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Femtoline Low GDD Ultrafast Mirrors

Laser mirrors for femtosecond applications are designed to have a broad operating wavelength range and linear phase versus frequency characteristics (low group delay dispersion (GDD)). The coating is a single layer dielectric and has no phase shift over the operating wavelength region.

High reflectivity mirrors always have higher reflection, broader operating region and lower pulse distortion for s-polarization than for p-polarization for the same dielectric coating. If possible use the mirrors with s-polarized beam.

Our standard mirrors are suitable for fundamental Ti:Sapphire and Yb:KGW/KYW lasers and their doubled, tripled or quadrupled frequencies. Recommended for high power laser applications operating in UV region.

UV grade Fused Silica or BK7 glass
S1 Surface Flatness
λ/10 at 633 nm
S1 Surface Quality
20-10 scratch & dig (MIL-PRF-13830B)
S2 Surface Quality
Commercial polish
Diameter Tolerance
+0.00 mm-0.12 mm
Thickness Tolerance
<3 min
0.3 mm at 45° typical


Electron beam multilayer dielectric or Ion Beam Sputtering
Adhesion and Durability
Per MIL-C-675A. Insoluble in lab solvents
Clear Aperture
Exceeds central 85% of diameter
Hard dielectric High Reflection R>99.5%
Designed for Average Polarization
Laser Damage Threshold >100 mJ/cm2, 50 fsec, 50 Hz, 800 nm typical
Coated Surface Flatness λ/10 at 633 nm over clear aperture
Angle of Incidence 0 or 45±3 degrees