N-BK7 - Schott 2000

Diagram n (λ)

n calculation

Diagram τ (λ)

τ calculation

Analogue search

Main parameters
n_d = 1.516800 n_e = 1.518721	V_d = 64.16 V_e = 63.96	n_F - n_C = 0.008053 n_F' - n_C' = 0.008109	Coloring: 0.33 - 0.30 mkm.

Type: Sellmeier
Spectral range: 0.3650146 - 2.3254 mkm.
C1 = 1.03961212 C2 = 0.231792344 C3 = 1.01046945 C4 = 0.00600069867 C5 = 0.0200179144 C6 = 103.560653

Refraction index
n _2.3254	1.489211
n _1.9701	1.494948
n _1.5296	1.500906
n _1.06	1.506687
n _t	1.507308
n _s	1.509802
n _r	1.512892
n _C	1.514322
n _C'	1.514719
n _0.6328	1.515089
n _D	1.516727
n _d	1.516800
n _e	1.518721
n _F	1.522376
n _F'	1.522829
n _g	1.526684
n _h	1.530239
n _i	1.536266
n _0.3341	-----
n _0.3126	-----
n _0.2967	-----
n _0.2804	-----
n _0.2483	-----

Relative partial dispertion
P_C,t	0.8709
P_C,A'	0.3586
P_d,C	0.3076
P_e,C	0.5462
P_g,d	1.2272
P_g,F	0.5349
P_h,g	0.4414
P_i,g	1.1897
P_C',t	0.9202
P_e,C'	0.4969
P_F',e	0.5099
P_i,F'	1.6684

transmittance: 10 mm
τ_2.5	0.66
τ_2.3254	0.79
τ_1.9701	0.93
τ_1.5296	0.992
τ_1.06	0.999
τ_0.7	0.998
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	0.997
τ_0.4358	0.997
τ_0.42	0.997
τ_0.4047	0.997
τ_0.4	0.997
τ_0.39	0.996
τ_0.38	0.993
τ_0.37	0.99
τ_0.365	0.988
τ_0.35	0.967
τ_0.3341	0.9
τ_0.32	0.66
τ_0.31	0.35

transmittance: 25 mm
τ_2.5	0.36
τ_2.3254	0.56
τ_1.9701	0.84
τ_1.5296	0.98
τ_1.06	0.997
τ_0.7	0.996
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	0.993
τ_0.4358	0.992
τ_0.42	0.993
τ_0.4047	0.993
τ_0.4	0.992
τ_0.39	0.989
τ_0.38	0.982
τ_0.37	0.975
τ_0.365	0.971
τ_0.35	0.92
τ_0.3341	0.77
τ_0.32	0.36
τ_0.31	0.07

Density: 2.51 g/cm³
Poisson coef.: 0.206
Young module: 820 Pa*10⁸
Knoop hardness: 610
Optical stress coef.: 2.77 1/Pa*10¹²
Abrasion: 3

Climatic resistance: 2
Staining: 0
Resistance to acids: 1
Resistance to alkalis: 2
Phosphate resistance: 2.3

Temperature coefficient of linear expansion
Temp. range, C	Value, 1/C*10^-7
-30 ~ 70	71
20 ~ 300	83

Temperature coefs. of n_abs
Temp. range, C	Wave length, mkm.	Value, 1/C*10^-6
-40 ~ -20		0.3
20 ~ 40		1.1
60 ~ 80		1.5
-40 ~ -20	e	0.8
20 ~ 40	e	1.6
60 ~ 80	e	2.1
-40 ~ -20	g	1.2
20 ~ 40	g	2.1
60 ~ 80	g	2.7

Temperature coefs. of n_rel
Temp. range, C	Wave length, mkm.	Value, 1/C*10^-6
-40 ~ -20		2.4
20 ~ 40		2.4
60 ~ 80		2.5
-40 ~ -20	e	2.9
20 ~ 40	e	3
60 ~ 80	e	3.1
-40 ~ -20	g	3.3
20 ~ 40	g	3.5
60 ~ 80	g	3.7