CI Systems CVF - Circular Variable Filters
CVF - Circular Variable Filters
- Full wavelength scanning from visible to long wave IR
- Successive discrete wavelength selection in the range of the segment
- Allows instrument design flexibility and versatility
- High volume manufacturing
CI Systems’ Circular Variable Filters (CVF’s) are interference narrow-pass filters of advanced design which are deposited on circular substrates, called segments. Film thickness, and therefore the wavelength of peak transmittance varies linearly and continuously with angular position on the segment. CI Systems CVF’s are ideally suited as monochromators in compact, non-dispersive spectrometers, providing medium-resolution spectral radiation measurements, or when information is desired at a number of specific wavelengths in the relevant spectral range.
A CVF can be manufactured in any wavelength range from 0.4μm in the visible region of the spectrum up to 14.3 μm in the infrared. The specific wavelength at which the radiation is transmitted by the segment is selected by appropriately positioning it on the optical beam. A CVF segment rotation, in a way that the beam traces a circumferential path on it, provides a continuous scan of its complete wavelength range. A spectral resolution element size on the CVF varies between one and two millimeters.
CI Systems’ CVF’s are physically durable and withstand the rigors of industrial and field environment conditions. They are resistant to abrasion and humidity, and can be cleaned by conventional optical cleaning techniques.Applications engineering support and optical assembly capabilities are available to assist you with the calibration and integration of CVF in your system.
| Segment No. | Value in | 5a | 5b | 6 | 1 | 2 | 3 | 4 |
| Nominal wavelength range | μm | 0.4 - 0.675 | 0.65 - 0.95 | 0.9 - 1.35 | 1.3 - 2.5 | 2.4 - 4.6 | 4.3 - 8.1 | 7.7 - 14.3 |
| Blocking range | μm | 0.3 - 1.15 | 0.3 - 1.15 | 0.3 - 2.6 | 1 - 5 | 1 - 7 | 1 - 15 | 1 - 15 |
| Bandwidth (FWHM) * | % | 1.5 | 1.5 | 1.5 | 2.0 | 1.8 | 1.5 | 1.8 |
| Transmittance at peak wavelength | % | >50% | >50% | >50% | >25% | >25% | >60% | >30% |
| Out-of-band average transmittance** | % | <0.1% | <0.1% | <0.1% | <0.1% | <0.1% | <0.1% | <0.1% |
* as a %of peak wavelength, typical
** in the blocking range
CI Systems CVF - Circular Variable Filters Specifications 
