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		MATERIAL		BASE PROPERTIES		REFRACTIVE INDEX		PRODUCTS AVAILABLE

Borosilicate Crown Glass (BK-7)

Relative
partial dispersion

P(s,t)	0.3098
P(C,s)	0.5612
P(d,C)	0.3076
P(e,d)	0.2386
P(g,F)	0.5349
P(i,h)	0.7483
P'(s,t)	0.3076
P'(C',s)	0.6062
P'(d,C')	0.2566
P'(e,d)	0.2370
P'(g,F')	0.4754
P'(i,h)	0.7432

wavelength, nm


		MATERIAL		BASE PROPERTIES		REFRACTIVE INDEX		PRODUCTS AVAILABLE




	PARAMETER	VALUE


	Refractive Index	n_d = 1.51680; n_e = 1.51872
	Reflection Loss	8.3% at 588nm (2 surfaces)
	Abbe Constant	n_d = 64.17; n_e= 63.96
	Principal Dispersion	n_F – n_C = 0.008054 n_F' - n_C' = 0.008110
	Density	2.51 g/cm³
	Thermal Conductivity	1.114 W/(m*K)
	Specific Heat Capacity	0.858 J/(g*K)
	Coefficient of Expansion	a (-30/+70°C) = 7.1? 10^-6/K a (20/300°C) = 8.3? 10^-6/K
	Transformation Temperature, T_g	557°C
	Temperature of the glass at a viscosity of 10¹³ dPa? s	557°C
	Temperature of glass in at a viscosity of 10^7.6 dPa s	719°C
	Elasticity Modulus	82 x 10³ N/mm²
	Poisson's Ratio	0.206
	Stress optical coefficient	2.77 x 10^-6 mm²/N
	Knoop hardness (0.1/20)	610
	Bubble class	0
	Climatic resistance	2
	Stain resistance	0
	Acid resistance	1
	Alkali resistance	2.0
	Phosphate resistance	2.3
	Melting Frequency	I


		MATERIAL		BASE PROPERTIES		REFRACTIVE INDEX		PRODUCTS AVAILABLE


		MATERIAL		BASE PROPERTIES		REFRACTIVE INDEX		PRODUCTS AVAILABLE

Wavelength, nm	2325.4	1970.1	1529.6	1060.0	1014.0	852.1	706.5
Refractive Index	1.489	1.495	1.501	1.507	1.507	1.510	1.513

Wavelength, nm	656.3	643.8	632.8	589.3	587.6	546.1	486.1
Refractive Index	1.514	1.515	1.515	1.517	1.517	1.519	1.522

Wavelength, nm	480.0	435.8	404.7	365.0	334.1	312.6
Refractive Index	1.523	1.527	1.530	1.536	1.543	1.549

Temperature Coefficients of Refractive Indices

	dn_rel/dT, 10^-6/K			dn_abs/dT, 10^-6/K
°C	1060.0 nm	e	g	1060.0 nm	e	g
-40/-20	2.4	2.9	3.3	0.3	0.8	1.2
+20/+40	2.4	3.0	3.5	1.1	1.6	2.1
+60/+80	2.5	3.1	3.7	1.5	2.1	2.7


		MATERIAL		BASE PROPERTIES		REFRACTIVE INDEX		PRODUCTS AVAILABLE

The following products from BK-7 are available:

  WINDOWS

  BLANKS

  LENSES
   (spherical pl-cvx, spherical bi-cvx, cylindrical pl-cvx)

  PRISMS

CRYSTALTECHNO

Crystal Optics Manufacturer

MATERIALS:

BK-7

Fluorides

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