Description

The filter with cutoff region on both sides of the transmission band of the spectral characteristic curve is called a bandpass filter. Bandpass filter is an important optical thin film element, which has been widely used in chemistry, spectroscopy, laser, astrophysics, optical fiber communication, biology and other fields. The spectral curve of the band-pass filter prepared by the principle of light wave interference, the spectral transmission region near the wavelength is called the passband of the filter, usually on both sides of the cut-off region, and there may be a by-pass band around the cut-off region, usually need to use colored glass, absorption film or cut-off filter to eliminate the by-pass band.

Bandpass filters are roughly divided into broad band filters and narrow band filters according to spectral characteristics, two kinds of filters are usually combined, the application of light wave interference principle to prepare bandpass filters, and bandpass filters have been widely used in various fields.

· Broad Band Filter

Description

A filter for separating a wide band of monochromatic light from composite light. The filter has a passband half-width Δλ≥0.01λ0, where λ0 is the central wavelength of the filter transmittance curve.

· Narrow Band Filter

Description

Narrow band filter is subdivided from the bandpass filter, its definition is the same as the bandpass filter, that is, the filter allows the light signal to pass in a specific band, and the light signal is blocked on both sides outside this band, the passband of the narrowband filter is relatively narrow, generally less than 5% of the central wavelength value.

Products

· NBP505 narrow-band filter

Product characteristics

NBP505 narrow-band filter is mainly used to selectively reflect (or attenuate) optical elements of other wavelengths of light through the light wave near the central wavelength of 505nm. It adopts multi-layer hard film by high vacuum evaporation of ion-assisted deposition nanomaterials. The film layer has good density and high imaging clarity. By plating hard film design, the filter has a long service life, accurate wavelength positioning, using ion evaporation technology, the filter has a small performance drift and penetration when the temperature changes, and high cutoff depth, which can effectively reduce the interference of non-target wavelength.

Optical index

CWL：515±7nm

Transmittance：T=60%

FWHM：7nm

Cut-off band：400nm-480nm/530nm-1100nm 

Blocked：T<0.1%

Application

· Fluorescence microscopic imaging

· ColorMeasurement

· Industrial inspection

· Laser technology

· NBP532 narrow-band filter

Product characteristics

532nm filter is one of the filter bands used in many optical solutions, 532nm narrowband filter in laser applications emit light mainly green laser, while some laser solutions will also choose 532nm filter as a second harmonic processing filter.

Optical index

CWL：532±2nm

Peak Transmittance：T＞90%

FWHM：10nm

Cut-off band：200nm-1100nm 

Optical  Density：>OD3-OD6 UV-NIR

Application

· Atmospheric Particle Detection

· Microplate Reader

· Infrared Medical Instrument

· Fluorescence Analyzer

· NBP850 narrow-band filter

Product characteristics

The NBP850 narrowband filter is an infrared bandpass filter developed for the near-infrared 850nm band, because the band is widely used in a variety of biometric detection applications, it can also be called a biometric filter, which allows light near the near-infrared 850nm wavelength to pass, while blocking other bands outside this range of light. Because the 850nm wavelength is located in the near infrared region, NBP850 narrow-band filter is particularly prominent in the application, and has the characteristics of strong penetration and not easy to be absorbed by water, so NBP850 narrow-band filter has a wide range of applications in many fields.

Optical index

CWL：850nm

Peak Transmittance：T>58%

FWHM：23nm

Cut-off band：350nm-830nm T<0.01%/870nm-1100nm T<0.1%

Application

· Infrared Imaging

· Biometric Identification (face recognition, iris recognition)

· Medical Instruments And Imaging

· Optical Communication And Laser Technology

· NBP940 narrow-band filter

Product characteristics

The 940nm infrared ink recognition filter is suitable for working under strong light (sunlight) interference and has a transmittance of up to 80%, and the instrument light attenuation coefficient is small, which can effectively improve the working distance and light intensity.

Optical index

CWL：940±2nm

Peak Transmittance：T>90%

FWHM：20nm

Cut-off band：200nm~870nm，990nm~1100nm

Blocked：T<0.1%

Application

· Infrared Ink Recognition

· Infrared Medical Instrument

· Laser Rangefinder

· Mobile Phone Bar Code Scanner