Laser Wavelength & Material Absorption Chart
Understand why certain lasers work better for specific materials. This scientific reference shows absorption rates across different wavelengths, helping you choose the optimal laser type.
🔬 Why Wavelength Matters
When laser light hits a material surface, some energy is absorbed (converted to heat for cutting/melting), while the rest is reflected. The absorption rate depends heavily on the laser wavelength and material properties.
Metals
Metals reflect long wavelengths (CO2) but absorb short wavelengths (fiber, green, UV) well. Copper and aluminum are especially challenging due to high reflectivity.
Non-Metals
Organic materials (wood, acrylic, leather) absorb CO2 wavelength excellently. They're nearly transparent to fiber laser wavelengths.
Selection Rule
Higher absorption = more efficient cutting = lower power required. Always choose a laser with high absorption for your primary material.
Material Absorption Matrix
| Material | CO2 Laser 10600nm | Fiber Laser 1064nm | Nd:YAG Laser 1064nm | Green Laser (Frequency Doubled) 532nm | Blue Laser 450nm | UV Laser 355nm |
|---|---|---|---|---|---|---|
Mild Steel (Carbon Steel) Most common structural metal, excellent laser absorption in near-IR | 10% PoorRequires high power | 92% Excellent | 92% Excellent | 65% Good | N/A | 75% Very Good |
Stainless Steel (304/316) Corrosion-resistant alloy, similar absorption to mild steel | 8% Poor | 88% Excellent | 88% Excellent | 60% Good | N/A | 72% Very Good |
Aluminum (5000/6000 Series) Highly reflective, challenging for infrared lasers | 3% Very PoorVery high reflectivity | 25% FairRequires high power | 25% FairRequires high power | 55% Good | 62% Good | 75% Very Good |
Copper Extremely reflective, requires short wavelengths or very high power | 2% Very PoorNearly impossible | 18% PoorRequires 10kW+ | 18% PoorRequires 10kW+ | 50% Good | 65% Good | 70% Very Good |
Brass (CuZn) Copper-zinc alloy, slightly better absorption than pure copper | 5% Very Poor | 28% FairPossible with 6kW+ | 28% FairPossible with 6kW+ | 52% Good | 60% Good | 68% Very Good |
Titanium Excellent laser absorption, but requires inert atmosphere | 12% Poor | 90% ExcellentUse argon gas | 90% ExcellentUse argon gas | 68% Very Good | N/A | 78% Very Good |
Acrylic (PMMA) Ideal material for CO2 lasers, excellent absorption and edge quality | 95% ExcellentPolished flame-cut edges | 5% Very PoorMaterial damage | 5% Very PoorMaterial damage | 8% Very Poor | N/A | 35% FairFor marking only |
Polycarbonate (PC) Clear plastic with good CO2 absorption, but prone to yellowing | 88% GoodMay discolor | 8% Very Poor | 8% Very Poor | 12% Poor | N/A | 42% FairMarking/engraving |
Wood (Hardwood/Softwood) Natural material with excellent CO2 absorption | 90% Excellent | 12% PoorCharring | 12% PoorCharring | 18% Poor | N/A | 38% FairEngraving only |
Leather Organic material, ideal for CO2 laser engraving and cutting | 92% Excellent | 10% Very Poor | 10% Very Poor | 15% Poor | N/A | 35% Fair |
Silicon (Si) Semiconductor material, wavelength-dependent absorption | 55% Good | 65% Good | 65% Good | 75% Very Good | N/A | 85% ExcellentPrecision processing |
Glass (Soda-lime) Transparent material with selective absorption | 75% GoodHeat cracking risk | 5% Very PoorTransparent | 5% Very PoorTransparent | 8% Very Poor | N/A | 45% FairEngraving possible |
Mild Steel (Carbon Steel)
Most common structural metal, excellent laser absorption in near-IR
Stainless Steel (304/316)
Corrosion-resistant alloy, similar absorption to mild steel
Aluminum (5000/6000 Series)
Highly reflective, challenging for infrared lasers
Copper
Extremely reflective, requires short wavelengths or very high power
Brass (CuZn)
Copper-zinc alloy, slightly better absorption than pure copper
Titanium
Excellent laser absorption, but requires inert atmosphere
Acrylic (PMMA)
Ideal material for CO2 lasers, excellent absorption and edge quality
Polycarbonate (PC)
Clear plastic with good CO2 absorption, but prone to yellowing
Wood (Hardwood/Softwood)
Natural material with excellent CO2 absorption
Leather
Organic material, ideal for CO2 laser engraving and cutting
Silicon (Si)
Semiconductor material, wavelength-dependent absorption
Glass (Soda-lime)
Transparent material with selective absorption
Absorption Rate Legend
Laser Wavelength Reference
CO2 Laser
10600nmFiber Laser
1064nmNd:YAG Laser
1064nmGreen Laser (Frequency Doubled)
532nmBlue Laser
450nmUV Laser
355nm💡 Practical Selection Tips
For Steel & Stainless Steel
Choose fiber laser (1064nm) - 88-92% absorption rate provides excellent efficiency. CO2 lasers have only 8-10% absorption, requiring much higher power.
