KT (KTaO₃) Crystal

• Transparent optical crystal composed of Kalium (K), Tantalum (Ta) and Oxygen (O)
• Optically isotropic cubic crystal in the range of 365nm - 4000nm
• Achieving very high refractive index in the range of visible region (Refractive index is more than - 2.2)
• Very stable against thermal condition and humidity

KT crystal composition (cubic crystal)

• Chemically stable and transparent optical crystal
• No birefringence in the range of 365nm - 4000nm
• Very high refractive index (nd = 2.24257)

Suitable material for the following applications

1. Various lens due to its high refractive index and transparency
2. SIL (Solid Immersion Lens) for next generation optical data storage unit (Please find the reference thesis)
3. Optical components for laser (such as Er:YAG) by utilizing its high transparency and high optical damage threshold
4. NAIL (Numerical Aperture Increasing Lens) of microscope

Application example as polished ball lens

Please contact us any time if you have any specific requirements for
ball lens, SIL and NAIL and etc.

Optical performances

Refractive Index

In-line trancemittance

Material Properties

• Refractive Index
  nd = 2.24257 (@ 28 centigrade)
• Linear Coefficient of Thermal Expansion
  -30 centigrade to +20 centigrade : 6.3 × 10-6 / centigrade
  +20 centigrade to +70 centigrade : 6.7 × 10-6 / centigrade
• Abbe-Number
  vd = 17.3 (@ 28 centigrade)
• Wide optical window
  365nm to 4,000nm
• Good machinability
  Weak cleavage habit : no chipping
  Knoop Hardness : 470

Masataka Shinoda, Kimihiro Saito, Takao Kondo, Motohiro Furuki, Minoru Takeda and Ariyoshi Nakaoki, Masahiro Sasaura and Kazuo Fujiura

High-Density Near-Field Readout using a Solid Immersion Lens of KTaO₃

2005 ISOM/ODS WD3
(International Symposium on Optical Memory and Optical Data Storage)