275nm Optical UV Interference Filter FWHM 10nm 80% Transmission Overview

The 275nm Optical UV Interference Filter (FWHM 10nm, 80% transmission) is designed for use with 275nm peak deep-UV LEDs and certain mercury lamp sources. It delivers a peak transmission exceeding 80% within a Full Width at Half Maximum (FWHM) of just 10 nm, while achieving an optical density (OD) of 4 for out-of-band blocking across the 200–330 nm range. Utilizing a fused silica substrate (available in 1.0 mm or 0.7 mm thicknesses) and durable hard-ion-assisted coating technology, the filter features a high laser damage threshold and low autofluorescence. It is suitable for applications such as UVC disinfection monitoring, UV absorption detection of biomolecules, spectroscopic analysis, and water quality sensing.

275nm Optical UV Interference Filter FWHM 10nm 80% Transmission

 

275nm Optical UV Interference Filter FWHM 10nm 80% Transmission Technical Specifcation

• Centerwavelength: 275+/-2nm
• FWHM: 10+/-2nm
• Transmission Peak >80%
• Blocking depth: 200-330@OD4  330-400nm@OD3 average
• Standard Size in stock: D12.7*6mm D25.4*6mm

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Customization Capability of UV Optical Filters

275nm Optical UV Interference Filter FWHM 10nm 80% Transmission Applications

UVC-LED Disinfection Equipment

275 nm is the dominant peak wavelength for UVC-LEDs used in water purifiers, air disinfectors, and surface sterilization devices. Although LEDs have a narrow emission spectrum, a faint “long-wave tail” extending beyond 300 nm persists. A 275/10 nm UV interference filter efficiently transmits the LED emission peak (with >80% transmittance) while achieving OD4+ blocking of stray UV light (200–280 nm), the long-wave tail (>300 nm), and visible light, thereby ensuring effective disinfection.

Online Water Quality Analyzers

Nitrate in water exhibits a characteristic absorption peak near 275 nm, and this wavelength often serves as a reference for monitoring COD or total organic matter. A 275/10 nm UV filter transmits the 275 nm wavelength while eliminating non-linear errors caused by the absorption and scattering of stray light at other wavelengths, resulting in more accurate nitrate and COD measurements.

Fluorescence Detection

Natural fluorescent probes, such as tryptophan, have optimal excitation peaks near 280 nm; narrow-band light at 275 nm provides efficient excitation. A 275/10 nm bandpass filter allows only a narrow band of UV light (275 nm ±5 nm) to illuminate the sample, exciting substances like tryptophan and tyrosine to emit fluorescence in the 300–400 nm range.