The long pass filter allows light with wavelengths greater than a specific value to pass through while blocking light with wavelengths shorter than this value. The working principle of this type of filter is based on optical interference and diffraction. It is typically composed of multiple thin film layers, whose thickness and refractive index are carefully designed to produce constructive or destructive interference within a specific wavelength range.
Long pass filters have excellent characteristics such as high transmittance, extremely low loss, high stability, and low thermal expansion coefficient. These features make them widely applicable in various fields, including optics, electronics, and biomedical fields. For example, in fluorescence microscopy imaging, long pass filters can be used to block excitation light, allowing only the fluorescence signal to pass through, thereby improving the contrast and clarity of the image.
The application areas of long pass filters are very broad, including spectral analysis, laser technology, biomedical imaging, optical communication, environmental monitoring, and remote sensing. In spectral analysis, long pass filters are used to separate and detect light of specific wavelengths; in laser technology, they are used to optimize the quality and stability of laser beams; in biomedical imaging, they help researchers more accurately identify and analyze fluorescent markers in cells or tissues.
English
русский
