FBH650-40 Premium Bandpass Filter; Dia:25 mm; CWL=650nm; FWHM=40nm

The FBH650-40 Premium Bandpass Filter is a high-quality optical component designed for precise wavelength selection, manufactured by Thorlabs. This filter is circular in shape with a diameter of 25 mm and a thickness of 2 mm, making it suitable for a wide range of optical applications.

The filter is specifically designed for a central wavelength (CWL) of 650 nm, with a full width at half maximum (FWHM) of 40 nm. This means it allows light within a 40 nm range around the central wavelength to pass through while blocking other wavelengths. This feature makes it an ideal choice for applications that require narrowband wavelength filtration, such as fluorescence microscopy, laser spectroscopy, and optical communication systems.

The FBH650-40 filter is coated on both the front and back surfaces with Thorlabs' proprietary coating (tho fbh650-40). This coating enhances the filter's performance by reducing reflection and increasing transmission, thereby improving the signal-to-noise ratio in your optical system.

The filter's physical data includes a cut-on wavelength of 630 nm and a cut-off wavelength of 670 nm. This means that it begins to transmit light at 630 nm and stops transmitting at 670 nm, effectively filtering out any wavelengths outside this range.

In terms of shape, the FBH650-40 filter has a thin lens shape, which can be beneficial in certain optical configurations. It is currently in stock and available for immediate purchase from Thorlabs' website, as indicated by its weblink status.