (tunable) | Narrow linewidth, wide wavelength tunability | Spectral analysis, optical fiber communication, scientific research |
| Semiconductor Optical Amplifier (SOA) | 1310 nm, 1550 nm | Wide gain bandwidth, compact size | Optical communication, optical signal processing |
5. Dye Lasers (Niche specialty, market share < 0.5%)
These use organic dye solutions as the gain medium. They are characterized by an extremely wide continuously tunable wavelength range, but suffer from poor stability, complex maintenance, and dye toxicity. They have been largely replaced by fiber lasers and semiconductor lasers, with only a few applications remaining in research and specialty fields.
- Core Wavelengths: 300nm-1000nm (continuously tunable)
- Technical Characteristics: Wide tuning range, large gain bandwidth, capable of generating ultrashort pulses
- Main Applications: Scientific research, spectral analysis, laser medicine, isotope separation, laser displays
6. Other Specialty Lasers
1. Chemical Lasers
- Core Principle: Generate laser light through energy released from chemical reactions, requiring no external power supply
- Typical Types: HF/DF chemical lasers, Chemical Oxygen-Iodine Lasers (COIL)
- Technical Characteristics: Extremely high power (can reach MW level), wavelength coverage in the infrared
- Main Applications: Defense and military (laser weapons), industrial processing
2. Free-Electron Lasers (FEL)
- Core Principle: Generate laser light through the interaction of a relativistic free-electron beam with a periodic magnetic field
- Core Wavelengths: Continuously tunable across the full spectrum from microwave to X-ray
- Technical Characteristics: Extremely wide wavelength tunability, high power, good beam quality
- Main Applications: Nuclear fusion research, materials science, biomedical imaging, defense and military
3. X-ray Lasers
- Core Wavelengths: 0.1-10nm (X-ray)
- Technical Characteristics: Short wavelength, high photon energy, extremely high resolution
- Main Applications: Materials science, biomedical imaging, semiconductor lithography, scientific research
4. Terahertz Lasers
- Core Wavelengths: 30μm-3mm (terahertz band)
- Technical Characteristics: Strong penetration, non-damaging to biological tissue, good spectral fingerprint characteristics
- Main Applications: Security screening, biomedical imaging, spectral analysis, communications
7. Global Laser Market Share Summary (2025 Data)
| Specific Type | Core Wavelength | Technical Features | Typical Applications |
|---|---|---|---|
| Quantum Cascade Laser (QCL) | 3–20 μm (mid-infrared) | Mid-infrared wavelength coverage, continuous-wave operation at room temperature, high power | Gas detection, environmental monitoring, defense & security, medical diagnostics |
| Interband Cascade Laser (ICL) | 3–6 μm (mid-infrared) | High efficiency, low threshold current, low power consumption | Portable gas detection, environmental monitoring |
| External Cavity Diode Laser (ECDL) | 600 nm – 1600 nm (tunable) | Narrow linewidth, wide wavelength tunability | Spectral analysis, optical fiber communication, scientific research |
| Semiconductor Optical Amplifier (SOA) | 1310 nm, 1550 nm | Wide gain bandwidth, compact size | Optical communication, optical signal processing |
