OHARA INC. : Measurement of refractive indices of solid and liquid

$Measurement of refractive indices of solid and liquid$

Measuring method, range of wavelength measurable, and the accuracy will be different according to the size and the shape of the test piece.

Measurement of refractive indices of solid

Chart1 : Examples of measurements and the methods

Material characteristics	Measuring materials	Measuring method
Isotropic materials	Optical glass, Silica glass, etc.	Refractometer (V-Block method) or Spectrometer (Minimum deviation method)
	Crystals of cubic system(CaF₂,Si,ZnS,ZnSe,etc)
	Plastics (without birefringence)	Refractometer (V-Block Method)
	Porous Glasses (n1.03)	Spectrometer (Minimum deviation method)
Anisotropy materials	Uniaxial crystals(Quartz,TiO₂,Sapphire,LBO,Ice, etc)	Spectrometer (Minimum deviation method) Refractometer (V-Block method)
Anisotropy materials	Plastics with birefringence	Refractometer (V-Block method)

Please refer Chart 2 for spectral lines measurable and the accuracy of the measurements.

Chart2 : Spectral lines measurable and the accuracy

Spectral lines				Measuring Equipment
Spectral lines				MÖLLERWEDEL			Carl Zeiss Jena
Wavelength		Symbols	Symbols of lamps (Light source)	Super Precision Spectro meter Type1		Precision Spectro meter Type 2	Refracto meter Type PR-2
Wavelength				Ultra precision	Precision	Standard	Standard
in air (nm)	in vacuum (nm)			Measuring Accuracy (10^-6)	Measuring Accuracy (10^-5)	Measuring Accuracy (10^-5)	Measuring Accuracy (10^-5)
2325.42	2326.05		Hg	±5	±1	×	×
2058.09	2058.65		He	±5	±1	×	×
1970.09	1970.63		Hg	±5	±1	×	×
1813.07	1813.57		Hg	±5	±1	×	×
1529.58	1530.00		Hg	±5	±1	×	×
1128.64	1128.95		Hg	±3	±1	×	×
1013.98	1014.26	t	Hg	±1	±1	±3	±5
852.110	852.344	s	Cs	±1	±1	±3	±5
780.023	780.237		Rb	±1	±1	±3	±5
706.519	706.714	r	He	±1	±1	±3	±5
656.273	656.454	C	H₂	±1	±1	±3	±3
643.847	644.025	C'	Cd	±1	±1	±3	±3
632.82	632.99		He- Ne	±1	±1	±3	±3
587.562	587.725	d	He	±1	±1	±3	±3
546.075	546.227	e	Hg	±1	±1	±3	±3
486.133	486.269	F	H₂	±1	±1	±3	±3
479.992	480.126	F'	Cd	±1	±1	±3	±3
435.835	435.957	g	Hg	±1	±1	±3	±3
404.656	404.770	h	Hg	±1	±1	±3	±5
388.865	388.975		He	±1	±1	±3	×
365.015	365.119	i	Hg	±1	±1	±3	×
340.365	340.463		Cd	±3	±1	×	×
334.148	334.244		Hg	±3	±1	×	×
312.566	312.657		Hg	±3	±1	×	×
296.728	296.814		Hg	±3	±1	×	×
289.360	289.444		Hg	±3	±1	×	×
253.652	253.728		Hg	±3	±1	×	×
228.802	228.872		Cd	±3	±1	×	×
226.502	226.572		Cd	±3	±1	×	×
214.438	214.506		Cd	±3	±1	×	×
213.856	213.923		Zn	±3	±1	×	×
206.200	206.266		Zn	±3	±1	×	×
202.548	202.613		Zn	±3	±1	×	×
-	194.227		Hg	±5	±1	×	×
-	184.950		Hg	±5	±1	×	×

Chart3 : Examples of measurements and the methods

Condition of test materials	Example of measurement	Measuring method
Thin film (Several microns in thickness needed)	Thin film coated on glass substrates Silicon oxide film on silicon wafer	By refractometer (Critical angle method, Prism coupling method, etc.)
Surface layer (Several microns in thickness needed)	Chemically strengthened surface layer

Wavelengths used for the measurements:633nm, d, e, & g
Measuring accuracy:±1×10^-3~±1×10^-4

Chart4 : Examples of measurements and the methods

Particle diameter	Example of measurement	Measuring method
Several microns ~ 30 microns	White powder of glasses and rocks	Becke method

Wavelengths used for the measurements:633nm, D, e, & g
Available measurement range:n_D=1.43~1.73
ng=1.43~1.78
Measuring accuracy:±1×10^-3

Chart5 : Examples of measurements and the methods

Condition of test material	Example of measurement	Measuring method
Liquid like	Oil, Alcohol, Water, Gasoline, etc.	Refractometer (V-Block method)
Greasy	Greasy oil
Jelly	Adhesive

Wavelengths used for the measurements:795nm, 780nm, C, C', 633nm, d, e, F, F', & g
Measuring accuracy:±3×10^-4~±5×10^-5