Shortwave pass optical thin film filters are a variety of edge filters: optical thin film filters that split the waveband into two component regions of specified wavelengths.
One waveband is transmitted, while the other is rejected (i.e. reflected) and can be used as a secondary signal in its own right.
The name of ‘shortwave pass’ optical filters is an indication that the transmitted waveband is in the shorter wavelength spectrum, while the longer wavelengths are reflected.
Shortwave pass edge filters are defined by the transition wavelength (the wavelength at which the transmitted signal drops to 50% of full intensity).
The characteristics of short pass filters can also include the width of the transmission and reflection bands, and the steepness of the transition edge (the cut-off between the two).
In general, desirable characteristics of short pass optical filters include:
Envin Scientific can produce bespoke short pass edge filters that offer high transmission and reflection, using sophisticated manufacturing techniques to ensure a clean transition edge.
Thin film filters are produced using a vacuum deposition process to layer dielectric coatings on to a substrate.
Our bespoke short pass edge filters are constructed using many layers, which ensures low ripple, steep transition edges and high maximum transmission.
We offer a wide variety of formats of short pass filters, suitable for transmitting wavelengths between 300nm and 8,000nm.
The choice of substrate (e.g. glass, organic or semiconductor) can also influence the optical properties of the finished filter, allowing us to add further to the overall capabilities of the product and meet even more complex client needs.
We rigorously test the performance of our bespoke shortwave pass optical filters to ensure they offer the characteristics required to transmit a strong signal with minimal noise.
In order to do this we have several industry-standard spectrophotometers:
Every test is recorded in detail, including the machine run, process log and measurements, and added to an electronic archive that can be retrieved whenever necessary to verify the performance of the short pass filter.
If you would like to know more about our shortwave pass optical thin film filters or short pass dichroic filters, please get in touch and our team will be happy to help.
We welcome orders and enquiries relating to bespoke thin film filters, and can advise on what can be achieved and any physical limitations on the size and thickness of the finished filter.
Equally if you need to know about any of our substrate options, just ask. We have sheet, moulded, fire-polished, ground-polished and diamond-turned substrates available as windows, mirrors, curved lenses, prisms and aspheric surfaces.