Multimesh filters
Our multi-mesh filters provide unrivalled transmission and blocking performance at terahertz wavelengths. Each of our filters is hand made for the customer, and is guaranteed to have an exceptionally sharp cut on and cut off, and a precise centre frequency.
The filters can be built to any shape or size in the diameter range 2 - 300 mm, and can be built to operate in both ambient and cryogenic environments. Larger diameters are available as a special order, please contact us for details.
We can provide high-pass, low-pass, band-pass and notch filters as standard, and non-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.
We are also able to provide mounting options for our filters. Our standard mounts are circular SS rings with apertures ranging from 6-85mm which we recommend for cryogenic usage. However, we are capable of machining any size/shape mount required.
Standard Bandpass Filters
Our standard band-pass filters are shown in the table (above) and graphs (below). The top graph shows the linear transmission spectra for each filter, whereas in the bottom graph a log scale is shown of a single band-pass filter, to show the out of band blocking. We keep these filters always in stock, and can be shipped on a faster timescale than non-standard filters providing they are < 200 mm OD.
Standard Low-pass filters
The performance of our low-pass filters can be viewed by clicking the icons on the left of the table above. Below is a measured example 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.
Non standard filters
We can design and build tailored filters in low-pass, high-pass, band-pass and band-stop (notch) forms, with a particular profile to suit your specific application:
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The edge frequency can be specified
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The filter can be optimised to give the maximum transmission of particular frequencies within the pass-band i.e. the interference fringes seen below the edge on the standard low pass filters can be positioned to best suit your transmission and rejection requirements
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The out-of-band blocking level can be tuned to reduce undesirable frequencies.
Please contact us with your requirements.
A non-standard composite solar filter designed and built by QMC Instruments for the ALMA telescope in Atacama Chile.
