400nm Bandpass Filter

400nm light lies in the violet end of the visible spectrum, adjacent to the ultraviolet (UV) range, characterized by relatively high energy and a wavelength that is critical for exciting specific fluorescent dyes and interacting with certain biological or chemical materials.

  • Application 1: In fluorescence microscopy, the filter isolates 400nm light to selectively excite violet-emitting fluorescent probes, enabling clear visualization of labeled cellular structures while blocking unwanted background light.
  • Application 2: In spectroscopy, it is employed to extract 400nm light for precise absorbance or reflectance measurements of samples that exhibit strong spectral responses at this wavelength, such as certain organic compounds or colorants.
  • Application 3: In optical sensing and analytical instruments, the filter ensures only 400nm light reaches the detector, enhancing the accuracy of measurements in applications like water quality monitoring, where specific contaminants or dissolved substances absorb or emit strongly at this wavelength.
400nm Bandpass Filter
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Filters

5 items
Center Wavelength (nm)
FWHM (nm)
Optical Density(OD)

Filter

Center Wavelength (nm)
FWHM (nm)
Optical Density(OD)
US9563101B2 - Common-path noncollinear optical parametric amplifier

US9563101B2 - Common-path noncollinear optical parametric amplifier

Context: A common-path non-collinear optical parametric amplifier (NOPA) system used for generating ultrashort laser pulses.

Usage of Filter: A 400nm bandpass filter (specifically with a ~40nm bandwidth) is placed in the optical path of the pump beam, after the second harmonic generation stage and before the amplification crystal.

Function: It acts as a spectral cleaner, transmitting the generated 400nm pump light (second harmonic of the 800nm source) while blocking the residual 800nm fundamental light and other unwanted spectral components.

Result: Provides a clean, high-contrast pump beam for the parametric amplification process, enhancing the efficiency and stability of the amplified signal.

US10274807B2 - Optical quantification of interfacial charge states

US10274807B2 - Optical quantification of interfacial charge states

Context: An optical system for quantifying the electric charge density at the interface of a material (e.g., a membrane or particle) using Second Harmonic Generation (SHG) spectroscopy.

Usage of Filter: A 400nm bandpass filter is positioned in the detection path, in front of the photomultiplier tube (PMT) or detector.

Function: It selectively isolates the Second Harmonic Generation signal (which is at 400nm when the sample is excited by an 800nm laser) while rigorously blocking the intense reflected fundamental 800nm light.

Result: Allows for the precise detection of the weak SHG signal generated at the interface, which is directly correlated to the interfacial potential and charge density.

US20180299367A1 - Method and apparatus for analyzing a fluid

US20180299367A1 - Method and apparatus for analyzing a fluid

Context: A portable fluid analysis apparatus designed to measure optical properties (like fluorescence or absorbance) of a fluid sample, often for medical or environmental testing.

Usage of Filter: A bandpass filter centered at or including the 400nm region (e.g., 400-425nm range) is located in the detection channel after light has passed through or interacted with the fluid sample.

Function: It filters the light emerging from the sample to ensure that only the specific wavelength band of interest (e.g., a fluorescence emission or specific absorption band around 400nm) reaches the sensor.

Result: Maximizes the signal-to-noise ratio for the target analyte, ensuring accurate quantification of the fluid's properties even in the presence of ambient light or other spectral noise.

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