Quick answer

The best coating for your laser mirror depends on your working wavelength: enhanced aluminum (450–2000 nm), protected silver (450–2000 nm and 2–10 µm), UV enhanced aluminum (250–450 nm), or uncoated substrates for custom coatings.

Why the coating matters more than the substrate

All Esco Optics flat mirrors share the same 1/10 wave surface accuracy and 40/20 scratch-dig quality, so the coating largely determines which wavelengths reflect efficiently. Choosing the wrong coating means losing power or signal, even with a perfect substrate.

Trade-off: reflectivity vs. durability

Protected silver offers the highest average reflectivity (Ravg > 97.5% from 450–2000 nm and > 97% from 2–10 µm) but can tarnish if the protective layer is scratched. Enhanced aluminum is slightly less reflective (Ravg > 90%) yet more robust for general lab use. UV enhanced aluminum trades visible reflectivity for deep UV performance.

Decision rules for choosing a coating

  • If your laser is in the UV (250–450 nm): Choose UV Enhanced Aluminum (Ravg > 90% in that band). Standard enhanced aluminum or silver will not reflect UV efficiently.
  • If your laser is visible or near-IR (450–2000 nm) and you need a balance of cost and performance: Choose Enhanced Aluminum. It covers the most common diode and solid-state laser lines with good reflectivity and is available on both Borofloat-33 and Fused Silica substrates.
  • If your laser is in the near-IR or mid-IR (450 nm–10 µm) and you need maximum reflectivity: Choose Protected Silver. It offers the highest average reflectivity across this broad range, but is only offered on Borofloat-33 substrates. If you need a Fused Silica substrate, Enhanced Aluminum is the next best option.
  • If you plan to apply your own custom coating: Start with an Uncoated flat mirror (Borofloat-33 substrate). This gives you a clean, 1/10 wave surface to coat yourself, at the lowest cost. Uncoated mirrors have no protective layer, so handle them with care before coating.

Product facts

  • Precision Quality Flat Mirrors, Enhanced Aluminum: Coated with Enhanced Aluminum providing Ravg > 90%, 450–2000 nm. Available in Borofloat-33 or Fused Silica. Best for visible and near-IR lasers where you need good reflectivity and a durable coating at a moderate price.

    Precision Quality Flat Mirrors, Enhanced Aluminum

    Precision Quality Flat Mirrors, Enhanced Aluminum

  • Precision Quality Flat Mirrors, Protected Silver: Coated with Protected Silver providing Ravg > 97.5% from 450–2000 nm and Ravg > 97% from 2–10 µm. Ideal for applications demanding maximum reflectivity, including IR lasers beyond 2 µm, but requires careful handling to avoid damaging the protective layer.

    Precision Quality Flat Mirrors, Protected Silver

    Precision Quality Flat Mirrors, Protected Silver

Which coating fits your setup?

Best for

  • Researchers needing high reflectivity in visible to mid-IR (Protected Silver)
  • General lab use with visible or near-IR lasers (Enhanced Aluminum)
  • UV laser applications (UV Enhanced Aluminum)
  • Custom coating projects (Uncoated)

Not for

  • UV wavelengths if you choose Enhanced Aluminum or Protected Silver
  • Mid-IR beyond 10 µm—no coating in this selection covers that range
  • High-power pulsed lasers without checking damage threshold—specifications not provided