Fluorescence Filters are critical components used in biomedical and life science instruments. Their prior function is to separate and select the characteristic spectral bands of excitation and emitted fluorescence of the tested substance in biomedical fluorescence analysis instruments. These filters find widespread applications in fields such as Point-of-Care Testing (POCT), Polymerase Chain Reaction (PCR), fluorescence enzyme labeling instruments, and fluorescence microscopes. Fluorescence filters consist of two to three parts: excitation filters, emission filters (also known as barrier filers), and, depending on the optical path requirements, dichroic filters might be employed. 

During the operation process, the excitation filter is placed within the illumination path of a fluorescence microscope and transmits a narrow band of light around the peak fluorophore excitation wavelength (i.e. the wavelengths that excite a specific dye) toward the specimen. The emission filter (also known as the barrier filter) selects the fluorescence emitted from the sample while removing other unwanted traces of excited light. Barrier filters block (suppress) shorter wavelengths and have high transmission for longer wavelengths. Emission filters can be either bandpass filters or long-pass filters, depending on the specific requirements of the application. A dichroic filter (or beamsplitter) is placed at a 45° angle in the microscope's optical path. It reflects one color of light (excitation light) and transmits another color of light (emission light).  In a microscope, the dichroic mirror directs the proper wavelengths to the specimen and to the image plane. Ideal dichroic filters and beamsplitters have sharp transitions between maximum reflection and maximum transmission, with a >95% reflection for the bandwidth of the excitation filter and a transmission of >90% for the bandwidth of the emission filter.

North Optics offers a large selection of fluorescence filters, the fluorescence filters are crafted with standardized dimensions compatible with filter cubes produced by elite suppliers for convenient installation. Our fluorescence filters can support miscellaneous common fluorophores such as FAM EX, Alexa Fluor, ATTO, BCECF, Cy5, Cy3, DAPI, DyLight, GFP, FITC, LysoTracker, mCherry, MitoTracker, Qdot, Quasar, Rhodamine, Texas Red, etc. North Optics’s fluorescence filters consist of dielectric coatings deposited on glass substrates, through the meticulous engineering of varied refractive indices and reflection characteristics of the filter, high transmission within the transmission band and exceptional optical densities greater than OD6 are obtained, providing effective spectral selection strength. These filters are designed to pass or reject wavelengths of light with great selection performance. High-precision polishing and processing are implemented in our state-of-the-art production line to ensure optimized spectral separation. 

The following table shows the suggested fluorescence filter combinations used for some common fluorescent fluorophores, if you have requirements or need more detail please contact us:

Specifications:

Excitation Filter:

Emission Filter: