Refractive Index and Abbe Number
Refractive index and Abbe number values of our fine annealed products vary from catalog value by:
Upon request, we will supply blanks of optical glass to the following tolerances: Refractive index :
We normally send certification (melt data) of refractive indices to the 5th decimal place (six significant digits) measured at each spectral line: C, d, F, g and νd to the1st decimal place, calculated from nd.
Refractive index = ±0.00003 Dispersion = ±0.00002
On request, we shall provide precision measurements of refractive index and dispersion :
Refractive index = ±0.00001 Dispersion = ±0.000003
We will report the environmental temperature, humidity and atmospheric pressure of the room where the precision measurement was undertaken. For, "ultraprecision measurements" and measurements at spectral line not described in this catalog, please contact us.
Refractive index:±0.0003 Dispersion = ±0.00002
On request, we shall provide precision measurements of refractive index and dispersion:
Refractive index:±0.00001 Dispersion = ±0.000003
We will report the environmental temperature, humidity and atmospheric pressure of the room where the precision measurement was undertaken. For, "ultra-precision measurements" and measurements at spectral line not described in this catalog, please contact us.
It is sometimes necessary to measure the index variation across a blank. In such cases, Ohara firmly controls each process and can supply high homogeneity blanks.
Depending on the annealing condition, optical glass retains slight residual strain in most cases. This can be observed as optical birefringence, and measured by optical path differences and specified in nm/cm.
Striae are thread-like veins or cords which can be considered to be parts of different chemical components, of the molten glass.
Bubble & Inclusion
It is most desirable to manufacture bubble-free optical glass, but the existence of bubbles to some extent is inevitable. Bubbles in optical glass vary in size and number from one glass to another due to the many different compositions and production methods. The classifi cation of bubble content is established by specifying in mm2 the total bubble cross sections existing in 100cm3 of glass volume. Inclusions such as small stones or crystals are treated as bubbles.
Variation of coloring between melts is generally within ±10 nm. On special request, we shall report the coloring or the transmission, including reflection losses, of the melt to be supplied by measuring spectral transmission.
We showed each properties as representative value except for above characteristics. Please contact us when you want to know the other value. In addition, please let us know your preferred specification when you place the orders.
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