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:
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.
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.
