A 400nm optical bandpass filter with a Full Width at Half Maximum (FWHM) of 40nm permits light within a specific range of wavelengths centered around 400nm to pass through efficiently. The FWHM value of 40nm indicates that the filter has moderate spectral resolution, allowing transmission of light within approximately a 40nm range around the central wavelength of 400nm.

These types of filters find applications in various fields such as fluorescence microscopy, flow cytometry, and optical sensing, where precise control over specific wavelengths of light is necessary for analysis or detection purposes. Additionally, they can be used in UV light sources, spectroscopy, and photolithography.

Coligh’s stock standard 400nm optical bandpass filter feature:

• Feature: UV bandpass filter
• Center wavelength：400±10nm
• Angle of incidence: 0°
• FWHM: 40nm±10nm
• Blocking range: 200-1100nm
• Blocking depth: OD4, OD5, OD6, OD8
• Transmission average: Above 90%
• Thickness：1.0mm, 1.1mm
• Size: φ8mm, φ10mm, φ12.5mm, φ25.4mm, φ50mm mounted or unmounted
• Other stock filters bandwidth reference: 10nm, 12nm, 20nm, 25nm

Custom option:

• Bandwidth: any other bandwith client request
• Angle of incidence: Depend on request
• Blocking depth: Deep less than OD8
• Size: round or square smaller than 150*150mm
• Material thickness: Depend on request
• Transmission and blocking rang: custom as per requirement or between 200nm to 1500nm