For Aluminum & Copper
Highly reflective materials. Use high-power fiber (6kW+), or better yet, green laser (532nm) or blue laser (450nm) with 55-65% absorption rates.
For Acrylic, Wood & Plastics
CO2 laser (10600nm) is the clear winner with 90-95% absorption. Produces polished edges on acrylic. Fiber lasers don't work well on these materials.
For Precision Electronics
UV laser (355nm) provides excellent absorption across most materials with minimal heat affected zone. Ideal for PCBs, silicon, and micro-machining.
Real-World Application Examples
Case Study 1: Sheet Metal Fabrication Shop (Steel/Stainless)
Challenge: Shop processes 70% mild steel (1-6mm), 25% stainless steel (1-4mm), 5% aluminum (1-3mm). Considering CO2 vs Fiber laser investment.
Wavelength Analysis: Mild steel absorbs 88% of 1064nm (fiber) vs 8% of 10600nm (CO2). Stainless steel: 92% (fiber) vs 10% (CO2). Aluminum: 8% (fiber) vs 2% (CO2).
Decision: 6kW fiber laser selected. For steel/stainless (95% of volume), fiber provides 9-10x better absorption than CO2, enabling 3x faster cutting speeds and 60% lower operating costs. Aluminum remains challenging but manageable with proper parameters. Alternative considered: 12kW CO2 would cost 40% more initially and $20,000/year more in operating costs while providing inferior performance on primary materials.
Result: Fiber laser cuts 3mm mild steel at 12 m/min vs 4 m/min with equivalent CO2 power. Payback period: 2.1 years vs 3.8 years for CO2 option.
Case Study 2: Signage & Display Manufacturer (Acrylic/Wood)
Challenge: Company produces custom signage from acrylic (60%), wood (30%), and occasional thin metals (10%). Evaluating laser options for clean edge quality and versatility.
Wavelength Analysis: Acrylic absorbs 95% of 10600nm (CO2) but only 5-10% of 1064nm (fiber). Wood: 92% (CO2) vs 15% (fiber). Thin metals favor fiber but represent minority of work.
Decision: 150W CO2 laser chosen. Acrylic cutting with CO2 produces flame-polished edges (no post-processing needed) due to excellent absorption and longer wavelength's thermal characteristics. Fiber laser would require 3-5x more power for equivalent results and would produce frosted edges requiring flame polishing. For occasional thin metal work, outsource or use mechanical cutting.
Result: 10mm acrylic cuts at 15 mm/s with mirror-finish edges. Total system cost $45,000 vs $120,000+ for fiber laser with insufficient non-metal capability. Edge quality eliminates $15,000/year in polishing labor.
Case Study 3: Electronics Manufacturer (Aluminum Housings & PCBs)
Challenge: Cutting thin aluminum enclosures (0.5-2mm) and precision PCB features. Standard fiber lasers struggle with aluminum's 92% reflectivity at 1064nm wavelength.
Wavelength Analysis: Aluminum absorption: 8% at 1064nm (fiber), 12% at 10600nm (CO2), 55% at 532nm (green), 65% at 450nm (blue). For precision work, shorter wavelengths also provide smaller spot sizes and reduced heat-affected zones.
