The variable wheel attenuator consists of 5 wheels. Four wheels contain metalized wedged silicon wafers with different attenuation levels and one wheel is empty. If necessary the empty wheel can be filled with a custom element (e.g. filter). Four attenuators have transmission 30%, 10%, 3%, and 1%. These attenuator elements can be used as a single attenuator or in combination that allows achieving different levels of attenuation.

Transmission curves (noise is smoothed) of attenuator elements are shown below. Measurements were made up to 1000 μm. However, operating wavelength range is much wider. It follows from physical mechanism of attenuator operation.

Fig. Transmission of THz attenuator elements

Transmission values of different combinations of attenuators are given in the table below.

Combination of attenuator elements	Normal value of tranmission, %
30+10	3
30+3	0.9
30+1	0.3
10+3	0.3
10+1	0.1
3+1	0.03
30+10+3	0.09
30+10+1	0.03
10+3+1	0.003
30+3+1	0.009
30+10+3+1	0.0009

Common specification:

Operating wavelenth range, μm	40 ÷ >1000
Quality of wheels in the mount, pcs.	5
Quality of attenuation grades, pcs.	4
Transmission tolerance of attenuator element, % of nomanal value	+/- 10
Damage threshold, W/cm²	several hundreds

The following THz attenuators are available from stock:

No.	Clear aperture, mm
1	25.4
2	50.8

Please check our Optics stock.
Attenuator elements can be supplied in wheel mount as well as without it.
Different clear apertures (up to 54.5 mm) attenuators are manufactured upon request.
The mount design of custom-made attenuators is discussed additionally.