Products Description
BP393.3nm Bandpass Filter | FWHM 3nm, T>90%, OD2 200-3000nm
BP393.3nm passes 393.3 nm at over 90% and holds OD2 rejection from 200 to 3000 nm in a single element. The 3 nm FWHM is the point of the part: near-UV lines sit a few nanometres away, and a filter sold only as UV transmitting hands all of them to the detector.
Technical Specifications
| Parameter | Specification | Note |
|---|---|---|
| Centre wavelength | 393.3 nm ± 1 nm | Normal incidence |
| FWHM | 3 nm ± 1 nm | 2–4 nm worst case |
| Peak transmission | > 90% at CWL | Coated part |
| Blocking | OD > 2, 200–3000 nm | 1% maximum out of band |
| Angle of incidence | 0deg; nominal | Tilt shifts CWL shorter |
| Format | Round, square, custom outline | Mounted or unmounted |
The tolerances stack: a delivered part can sit 1 nm off centre with a 2–4 nm passband, so a design that assumes an exact edge wavelength has to carry that budget. A 3 nm filter also cannot be tilted — the passband moves shorter off normal, and a few degrees is a measurable share of the bandwidth.
Applications
Near-UV line isolation ahead of a PMT, CCD or photodiode; narrow excitation channels in UV-Vis and fluorescence spectroscopy; builds where a 393 nm channel runs beside visible ones without cross-talk. Matching dichroic and emission elements come as a set — see fluorescence filters.
Customization and Supply
Round and square are standard; rectangular, elliptical and other outlines are cut to drawing, rings sized to the holder. CWL, bandwidth, blocking depth and thickness are set per project, and standard wavelengths ship from stock. Catalogue range: bandpass filters; off-catalogue work runs as a custom optical filter.
Talk to an Optical Engineer
When a 393.3 nm channel underperforms — low signal, rising background, a passband that drifts as the holder warms — send the specification, the source and the layout. We will check the tolerance stack and the mounting angle. sales@optofilters.com
Tags: custom bandpass 3nm FWHM OD2 blocking 393.3nm bandpass filter UV narrowband