Decision: Dual-wavelength solution: 500W green laser (532nm) for aluminum cutting, 50W UV laser (355nm) for PCB micro-machining. Green laser's 7x better aluminum absorption vs fiber enables clean cutting at lower power with minimal dross. UV laser's 355nm wavelength provides <10μm spot size for precision PCB features (via drilling, trace cutting) with negligible thermal damage to surrounding components.
Result: Aluminum cutting speed increased 4x vs previous fiber laser attempts. PCB processing achieves ±5μm accuracy with zero charring. Combined system cost $180,000 vs $250,000 for high-power fiber (12kW+) that would still struggle with aluminum and lack PCB precision capability.
Case Study 4: Automotive Tier 1 Supplier (Mixed Materials & High Volume)
Challenge: High-volume production of structural components (steel), decorative trim (stainless), and battery enclosures (aluminum). Need maximum throughput and flexibility across material types.
Wavelength Analysis: Steel/stainless: 88-92% absorption at 1064nm (excellent). Aluminum: 8% at 1064nm (challenging but manageable with high power). Volume breakdown: 60% steel, 30% stainless, 10% aluminum.
Decision: Dual 12kW fiber laser system. High power compensates for aluminum's poor absorption (12kW × 8% = effective 960W absorbed, sufficient for 3mm aluminum at production speeds). For steel/stainless (90% of volume), 12kW provides extreme speeds: 3mm steel at 25 m/min, 6mm steel at 8 m/min. Dual systems provide redundancy for 24/7 operation.
Result: System processes 180 tons/month vs 120 tons with previous 6kW systems. Aluminum cutting improved from "problematic" to "acceptable" with optimized parameters (high nitrogen pressure 18 bar, dynamic power modulation). Total investment $800,000 for dual 12kW systems vs $1.2M for specialized green laser solution. ROI: 18 months based on throughput gains.
Technical Deep Dive: Absorption Physics
Why Metals Reflect Long Wavelengths
Metals contain free electrons that respond to electromagnetic radiation. At long wavelengths (CO2's 10.6μm), these electrons oscillate efficiently and re-radiate the energy as reflection. At shorter wavelengths (fiber's 1.06μm), electron response time cannot match the rapid oscillations, causing energy absorption instead of reflection. This is why fiber lasers (1064nm) achieve 88-92% absorption on steel while CO2 lasers (10600nm) achieve only 8-10%.
Temperature Dependence of Absorption
Absorption rates increase with temperature. Cold aluminum at room temperature absorbs ~8% of 1064nm radiation, but once heated to 400-600°C during cutting, absorption increases to 15-25%. This is why aluminum cutting requires high-power fiber lasers—initial breakthrough is difficult (low absorption), but once material heats up, cutting becomes more efficient. This also explains why piercing aluminum is more challenging than continuous cutting.
Surface Finish Impact
Polished metal surfaces reflect more than oxidized or rough surfaces. Mill scale (oxide layer) on hot-rolled steel absorbs 30-40% more laser energy than clean cold-rolled steel. This is why cutting rusty or oxidized materials is often easier than cutting pristine material. Some fabricators intentionally use light surface oxidation (via chemical treatment or controlled rust) to improve fiber laser absorption on aluminum and copper.
Wavelength Selection Strategy
Primary Material Rule: Choose wavelength optimized for your highest-volume material (typically 70%+ of work). Accept compromises on secondary materials or outsource them. A fiber laser optimized for steel will struggle with aluminum, but if aluminum is only 10% of volume, this is acceptable. Conversely, trying to cut steel with a CO2 laser (optimized for non-metals) results in 10x slower speeds and uneconomical operation.
Multi-Material Shops: If no single material dominates (e.g., 40% steel, 40% aluminum, 20% acrylic), consider dual-laser solution or hybrid systems. Total cost of two specialized lasers (fiber + CO2) is often lower than attempting one "compromise" solution that performs poorly on all materials. Calculate based on throughput requirements and material-specific absorption rates.
🔧 Related Resources
Data Disclaimer: This wavelength absorption data is based on published scientific literature and laser physics principles, for reference only. Actual absorption rates vary with surface condition, temperature, material purity, and specific alloy composition. Always conduct material tests before production. Data last updated: 2025-10-30.