N-BAK4 - Schott 2000

Diagram n (λ)

n calculation

Diagram τ (λ)

τ calculation

Analogue search

Main parameters
n_d = 1.568827 n_e = 1.571248	V_d = 55.97 V_e = 55.70	n_F - n_C = 0.010162 n_F' - n_C' = 0.010255	Coloring: 0.36 - 0.33 mkm.

Type: Sellmeier
Spectral range: 0.3650146 - 2.3254 mkm.
C1 = 1.28834642 C2 = 0.132817724 C3 = 0.945395373 C4 = 0.00779980626 C5 = 0.0315631177 C6 = 105.965875

Refraction index
n _2.3254	1.540443
n _1.9701	1.545607
n _1.5296	1.551110
n _1.06	1.556880
n _t	1.557548
n _s	1.560342
n _r	1.564003
n _C	1.565749
n _C'	1.566238
n _0.6328	1.566695
n _D	1.568737
n _d	1.568827
n _e	1.571248
n _F	1.575911
n _F'	1.576493
n _g	1.581487
n _h	1.586144
n _i	1.594150
n _0.3341	-----
n _0.3126	-----
n _0.2967	-----
n _0.2804	-----
n _0.2483	-----

Relative partial dispertion
P_C,t	0.8070
P_C,A'	0.3441
P_d,C	0.3028
P_e,C	0.5411
P_g,d	1.2457
P_g,F	0.5486
P_h,g	0.4582
P_i,g	1.2461
P_C',t	0.8551
P_e,C'	0.4930
P_F',e	0.5161
P_i,F'	1.7375

transmittance: 10 mm
τ_2.5	0.78
τ_2.3254	0.87
τ_1.9701	0.959
τ_1.5296	0.993
τ_1.06	0.998
τ_0.7	0.999
τ_0.66	0.998
τ_0.62	0.998
τ_0.58	0.998
τ_0.54607	0.998
τ_0.5	0.998
τ_0.46	0.996
τ_0.4358	0.995
τ_0.42	0.995
τ_0.4047	0.993
τ_0.4	0.992
τ_0.39	0.987
τ_0.38	0.976
τ_0.37	0.954
τ_0.365	0.93
τ_0.35	0.79
τ_0.3341	0.35

transmittance: 25 mm
τ_2.5	0.54
τ_2.3254	0.71
τ_1.9701	0.9
τ_1.5296	0.982
τ_1.06	0.995
τ_0.7	0.997
τ_0.66	0.995
τ_0.62	0.995
τ_0.58	0.996
τ_0.54607	0.996
τ_0.5	0.994
τ_0.46	0.989
τ_0.4358	0.988
τ_0.42	0.987
τ_0.4047	0.983
τ_0.4	0.98
τ_0.39	0.967
τ_0.38	0.94
τ_0.37	0.89
τ_0.365	0.84
τ_0.35	0.55
τ_0.3341	0.07

Density: 3.05 g/cm³
Poisson coef.: 0.24
Young module: 770 Pa*10⁸
Knoop hardness: 550
Optical stress coef.: 2.9 1/Pa*10¹²
Abrasion: 2

Climatic resistance: 1
Staining: 0
Resistance to acids: 1.2
Resistance to alkalis: 1
Phosphate resistance: 1

Temperature coefficient of linear expansion
Temp. range, C	Value, 1/C*10^-7
-30 ~ 70	70
20 ~ 300	79

Temperature coefs. of n_abs
Temp. range, C	Wave length, mkm.	Value, 1/C*10^-6
-40 ~ -20		0.9
20 ~ 40		1.8
60 ~ 80		2.2
-40 ~ -20	e	1.5
20 ~ 40	e	2.6
60 ~ 80	e	3.1
-40 ~ -20	g	2.2
20 ~ 40	g	3.3
60 ~ 80	g	3.9

Temperature coefs. of n_rel
Temp. range, C	Wave length, mkm.	Value, 1/C*10^-6
-40 ~ -20		3
20 ~ 40		3.1
60 ~ 80		3.3
-40 ~ -20	e	3.7
20 ~ 40	e	3.9
60 ~ 80	e	4.2
-40 ~ -20	g	4.4
20 ~ 40	g	4.7
60 ~ 80	g	5