Optical constants of BK7
S-BSL7 (OHARA)
Wavelength:
µm
(0.29–2.4)
Complex refractive index (n+ik)
n
k
LogX
LogY
eV
Derived optical constants
Dispersion formula
$$n^2-1=\frac{1.1515019λ^2}{λ^2-0.010598413}+\frac{0.118583612λ^2}{λ^2+0.011822519}+\frac{1.26301359λ^2}{λ^2-129.617662}$$Conditions & Spec sheet
n_is_absolute: false
wavelength_is_vacuum: false
temperature: 25.0 °C
thermal_dispersion:
- type: "Schott formula"
coefficients: 1.7e-06 1.43e-08 -4.27e-11 4.08e-07 6.74e-10 0.201
nd: 1.516330
Vd: 64.142022
glass_code: 516641
density: 2.52 g/cm3
thermal_expansion:
- temperature_range: -30 70 °C
coefficient: 7.2e-06 K-1
- temperature_range: 20 300 °C
coefficient: 8.6e-06 K-1
dPgF: -0.0024
climatic_resistance: 1.0
acid_resistance: 1.0
phosphate_resistance: 2.0
Comments
Recommended
References
OHARA Zemax catalog 2017-11-30 (obtained from http://www.ohara-inc.co.jp)
See also OHARA glass data sheets
Data
INFO
Ohara Group
Ohara Group is an international group of companies with headquarters in Japan and subsidiaries in Japan (Ohara, Inc.), United States (Ohara Corporation), and Germany (Ohara, GmbH). Ohara is known for its specialization in high-quality optical glass, ceramics, and other advanced materials. With a history spanning over a century, Ohara has been at the forefront of optical innovations, producing a wide range of specialized glass types including low-dispersion and high-refractive-index materials. These are used in various demanding applications like telescopes, microscopes, and high-performance camera lenses. The company's commitment to research and development has led to groundbreaking products such as low thermal expansion glass-ceramics and other specialty materials used in semiconductor manufacturing and space telescopes. With stringent quality control procedures, Ohara ensures that its optical glass meets the highest standards of clarity, consistency, and performance. Their materials are widely regarded for their exceptional quality and are often used in scientific research, aerospace, and other fields where precision and reliability are paramount. Ohara's reputation for technical excellence and innovation makes it a key player in the global optics and materials science industries, providing cutting-edge solutions for a range of complex applications.External links
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 |