The 1225nm narrowband filter is a precision optical component designed based on the principle of optical interference. By alternately depositing multiple layers of high/low refractive index films (such as TiO? and SiO?) on the substrate surface, it achieves high transmittance (typically >90%) for light at the 1225nm center wavelength and efficient blocking of other wavelength bands (blocking rate generally <0.1%). Its typical full width at half maximum (FWHM) is usually controlled within **±5nm to ±20nm** and can be customized according to application requirements, ensuring that only light of the target wavelength passes through while effectively suppressing background stray light interference. It is suitable for optical systems requiring precise wavelength selection.

Material and Process Characteristics of the 1225nm Narrowband Filter

• Substrate Selection: Commonly used optical-grade glass (such as BK7, B270, JGS1, etc.) with high transmittance (>90%), good chemical stability, and mechanical strength, adaptable for use under various environmental conditions.
• Coating Technology: Utilizes high-precision ion sputtering coating processes. By precisely controlling film thickness and the number of layers, it ensures accuracy of the center wavelength (tolerance typically ±1nm) and stability of spectral performance. The coating exhibits strong adhesion and good wear resistance, extending the filter's service life.
• Performance Parameters: In addition to core parameters such as center wavelength, FWHM, and blocking rate, attention must also be paid to surface finish (typically 40-20), thickness tolerance (±0.1mm), and other indicators to meet the assembly and usage requirements of different optical systems.
• Spectral Analysis and Detection: Used in near-infrared spectroscopy instruments to select specific 1225nm wavelength light for material composition analysis, such as detecting characteristic absorption peaks of certain organic compounds or gas molecules.
• Optical Communication: Potentially applied in wavelength division multiplexing (WDM) technology in fiber optic communication systems. By isolating 1225nm wavelength light signals, it enhances communication capacity and signal transmission stability.
• Environmental Monitoring: Can be used in environmental monitoring equipment to detect absorption or scattering characteristics of specific pollutants in the atmosphere or water at the 1225nm wavelength, enabling accurate measurement of pollutant concentrations.
• Laser Systems: Used in conjunction with 1225nm wavelength lasers in systems such as laser ranging and lidar. It filters out stray light generated by the laser, ensuring laser signal purity and system measurement accuracy.
• Research and Medical Applications: In biomedical research, it can be used for near-infrared fluorescence imaging or phototherapy equipment to select specific wavelengths for exciting fluorescence signals in biological tissues or for photobiomodulation.