ATR Probe
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Tuesday, 27 March 2018

Attenuated Total Reflectance is a measurement technique used for incredibly optically dense media. For this technique, a special probe with a high refractive index must be in contact with the sample. NIR light is passed through the crystal and due to the higher refraction index, reflects off the inner surface of crystal. This results in an evanescent wave that penetrates the sample. Light is caught as it exits the crystal for analysis.

Avantes, North America now offers an ATR probe option for use with the AvaSpec-NIRLine of near-infrared instrumentsΘ. This probe is suitable for nearly any industrial process environment and operates at temperatures ranging from -30°C to 280°C and pressures up to 1200 psi. This sapphire crystal three-bounce design affords a total path length of approximately 1.5 microns and allows response down to 250 nm in samples with a refraction index up to 1.5 or choose the ATR probe option with cubic zirconia crystals for use with samples with an RI up to 1.9.

The body of the probe itself is fabricated from a PVC-coated stainless steel armor, or select the Teflon® sealant for high-temperature operation. The single crystal, lacking complex internal optical elements is a rugged option that produces a more stable, flatter baseline and linear response.

Consult with your US sales engineer to inquire about your specific requirements. Available in North America only.

Technical Specifications

Path length

3 bounce (~1.5 microns)

Also available: 1 Bounce

ATR material

Sapphire (250 nm- 2200 nm)

Cubic Zirconia (380- 2200 nm)

Maximum Sample Refractive Index

Sapphire 1.5

Cubic Zirconia 1.9

Quantum Efficiency

Typical: 20% at 500* nm

Guaranteed: 15% at 500 nm

Optical Fiber Type

UV or NIR 2 by 6 around- 1 200/220

Silica on silica

Fiber Packaging

Armored 14-fiber bundle

Jacketing: PVC (to 80°C) or Teflon® (to 300°C)

Fiber Length

3m standard**

Fiber Termination

SMA 905



Body & Extension Materials

316 SS ɸ

Body Dimensions

1.75”L  x  0.5”OD

Extension Tube dimensions

4”L x 0.05”OD

Seal Type


Seal Material

Kalrez®6375 or 4079

Temperature Range

-30°C to 280°C

Maximum Pressure

1200 psi/ 83 bar


Θ Available in North America only

* Efficiency measured relative to direct fiber connection between light source and detector using a 400 micron-core fiber

** Other fiber lengths available upon request

ɸ Other materials available on request- allow 8 weeks for delivery of custom materials