Optical medium, an optical lens and a prism
AssigneeNippon Telegraph and Telephone Corporation
InventorsKazuo Fujiura, Tadayuki Imai, Masahiro Sasaura, Kouichirou Nakamura
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Abstract
An optical medium having a high refractive index without anisotropy and a wide transmission wavelength is obtained. The cubic crystal material is αβO3, where α is at least one of K, Ba, Sr, Ca, and β is at least one of Ta, Ti. Optimally, the cubic crystal material is KTa1-xNbxO3, where composition x is 0≦x≦0.35. This composition enables to raise refractive index while its phase transition temperature is below a room temperature.
Claims3
An optical medium comprising a cubic crystal comprising KTaO3-d, where the amount of oxygen deficiency d is 10−8≦d<10−7 controlled based on a monotonically increasing relationship between the oxygen deficiency and an absorption coefficient.
An optical lens comprising:
- a cubic crystal material comprising KTaO3-d, where the amount of oxygen deficiency d is 10−8≦d<10−7 controlled based on a monotonically increasing relationship between the oxygen deficiency and an absorption coefficient;
- and
- a refractive index of more than 2.2 in the wavelength range of 360 nm-800 nm, and a transmission of 80% or more with a 10 mm thickness.
An optical prism comprising:
- a cubic crystal material comprising KTaO3-d, where the amount of oxygen deficiency d is 10−8≦d<10−7 controlled based on a monotonically increasing relationship between the oxygen deficiency and an absorption coefficient;
- and
- a refractive index of more than 2.2 in the wavelength range of 360 nm-800 nm, and a transmission deterioration of 1% or less under a 10-minute irradiation with an irradiation intensity of 2.2 W/cm2.
Dependencies are inferred from the claim text.