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Optical constants of SCHOTT - BK (Borosilicate crown)
SCHOTT N-BK7®

Wavelength: µm
 (0.3–2.5)  
 

Complex refractive index (n+ik)[ i ]


n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula [ i ]

$$n^2-1=\frac{1.03961212λ^2}{λ^2-0.00600069867}+\frac{0.231792344λ^2}{λ^2-0.0200179144}+\frac{1.01046945λ^2}{λ^2-103.560653}$$

Conditions & Spec sheet

n_is_absolute: false
wavelength_is_vacuum: false
temperature: 20.0 °C
thermal_dispersion:
  - type: "Schott formula"
    coefficients: 1.86e-06 1.31e-08 -1.37e-11 4.34e-07 6.27e-10 0.17
nd: 1.5168
Vd: 64.17
glass_code: 517642.251
glass_status: standard
density: 2.51 g/cm3
thermal_expansion:
  - temperature_range: -30 70 °C
    coefficient: 7.1e-06 K-1
  - temperature_range: 20 300 °C
    coefficient: 8.3e-06 K-1
dPgF: -0.0009
climatic_resistance: 1.0
stain_resistance: 0.0
acid_resistance: 1.0
alkali_resistance: 2.3
phosphate_resistance: 2.3

Comments

step 0.5 available

References

SCHOTT Zemax catalog 2017-01-20b (obtained from http://www.schott.com)
See also SCHOTT glass data sheets

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


SCHOTT AG

SCHOTT AG is a German multinational company renowned for its expertise in specialty glass and glass-ceramics. Founded in 1884, the company has been a pioneer in the field, with innovations that have significantly impacted a variety of industries, including healthcare, home appliances, electronics, and optics. In the optical domain, SCHOTT offers a comprehensive range of high-quality glass types, including crown and flint glasses, as well as specialty materials like laser glasses and radiation-shielding glasses. These materials are used in a myriad of applications, from consumer electronics and camera lenses to scientific instruments and aerospace technologies. SCHOTT's glass products are highly regarded for their quality, consistency, and durability, meeting rigorous industry standards. With a strong focus on research and development, the company has continued to introduce innovative products that address the evolving needs of the optical industry. SCHOTT's commitment to quality and innovation has established it as a leading provider of specialty glass solutions, making it a go-to choice for designers and manufacturers seeking high-performance materials. SCHOTT also publishes a glass catalog (SCHOTT Optical Glass Datasheets), which is a standard reference for the properties of many optical glasses.

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.

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