RefractiveIndex.INFO

Refractive index database

nk database   |   n2 database   |   about

Shelf

Book

Page

Optical constants of SUMITA - BK (Borosilicate crown)
K-BK7

Wavelength: µm
 (0.290–2.000)  
 

Complex refractive index (n+ik)[ i ]


n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula

$$n^2=2.2705778-0.010059376λ^{2}+0.010414999λ^{-2}+0.00028872517λ^{-4}-2.2214495\text{×}10^{-05}λ^{-6}+1.4258559\text{×}10^{-06}λ^{-8}$$

Conditions & Spec sheet

n_is_absolute: false
wavelength_is_vacuum: false
temperature: 20.0 °C
thermal_dispersion:
  - type: "Schott formula"
    coefficients: 6.84e-07 2.05e-08 -1.55e-10 4.18e-07 2.74e-10 0.178
nd: 1.51633
Vd: 64.1
glass_code: 516641
density: 2.52 g/cm3
thermal_expansion:
  - temperature_range: -30 70 °C
    coefficient: 6.3e-06 K-1
  - temperature_range: 20 300 °C
    coefficient: 8.5e-06 K-1
dPgF: -0.0014
climatic_resistance: 1.0
acid_resistance: 1.0

References

SUMITA Zemax catalog 2017-02-02 (obtained from http://www.sumita-opt.co.jp)
See also SUMITA optical glass data book

Data

[Expressions for n]   [CSV - comma separated]   [TXT - tab separated]   [Full database record]

INFO

BK7 optical glass

BK7 is a widely used optical glass known for its high transmission and clear, colorless appearance. Composed primarily of silica and boron oxide, BK7 is popular in a broad range of optical applications, including lenses, prisms, and windows. It exhibits good mechanical properties and can be easily polished to a high optical quality. While it is not as resistant to thermal shock or chemical corrosion as some specialized glasses like borosilicate or fused silica, it is considerably less expensive, making it a cost-effective choice for many applications. Its relatively high refractive index and low dispersion make it suitable for a variety of optical systems, particularly those operating in the visible spectrum. Because of its versatility and cost-effectiveness, BK7 is often considered the "go-to" material for general-purpose optical components.

Analogs of BK7 glass produced by different makers

Maker Glass
SCHOTT N-BK7
OHARA S-BSL7
HIKARI J-BK7A
CDGM H-K9L
HOYA BSC7
SUMITA K-BK7
LZOS K8

External links


SUMITA Optical Glass, Inc.

SUMITA Optical Glass, Inc. is a Japanese corporation known for its specialization in the production and development of optical glass, optical fiber, and various other photonic products. Founded in 1953, the company has established itself as a leading provider of high-quality optical materials that are used in a wide range of applications—from industrial and scientific optics to consumer electronics and medical devices. SUMITA's portfolio includes a variety of specialized optical glasses, including high-refractive-index, low-dispersion, and infrared-transmitting materials. These are often utilized in lenses, prisms, and other optical components requiring precision and high performance. With a strong commitment to research and development, SUMITA continually innovates to meet the evolving demands of the optics industry. Their rigorous quality control processes ensure that products meet the highest standards for optical clarity, consistency, and reliability. SUMITA Optical Glass, Inc. has garnered a reputation for excellence and innovation, making it a preferred supplier for organizations in need of advanced optical solutions.

External links


Glass

Glass is a versatile, amorphous material that has been an essential component in optical technologies for centuries. Comprising mainly of silica along with various additives like soda, lime, or boron, glass can be engineered to exhibit a wide range of optical properties, such as refractive indices and dispersion characteristics. In the optical industry, specialized types of glass like crown, flint, and extra-low dispersion (ED) glasses are used for manufacturing lenses, prisms, and other optical elements. These glasses are precisely formulated to offer specific properties, such as low chromatic aberration or high light transmittance across different spectral ranges. Glass can also be coated with thin layers of materials like anti-reflective coatings to enhance its optical performance. More recently, advances in photonics and nanotechnology have led to the development of innovative glass types, such as photonic crystal and metamaterial glasses, which exhibit unique light-manipulating properties. It is crucial to note that the optical properties of glass, including its refractive index, can vary depending on its composition and temperature, making it important to consult specific data for particular applications. Overall, glass remains a foundational material in optics, its wide applicability owed to its tunable properties and general robustness.

External links