Glass Bandpass Filters
Glass bandpass filters only transmit light within a narrow wavelength range, as shown in the figure. Their spectral characteristics consist of the maximum transmissivity (TM), the wavelength of the peak (lM), front-cut-off wavelength, the rear cut-off wavelength, and the half-peak width.
The wavelengths corresponding to the half of the maximum transmissivity are l2 and l1, and the half-peak width is determined by l2 – l1. The front (or rear) cut-off wavelength corresponds to the wavelength of “zero” transmissivity. However, in some cases, the transmissivity of the rear cut-off wavelength may not reach zero. In such instances, it is determined by the transmissivity at a certain wavelength. Bandpass filter glass is designated as DTB, with the peak wavelength used as its serial number.
Spectrum Characteristic Curve of Band-Pass Filter Glass
Technical Indexes
Type | Maximum Transmissivity | Front Cut-off | Behind Cut-off | Half-peak Width | Thickness (nm) |
DTB400 | >45/400+/-2 | 0/320+/-5 | 0/525+/-5 | <90 | 2 |
DTB435 | >48/435+/-2 | 0/340+/-5 | <2.0/540+/-5 | <100 | 4 |
DTB470 | >40/470+/-2 | 0/340+/-5 | 0/600+/-5 | <115 | 4 |
DTB500 | >48/500+/-2 | 0/380+/-5 | 0/630+/-5 | <100 | 4 |
DTB530 | >48/530+/-2 | 0/420+/-5 | 0/670+/-5 | <95 | 2 |
DTB545 | >48/545+/-2 | 0/400+/-5 | 0/720+/-5 | <100 | 4 |
DTB560 | >40/560+/-2 | 0/435+/-5 | 0/725+/-5 | <104 | 4 |
DTB600 | >36/600+/-2 | 0/470+/-5 | <1.0/800+/-5 | <95 | 4 |
DTB660 | >44/660+/-2 | 0/500+/-5 | <2.0/800+/-5 | <115 | 4 |
DTB700 | >28/700+/-2 | <0.5/570+/-5 | <2.0/820+/-5 | <95 | 4 |
DTB720 | >50/720+/-2 | 0/500+/-5 | <9.0/900+/-5 | <140 | 4 |
DTB740 | >25/740+/-2 | 0/650+/-5 | <4.0/900+/-5 | <85 | 4 |
Reliable Glass Bandpass Filters with Custom Options
Glass bandpass filters are durable, cost-effective solutions with high transmissions at selected wavelengths, making them ideal for applications where light angles vary. They are stable and widely used in agriculture, medical analysis, and fluorescence applications. While interference filters offer more bandpass options, they come at a higher cost. Avantier offers optical bandpass filters, available in circular and square sizes, ranging from UV to near-infrared, covering key laser and biomedical lines. All filters come mounted for protection and include free spectral data. Please contact us for more details or to request a quotation.
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