01
Bandpass Filters
A bandpass filter is a filter that transmits a specific spectral band (passband) and rejects wavelengths outside this band (off-band or the blocking area).
Ferroperm Optics offer custom specified bandpass filters with exceptionally good blocking for photometric measurements within the biomedical field. The peak transmittance at different wavelengths in a filter set can either be high, have a standard transmittance or be completely matched to comply with the sensitivity of the optical system of the customer.
Ferroperm Optics offer a comprehensive range of standard filters for photometric applications in the spectral area of 280 nm to 1100 nm. The nominal bandwidth is typically 8 nm or 10 nm.
02
Fluorescence Filter Sets
Fluorescence measurements require a pair of filters carefully matched to the absorption and emission spectra of the fluorescent colour compound to be analysed.
When defining this excitation/emission filter pair, the two main parameters are: First, the overlap of the excitation spectrum and excitation filter, which defines the signal level. Second, the crossing point of the excitation and emission filter curves, together with the stop-band quality, defines the signal-to-noise ratio. A dichroic beam splitter is often added between the filter pair to further increase the signal-to-noise ratio.
Ferroperm Optics offer custom specified fluorescence filter sets in the wavelength range of 280 to 900 nm with bandwidths from 5 nm to 200 nm. A comprehensive stock of filters for the most common fluorochromes is available.
03
Dichroic Beamsplitters
Ferroperm Optics offer a range of standard beam splitters. These beam splitters are often used in multi-wavelength channel biomedical analyzers and offer a competitive and simple way for our customers to reduce the size and the mechanical complexity of the optical module. The main purpose is to separate or select one wavelength channel from the rest by reflection at 45° AOI. The basic version is coated on high-quality float glass (with a thickness of 1.1 mm) using our own plasma-assisted hard coating technology that provides good batch uniformity and very low coating stress. Even without an AR-coating the beam splitters have a transmission of more than 87% and a reflection higher than 95% at the wavelength selected. The size is customizable, but we stock a standard size of 11×11 mm². This size works well with our large selection of 6×6 mm² or diameter 10 mm bandpass filters and allows a compact optical module with excellent performance.
04
Edge Filters
Optical edge filters are key components in optical systems, designed to selectively transmit or block light at specific wavelengths or ranges. By precisely controlling the transition between transmission and blocking, these filters enhance image contrast and suppress unwanted spectral components. Widely used in applications such as fluorescence microscopy, spectroscopy, and telecommunications, optical edge filters offer high transmission rates, sharp cutoffs, and minimal spectral distortion. Their versatility and reliability make them indispensable tools for researchers and engineers in various fields of optics and photonics.
05
Neutral-density filters and other metal coatings
A neutral-density (ND) filter is used to uniformly attenuate the intensity of light over a broad spectral range. Either absorption or a combination of absorption and reflection can accomplish attenuation. These carefully prepared filters find wide applications for precise attenuation of light. For example, beams can be attenuated to levels where photometers are most accurate and linear, extending their useful range. Calibration of optical equipment is another widely used application and neutral density filters for this purpose can be delivered with a NIST traceable measurement certificate if required.
Optical Density (OD) is the term most used to characterise a neutral density filter and OD is defined as the base 10 logarithm of the reciprocal of transmittance (T)
Ferroperm Optics offer neutral density filters with OD values ranging from 0.1 to 6 OD. Common OD values are typically in stock.
