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See all 206 Products in Family

TECHSPEC^® components are designed, specified, or manufactured by Edmund Optics. Learn More

20mm Dia., 3mm Thick, VIS-NIR Coated λ/4 N-BK7 Window

Stock #45-660

$70.00 Other Coating Options

Qty 1-5
$70.00

Qty 6+
$56.00

Volume Pricing
Request Quote

Curve eDrawing: eprt IGES PDF Drawing STEP: step

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Abbe Number (v_d):

64.17

Bevel:

Protective as needed

Clear Aperture (%):

Clear Aperture CA (mm):

18.00

Diameter (mm):

20.00 +0.0/-0.25

Thickness (mm):

3.00 ±0.20

Coating:

VIS-NIR (400-1000nm)

Coating Specification:

R_abs ≤0.25% @ 880nm
R_avg ≤1.25% @ 400 - 870 nm
R_avg ≤1.25% @ 890 - 1000nm

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

7.1 (-30 to +70°C)
8.3 (+20 to +300°C)

Density (g/cm³):

2.51

Edges:

Fine Ground

Index of Refraction n_d:

1.516

Knoop Hardness (kg/mm²):

610

Parallelism (arcmin):

≤1

Poisson's Ratio:

0.206

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

N-BK7

Surface Flatness:

λ/4

Surface Quality:

60-40

Type:

Protective Window

Typical Energy Density Limit:

5 J/cm² @ 532nm, 10ns

Wavelength Range (nm):

400 - 1000

Young's Modulus (GPa):

Regulatory Compliance

RoHS 2015:

Compliant

Reach 211:

Compliant

Product Family Description

λ/4 Surface Flatness
Broadband Anti-Reflection Coating Options Available
Custom Coatings and Sizes Available for Volume OEM Quantities
Also Available with Laser Line V-Coats

TECHSPEC® λ/4 N-BK7 Precision Windows are ideally suited for industrial and low power laser applications. The high tolerance design yields minimal beam distortion and scatter. Broadband coating options extend the range of these precision windows through the visible and near-infrared spectra.

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