Standard filters

Our standard filters are produced in quantity (and used in our standard detector systems) and we are able to offer these at a better price than non-standard filters.

Band-pass

Our standard band-pass filters have the following properties (other filter designs are available on request):

Centre wavelength
(microns)
Centre frequency
(Thz)
Centre frequency
(cm-1)
Bandwidth
(FWHM)
850
0.35 11.7 10%
450 0.67 22.2 14%
215 1.4 46.5 19%
155 1.9 64.5 22%

The measured transmission spectra are shown below:

 

Measured transmission spectra of standard band-pass filters

 

Low-pass

Our standard low-pass filters have the following properties (other designs are available on request):

Cut-off frequency
(cm-1)
Cut-off frequency
(THz)
Cut-off wavelength
(microns)
10
0.3 1000
20 0.6 500
33 1 300
66 2 150
100 3 100
200 6 50
300 9 30
600 18 17

The performance is demonstrated below using the measured transmission spectrum of our 9 THz design. The graph below shows that the average in-band transmission efficiency is 85% or better.

 

Measured in-band transmission spectrum of a standard 9 THz low-pass filter

Out-of-band blocking is better than 0.1% over a very wide range of frequencies out to the optical region, as shown in the graph below.

 

Measured wide-band transmission for a 9 THz low-pass filter