Quick answer
For 6-inch IR interferometry, choose the Zygo 6" 3.39 µm TF if you need a large-aperture reference flat optimized for 3.39 µm; opt for the Zygo 2" IR TF if you require dual-wavelength capability at 3.39 µm and 10.6 µm in a smaller, bayonet-mount form.
Wavelength matters in IR interferometry
Infrared interferometry uses wavelengths that transmit through materials opaque to visible light. 3.39 µm and 10.6 µm are common choices, each with distinct material and coating requirements. The wavelength you choose affects the optic material, surface quality specification, and the type of samples you can measure.
Aperture size and mounting trade-offs
The Zygo 6" 3.39 µm TF provides a full 6-inch clear aperture, making it suitable for testing large optics or components. In contrast, the Zygo 2" IR TF has a 2-inch aperture and a 4-inch bayonet mount, which is more compact and easier to integrate into existing setups but limits the field of view.
Trade-offs at a glance
- Aperture size: 6" TF: 6-inch clear aperture for large optics. 2" IR TF: 2-inch aperture with 4-inch bayonet mount for compact setups. Choose 6" if you need to test large components; choose 2" if space is limited.
- Wavelength flexibility: 6" TF: optimized for 3.39 µm only. 2" IR TF: works at both 3.39 µm and 10.6 µm. Pick the 2" IR TF if you need to measure at both wavelengths; stick with the 6" TF for dedicated 3.39 µm work.
- Surface quality: 6" TF: 1/20 wave PVr at 3.39 µm (~32 nm). 2" IR TF: 150 nm PVr. The 6" TF offers higher surface accuracy for demanding metrology; the 2" TF is adequate for less critical measurements.
Product facts
-
6" 3.39 um TF: The Zygo 6" 3.39 µm TF is specified at 1/20th wave PVr at 3.39 µm and made of ZnS. This high surface quality (1/20 wave) ensures accurate reference wavefronts for precision metrology of large optics at 3.39 µm.
6" 3.39 um TF
-
2" IR TF, 3.39um and 10.6um: The Zygo 2" IR TF is a dual-band transmission flat AR coated for 3.39 µm and 10.6 µm, made of ZnSe, with a 150 nm PVr surface specification. The dual-band AR coating lets you switch between two common IR wavelengths without swapping optics, though the 150 nm PVr specification is less stringent than the 1/20 wave (approx. 32 nm) on the 6" TF.
2" IR TF, 3.39um and 10.6um
Which one fits your setup?
Best for
- Users who need a large-aperture reference flat for precision 3.39 µm interferometry on 6-inch or larger optics
- Applications where the highest surface quality (1/20 wave) is critical
Not ideal for
- Users who require dual-wavelength capability (3.39 µm and 10.6 µm) in a single optic
- Compact setups where a 2-inch aperture and bayonet mount are preferred
