4" Dia. λ/20 Fused Silica Dual Surface Flat

Surface Flatness (P-V):

λ/20

Abbe Number (v_d):

67.8

Clear Aperture CA (mm):

91.40

Coating:

Uncoated

Coefficient of Thermal Expansion CTE (10^-6/°C):

0.52 (+5 to +35°C)
0.57 (0 to +200°C)
0.48 (-100 to +200°C)

Diameter (mm):

101.60 ±1.0

Diameter (inches):

4.00 ±0.04

Thickness (inches):

0.75 ±0.06

Construction:

Dual Surface

Density (g/cm³):

2.20

Index of Refraction n_d:

1.458

Knoop Hardness (kg/mm²):

522

Parallelism (arcmin):

≤1

Poisson's Ratio:

0.16

Thickness (mm):

19.05 ±1.5

Substrate: Many glass manufacturers offer the same material characteristics under different trade names. Learn More

Fused Silica (Corning 7980)

Surface Quality:

60-40

Type:

Interferometry Window

Wavelength Range (nm):

200 - 2200

Young's Modulus (GPa):

Bevel:

Protective as needed

Regulatory Compliance

RoHS 2015:

Compliant

Reach 197:

Compliant

Certificate of Conformance:

View

Product Description

λ/20 flats include a certificate of calibration.

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