Name: 40mm Dia., 4mm Thick, NIR II Coated λ/4 N-BK7 Window
Brand: TECHSPEC
SKU: 25-819
Price: ₹9,775.00

40mm Dia., 4mm Thick, NIR II Coated λ/4 N-BK7 Window

Abbe Number (v_d):

64.17

Bevel:

Protective as needed

Clear Aperture (%):

Clear Aperture CA (mm):

36.00

Diameter (mm):

40.00 +0.00/-0.25

Thickness (mm):

4.00 ±0.20

Coating:

NIR II (750-1550nm)

Coating Specification:

R_abs ≤1.5% @ 750 - 800nm
R_abs ≤1.0% @ 800 - 1550nm
R_avg ≤0.7% @ 750 - 1550nm

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):

Poisson's Ratio:

0.206

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

N-BK7

Surface Flatness (P-V):

λ/4

Surface Quality:

60-40

Type:

Protective Window

Typical Energy Density Limit:

8 J/cm² @ 1064nm, 10ns

Wavelength Range (nm):

750 - 1550

Young's Modulus (GPa):

Type of Window:

Glass

8 J/cm² @ 1064nm, 10ns

Regulatory Compliance

RoHS:

Compliant

Certificate of Conformance:

View

Product Family Description

Circular and Square Sizes from 5mm to 150mm
6 Broadband Anti-Reflection Coating Options Available
World's Largest selection of Standard N-Bk7 Windows
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.

Note: New additions to this product family may be specified with a transmitted wavefront distortion (TWD) specification instead of a surface flatness. For more information on the difference between these two specifications, see our application note on Understanding Optical Windows.