High‑performance Linear Variable Filter Sets built on decades of optical innovation, enabling you to create advanced optical tunable systems with the best possible performance.
Linear Variable Filter Sets
Combining wide tuning ranges, high transmission in passbands, and deep out-of-band blocking into a single Linear Variable Filter can be incredibly complex. In many cases, a far more effective approach is to build advanced functionality using a small number of highly performing filters – a filter set.
By combining a Linear Variable Long-Wave Pass (LVLWP) filter and a Linear Variable Short-Wave Pass (LVSWP) filter, you can construct a fully tunable bandpass filter set. Moving these two edge filters independently allows for precise, real-time adjustments of both the center wavelength and bandwidth over a wide spectral range. If your application demands enhanced signal isolation, homogeneous out-of-band blocking filters can be seamlessly integrated into the series.
For EPI-Fluorescence applications, our Variable Edge Filters are often combined with a Continuously Variable Dichroic. If an extended blocking range is required, this can be achieved by inserting Homogeneous Blocking Filters in the light path at certain wavelengths.
Our filter sets contain either Exponentially Variable Dichroic (EV Dichroic) or Linear Variable Dichroic (LV Dichroic) as well as CVLWP + CVSWP tunable bandpass sets.
Example of Tunable Bandpass Filter Sets
By combining our Continuously Variable Long Wave Pass filters (CVLWPs) with our Continuously Variable Short Wave Pass filters (CVSWPs) it is possible to create a tunable Bandpass Filter where both the bandwidth and centre wavelength are tunable.
The tunable filter works by sliding the two filters parallel to the long edge of the filter substrates.
When the two filters are slid relative to each other the bandpass is tuned and when the two filters are slid equal distance to the right or left the center wavelength is tuned.
Continuously Variable Filter sets product specifications
Below you can explore a selection of products we have manufactured. Some are available from stock, while others are made to order.
We work closely with our customers to design customized filters tailored to the specific needs of each application.
Tunable Bandpass Filter Sets
| Centre wavelength tuning range (nm) | Minimum bandwidth (nm) | Maximum bandwidth (nm) | Out-of-band blocking (SW) | Out-of-band blocking (LW) | Max size | Data sheets |
|---|---|---|---|---|---|---|
| 659 - 886 | 13 - 18 | 94 - 119 | OD4 | OD4 | 82.4 mm x 26.5 mm x 0.9 mm |  |
| 415 - 645 | 8 - 13 | 70 - 156 | OD4 | OD4 | 82.4 mm x 28.5 mm x 0.9 mm | |
| 380 - 800 | 8 - 16 | 79 - 120 | OD4 | OD4 | 88 mm x 11 mm x 2 mm | |
| 389 - 990 | 10 | 75 | OD4 | OD4 | 110 mm x 17 mm x 2 mm | |
| 324 - 841 | 6.4 - 17 | 20 - 100 | OD2.7 | OD4 | 60 mm x 15 mm x 3 mm | |
Tunable filters for EPI-fluorescence
| Dichroic wavelength range (nm) | Center wavelength tuning range (nm) | Minimum bandwidth (nm) | Maximum bandwidth (nm) | Out-of-band blocking | Max size | Data sheets |
|---|---|---|---|---|---|---|
| 360 - 860 | 380 - 800 | 8 - 16 | 79 - 120 | OD5.4 | 110 mm x 17 mm x 2 | |
| 320 - 760 | 324 - 841 | 6.4 - 17 | 20 - 100 | OD5.4 | 60 mm x 23 mm x 1 mm | |
Product example: Continuously Variable filter set for the range 385 nm to 1000 nm
This filter set consist of 6 filter, a continuously variable long wave pass filters, a continuously variable short wave pass filters and 4 homogeneous blocking filters for various wavelength regions.
CVLWP 383-1000 (LF104550) can be combined with CVSWP 386-1005 (LF104555) to make a continuously variable bandpass filter for the range 385 nm to
1000 nm.
Filter set specifications
- Wavelength center tuning range: 389 – 990 nm
- Bandwidth tuning range: 10 nm to 75 nm
- Minimum out-of-band blocking: OD4
T
Typical applications of Linear Variable Filter Sets
Wavelength scanner/mono-chomator
When combined with a broadband light source, a a set of CVSWP and CVLWP filters can be used to create a tunable filter. This allows the selection of center wavelength and bandwidth by translating the filter along the long edge of the substrate.
Read how to create tunable filters using linear variable filters in our tech note here.
EPI-fluorescence
For EPI-Fluorescence applications, our Variable Edge Filters are often combined with a Continuously Variable Dichroic. If an extended blocking range is required, this can be achieved by inserting Homogeneous Blocking Filters in the light path at certain wavelengths. Read more about linear variable filter sets for epi-fluorescence here..
Frequently asked questions about Linear Variable Dichroics
When should I consider using a Linear Variable Filter Set?
Linear Variable Filter Sets are commonly used for advanced applications where a wide tuning range combined with high optical performance is required.
Can Delta Optical Thin Film customize a Linear Variable Filter Set for my application?
Yes, we actually prefer to engage in a dialogue with our customers to find the best solution to an optical filtering problem.
Does the variation in edge wavelength have to be linear?
No. The gradient is often close to linear but, we can design other types of gradients - exponential for example.