Optical Measurement Services - Refractive Index, Dispersion and dN/dT

M³ Measurement Solutions Inc. utilises a modified minimum deviation process to provide refractive index testing and dn/dT at temperature ranges from -196.15°C (77°K) to +100 °C (373.15°K) and wavelengths from 350nm to 14um. Dewar vacuum is nominally held to 1e-4 Torr. This process incorporates good thermally conductive fixturing with well controlled ramp rates and soak times to ensure thermal stability of the sample for accurate measurements. They use a half prism configuration for this process to achieve a nominal 30 degree refracted angle.

Optical materials which can benefit from such measurements include Silicon, Germanium, Zinc Sulphide, Zinc Selenide as well as Chalcogenide glasses.

Through the combination of high-end precision technology and intelligent software design, M³ (M Cubed) optics metrology department now offers the following measurements:

Tests

• Index of Refraction (RI)
• dn/dt (Refractive Index vs. Temperature Measurement)
• Dispersion (Refractive Index vs. Wavelength Measurement)
• Birefringence (Refractive Index Measurement of Anisotropic Materials)

All of M³ instruments are calibrated and NIST traceable. M³ are currently in process of performing validation measurements with a SRM (Standard Reference Material) from NIST."

Measurement Ranges

M³ provides refractive index measurements at wavelengths from 350nm to 14um, and temperature ranges from 77°K to +100°C (373°K).

Measurement Method

Refractive index is measured via a modified minimum deviation technique. In utilizing this technique, a small prism must be manufactured from the material under test. M³can sub-contract the prism manufacture or work with customers who wish to supply the finished prism substrate themselves.

Data

M³ can provide data in many different formats depending on your specific needs. M³can supply various types of curve fitting and dispersion algorithms (e.g. Herzberger, Schott, Sellmeier etc). Full reports can be provided in Power Point, Word, PDF, and Excel formats.

Accuracies

M³ can reach accuracies to the fourth and fifth decimal place depending on material type and sample configuration.