Refractive index database

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Optical constants of BAK1

Wavelength: µm

Complex refractive index (n+ik)[ i ]

n   k   LogX   LogY   eV

Derived optical constants

Dispersion formula


Conditions & Spec sheet

n_is_absolute: false
wavelength_is_vacuum: false
temperature: 23.0 °C
  - type: "Schott formula"
    coefficients: 1.5631e-06 2.1447e-08 -8.7901e-13 5.3404e-07 3.4943e-10 0.18343
nd: 1.572500
Vd: 57.291343
density: 3.17 g/cm3
  - temperature_range: -30 70 °C
    coefficient: 7.3e-06 K-1
dPgF: -0.0011
phosphate_resistance: 2.0


NIKON Zemax catalog 2017-11 (obtained from
See also HIKARI glass data sheets


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Hikari Glass Co., Ltd.

Hikari Glass Co., Ltd. is a Japanese company specializing in the manufacturing of high-quality optical glass and optical components, and is a subsidiary of Nikon Corporation. Known for its precision engineering and strict quality control, Hikari serves various industries including consumer electronics, scientific research, and industrial optics. The company offers a wide range of specialized optical materials, including various types of crown and flint glasses, which are used in applications demanding high levels of optical clarity and performance. Hikari's products often find use in lenses, prisms, and other optical elements where precision and reliability are critical. With the backing of Nikon's renowned expertise in optics and imaging, Hikari has become a respected name in the field of optics, serving both domestic and international markets. Their expertise in crafting custom solutions for complex optical requirements has made them a preferred choice for organizations in need of specialized glass materials. As a testament to their commitment to quality, Hikari Glass Co., Ltd. is often sought after for projects requiring the highest levels of optical performance and integrity.

External links

BAK1 optical glass

BAK1 (Borosilicate Crown 1) is a type of optical glass that combines boron and silicate, among other elements, to achieve specific optical properties. This glass type is often used in specialized optical applications that require low dispersion and a high refractive index. BAK1 is known for its good transmission across the visible spectrum and into the near-infrared range, making it suitable for a variety of optical devices like telescopes, binoculars, and certain types of lenses. Its low level of optical aberrations makes it a choice material for high-quality imaging systems. Like other high-quality optical glasses, BAK1 can be expensive and is generally used in applications where its particular optical characteristics offer a noticeable advantage. Overall, BAK1 represents a specialized category of optical glass, designed for applications requiring high performance and specific optical properties.

BAK1 or similar glasses produced by different makers

Maker Glass
Schott N-BAK1
Hikari E-BAK1
Ohara S-BAL11


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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