OP-7894 Solid Zinc Selenide Etalons

AMS item number: SW11170

Zinc Selenide; 0.6-20 µm; Finesse ~1.6, Dependent on Wavelength; FSR Dependent on Wavelength;... more

Product information "OP-7894 Solid Zinc Selenide Etalons"

Zinc Selenide; 0.6-20 µm; Finesse ~1.6, Dependent on Wavelength; FSR Dependent on Wavelength; Thickness 0.5, 1.0, 2.0 mm; Uncoated; Dia. 12.7 mm; Clear Aperture Dia. 8 mm

LightMachinery’s OP-7894 series of solid Zinc Selenide (ZnSe) etalons are very wide wavelength range, low-finesse etalons components with a reasonably high index (~2.5 depending on wavelength) that creates a reasonably high finesse without any coatings. Zinc Selenide etalons also remain transmissive over a very broad wavelength range from 600 nm to 20 µm. Thermal tuning is high but not as rapid as Silicon or Germanium.

Unfortunately Zinc Selenide is one of the few optical materials that cannot be fluid jet polished (due to the grain structure), so LightMachinery cannot make the parallelism super uniform and coat the ZnSe devices to create high-finesse etalons. But for low-finesse (~1.6) etalons that work over a massive wavelength range, the OP-7894 devices – available with a diameter of 12.7 mm and 0.5, 1.0 or 2.0 mm thickness – are pretty handy.

Etalons are optically transparent, flat components with very precisely parallel reflecting surfaces. For high performance (i.e. resolution), these components require very high-quality, flat and level surfaces with low roughness and extreme parallelism. Solid Zinc Selenide etalons are comparatively simple, robust, yet very parallel optical components with a wide variety of applications in lasers and spectroscopy.

Although solid etalons are generally coated to increase the finesse of the etalon, uncoated solid etalons like this series – using only the 4% fresnel reflection to provide the etalon effect – are often used inside laser cavities since only low finesse is required to filter out unwanted laser wavelengths, and uncoated etalons are very damage resistant.

One major issue with solid etalons is their instability to temperature changes (both the index and the physical thickness of the etalon material change with temperature), which can be unacceptable in certain applications. In those cases, please refer to air spaced etalons that reduce this problem of temperature dependence by using air as the etalon medium. In certain applications though, the temperature dependence can also be a useful method for tuning the transmission peak position since it effectively changes the thickness of the etalon.

Sometimes you need something special – if you are looking for a customized solid ZnSe etalon that exactly meets your specific requirements, please get in touch with the AMS Technologies etalon experts. Our supplier LightMachinery is extremely experienced with specifying, designing and manufacturing custom etalons. We are looking forward to discussing your customized etalon solution!

Key Features:

Etalon Material: Zinc Selenide (ZnSe)
Wavelength Range: 0.6 to 20 µm (Red to LR)
Finesse: ~1.6, Dependent on Wavelength
Free Spectral Range, FSR: Dependent on Wavelength
Uncoated
Diameter: 12.7 mm (1/2")
Thickness: 0.5, 1.0, 2.0 mm
Clear Aperture: Diameter 8 mm
Surface Figure: λ/50
Transmitted Wavefront Error: λ/8
Surface Quality: 40/20 or Better
Wedge: <2.5 arcsec

Applications: Lasers; Spectroscopy; Interferometers; Wavelength Measurement; Fine-structural Investigation of Spectral Lines