BAK1 by Sumita

Obsolete Very Rare Environmentally Dangerous

BAK1 by Sumita is an obsolete optical glass with a very rare melt frequency. It transmits from 0.29 to 2.00 µm with an nd of 1.5725 and a Vd of 57.5. It has good chemical resistance and dangerous environmental properties.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.27–2.0 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.27–2.0 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.290–2.000 µm
Optical Properties
Refractive Index (nd) 1.5725
Abbe Number (Vd) 57.5
Dispersion Formula Schott
Wavelength Range 0.27 — 2.0 µm
$$n(\lambda) = \sqrt{2.43358 - 0.00887169\,\lambda^2 + 0.0138279\,\lambda^{-2} + 0.000267576\,\lambda^{-4} - 4.11763 \times 10^{-6}\,\lambda^{-6} + 4.82973 \times 10^{-7}\,\lambda^{-8}}$$
Thermal Properties
TCE -30/70°C (10-6/K) —
TCE 100/300°C (10-6/K) 8.9
Thermal Conductivity (W/mK) —
Heat Capacity (J/gK) —
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[0 + 2(0)\,\Delta T + 3(0)\,\Delta T^2 + \frac{0 + 2(0)\,\Delta T}{\lambda - 0}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 3.18
Relative Cost —
Mechanical Properties
Young's Modulus (GPa) —
Poisson's Ratio —
Knoop Hardness (kgf/mm²) —
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance 2
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
B72-57 Corning 1.572498 57.494511
BAC1 Hoya 1.572497 57.488684
H-BAK8 CDGM 1.5725 57.486797
BAK1 Schott 1.5725 57.54931
N-BAK1 Schott 1.5725 57.55
S-BAL11 Ohara 1.572501 57.74298
BAL11 Ohara 1.572501 57.760854
BAK50 Schott 1.567736 57.990411
BAC6 Hoya 1.574441 56.357089
S-BAL14 Ohara 1.568832 56.363897
Similar Glasses (Sumita)
Glass Manufacturer nd Vd Compare
K-CSK158(M) Sumita 1.58157 56.7
BAK4 Sumita 1.56883 56.0
K-CSK158 Sumita 1.584 56.9
K-SKLD200(M) Sumita 1.58355 58.8
SK12 Sumita 1.58313 59.3
K-CSK120(M) Sumita 1.58445 59.2
K-SKLD200 Sumita 1.5866 59.0
K-SKLD120(M) Sumita 1.58401 59.5
CSK12 Sumita 1.5865 59.6
CSK120 Sumita 1.587 59.6
Compare Glasses
    Compare Selected