H-FK55 by CDGM

Preferred Common Environmentally Friendly

H-FK55 by CDGM is a preferred optical glass with a common melt frequency. It transmits from 0.28 to 2.40 µm with an nd of 1.5502 and a Vd of 75.224681. It has high thermal expansion (CTE of 11.4×10⁻⁶/K), excellent chemical resistance, and high relative cost.

Refractive Index vs Wavelength
Refractive Index Calculator
Valid range: 0.302–2.325 µm
dn/dλ vs Wavelength
dn/dλ Calculator
Valid range: 0.302–2.325 µm
Abbe Number Calculator
Transmission vs Wavelength
Transmission Calculator
Valid wavelength range: 0.280–2.400 µm
Optical Properties
Refractive Index (nd) 1.5502
Abbe Number (Vd) 75.224681
Dispersion Formula Sellmeier
Wavelength Range 0.302 — 2.325 µm
$$n(\lambda) = \sqrt{1 + \frac{0.534932\,\lambda^2}{\lambda^2 - 0.00128059} + \frac{0.83905\,\lambda^2}{\lambda^2 - 0.0116445} + \frac{0.886512\,\lambda^2}{\lambda^2 - 143.252}}$$
Thermal Properties
TCE -30/70°C (10-6/K) 11.4
TCE 100/300°C (10-6/K) 14.3
Thermal Conductivity (W/mK) 0.536
Heat Capacity (J/gK) 0.472
$$\frac{dn}{dT} = \frac{n_0^2 - 1}{2\,n_0}\left[-1.79 \times 10^{-5} + 2(5.97 \times 10^{-9})\,\Delta T + 3(-4.11 \times 10^{-11})\,\Delta T^2 + \frac{3.16 \times 10^{-7} + 2(2.18 \times 10^{-10})\,\Delta T}{\lambda - 0.217}\right] \Delta T = T - T_0, \quad T_0 = 20\,°\text{C}$$
Physical Properties
Density (g/cm³) 4.11
Relative Cost 15.1
Mechanical Properties
Young's Modulus (GPa) 76.83
Poisson's Ratio 0.297
Knoop Hardness (kgf/mm²) 405.0
Chemical Resistance
Climatic Resistance 1
Stain Resistance —
Acid Resistance —
Alkali Resistance —
Phosphate Resistance —
Similar Glasses (Other Manufacturers)
Glass Manufacturer nd Vd Compare
FCD705 Hoya 1.55032 75.5
ULTRAN30 Schott 1.5483 74.244488
S-FPM3 Ohara 1.53775 74.703119
B42-73 Corning 1.542198 73.473057
S-FPM4 Ohara 1.52841 76.452824
K-PSK500 Sumita 1.55215 72.0
K-PSK500(M) Sumita 1.55 71.9
B58-72 Corning 1.558086 71.998499
B29-77 Corning 1.528554 76.961514
PK51A Schott 1.528554 76.975515
Similar Glasses (CDGM)
Glass Manufacturer nd Vd Compare
H-ZPK7 CDGM 1.56907 71.304254
D-ZPK7 CDGM 1.56907 71.304254
D-ZPK7-25 CDGM 1.56854 71.235367
D-PK3 CDGM 1.525 70.370578
D-PK3-25 CDGM 1.52368 70.274839
D-ZPK5-25 CDGM 1.59216 68.281511
H-ZPK5 CDGM 1.5928 68.342024
D-ZPK5 CDGM 1.5928 68.342024
D-FK61A-25 CDGM 1.49665 81.549116
D-FK61-25 CDGM 1.49653 81.531772
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