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Fluorescence filters are a type of optical filter that is used to selectively transmit or reflect light within a specific wavelength range to enhance or suppress the fluorescence signal generated by the sample.

Fluorescence filters have a wide range of applications in fields such as biomedicine, biochemistry, materials science, and environmental monitoring. Let’s take a closer look at how fluorescence filters work, their structure, and their applications.

Advantages of Fluorescence Filters

Fluorescence Filters

Fluorescence filters usually provide the following benefits:

  1. Fluorescence filters precisely and selectively transmit specific wavelengths of excitation light or fluorescence signals, thereby improving signal-to-background contrast.
  2. By effectively filtering out light at non-target wavelengths, fluorescence filters can reduce background noise and enhance the detection sensitivity of fluorescence signals.
  3. Fluorescence filters usually have high transmittance and narrow bandpass width, ensuring that only light within the target wavelength range can pass through, improving signal accuracy and stability.
  4. The fluorescence filter has a simple structure, is easy to install and adjust, is suitable for various optical systems and experimental conditions, and improves the efficiency and repeatability of experiments.

Fluorescence Filters Working Principle

Fluorescence filters take advantage of the principle that a sample absorbs excitation light at a specific wavelength and emits a fluorescence signal at another wavelength.

Typically, the excitation light wavelength is shorter than the fluorescence signal wavelength. Fluorescence filters contain two key parts:

Excitation filter An excitation filter selectively transmits the wavelength of excitation light used to excite the sample and blocks or reflects light of other wavelengths.

Emission filter: The emission filter selectively transmits the fluorescence signal wavelength emitted by the sample and blocks or reflects the excitation light and other wavelengths of light.

Through the combination of these two filters, the excitation light can be transmitted to the sample to the greatest extent, and only the fluorescence signal from the sample can pass through the detection system.

After briefly understanding some basic working principles of excitation filters and emission filters, let’s explore the structures of fluorescence filters together?

Fluorescence Filters Structure

The structure of fluorescence filters can be divided into two types:

Single-channel filter: A single-channel filter contains an excitation filter and an emission filter to select specific excitation and emission wavelengths. This type of filter is suitable for the detection of single fluorescent dyes.

Multichannel Filters: Multichannel filters contain multiple excitation and/or emission filters, allowing the selection of multiple excitation and/or emission wavelengths. This type of filter is suitable for detection of multiple fluorescent labels or complex fluorescent signals.

Application of Fluorescence Filters

Fluorescence Filters

Fluorescence Filters are often used in multiple application fields due to their special functions, usually including the following:

Biomedical Research

Cell and tissue imaging: Fluorescence microscopy is commonly used to observe and analyze structure and function in living cells and tissues. Fluorescently labeled biomolecules (such as proteins, nucleic acids, organelles, etc.) can be selectively excited and detected through fluorescence filters.

Protein localization and expression: Fluorescent protein labeling technology (such as GFP, RFP, etc.) combined with fluorescence filters can be used to track and observe the localization and expression level of specific proteins in cells or tissues.

Cell activity monitoring: By using specific fluorescent probes and fluorescence filters, changes in bioactive substances (such as Ca2+, ROS, etc.) within cells can be monitored in real-time to study cell activities and signal transduction processes.

Drug Discovery and Biochemical Analysis

Fluorescein analysis: Fluorescein derivatives are widely used in fluorescence detection to determine the molecular concentration, activity, and interactions in biological samples.

Enzyme reaction detection: Fluorescent substrates and fluorescent probes combined with fluorescence filters can be used to detect enzyme activity, screen inhibitors, and other biochemical experiments.

Immunofluorescence analysis: used to detect the binding between specific antigens and antibodies, often used in immunological research and diagnostics.

Environmental Monitoring

Water quality monitoring: Fluorescent probes combined with fluorescence filters can be used to detect the concentration and distribution of pollutants (such as heavy metal ions, organic pollutants, etc.) in water.

Air quality monitoring: Fluorescent probes and fluorescence filters can be used to detect the concentration and distribution of harmful gases (such as NO2, SO2, etc.) in the air.

Material Science

Research on photoelectric properties: By combining fluorescent labels or fluorescent probes with fluorescent filters, the photoelectric properties, optical response, and other characteristics of materials can be studied.

Surface fluorescence: Fluorescence filters can be used to detect fluorescence signals on the surface of materials to study the structure and properties of the material surface.

The wide application of fluorescence filters has made them an indispensable tool in the fields of scientific research, medical diagnosis, and environmental monitoring, providing important technical support for us to understand life, protect the environment, and develop new materials.


Learn the key definitions and uses of fluorescence filters, which play a key role in fields such as biomedicine, biochemistry, environmental monitoring, and materials science.

By selectively transmitting or reflecting light of specific wavelengths, they enable us to effectively excite and detect the fluorescence signal of the sample, thereby achieving various research and application purposes.

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Frequently Asked Questions

How do fluorescent filter cubes work?

The function of the fluorescence filter cube is to selectively transmit the excitation light to the sample through the excitation filter, and then reflect it to the emission plate by the dichroic mirror. The remaining light matches the fluorescent dye (fluorophore) on the sample to observe the sample. Accurate target.

This selective filtering process enhances the contrast and specificity of fluorescent signals in the microscope, enabling precise visualization and analysis of fluorescently labeled samples.

What is the wavelength of a fluorescence filter?

Fluorescence filters typically operate in the ultraviolet (UV) to near-infrared (NIR) wavelength range of light. Excitation filters typically cover the range from approximately 300 nanometers (nm) to 700 nm, while emission filters typically cover the range from 400 nm to 800 nm.

However, the exact wavelength range may vary depending on the specific filter design and fluorophore used in the experiment.

Related reading: What is dichroic mirror

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