Check out my other itemsThorlabs FB1550-12 Near Infrared Bandpass Interference Filter Diameter: 1 Inch Bandpass FWHM: 11 nm Central Wavelength: 1550 nm General Features of Thorlabs Bandpass Filters
The bandpass and laser line filters shown on this page feature center wavelengths of 700 nm to 1650 nm. Transmission and optical density curves for individual filters are available by clicking on the blue info icon for each individual filter below. Each filter is mounted in a black anodized aluminum ring with an outer diameter of Ø1/2" or Ø1" and a maximum edge thickness of 6.3 mm. Please note that Ø1/2" filter options are highlighted in green in the tables below. Thorlabs' bandpass filters provide one of the simplest ways to transmit a well-defined wavelength band of light, while rejecting other unwanted radiation. Their design is essentially that of a thin film Fabry-Perot Interferometer formed by vacuum deposition techniques and consists of two reflecting stacks, separated by an even-order spacer layer. These reflecting stacks are constructed from alternating layers of high and low refractive index materials, which can have a reflectance in excess of 99.99%. By varying the thickness of the spacer layer and/or the number of reflecting layers, the central wavelength and bandwidth of the filter can be altered. Because of the Fabry-Perot design, these filters are designed for use at a 0° angle of incidence (AOI). The transmission band will be shifted in wavelength and may be reduced when used with other AOIs. For more details on the properties and construction of our bandpass filters, please see the Tutorial tab. These types of filters display very high transmission in the bandpass region, but the spectral range of blocked light on either side of the bandpass region is narrow. To compensate for this, an additional blocking component is added, which is either an all dielectric or a metal-dielectric depending on the requirements of the filter. Although this additional blocking component will eliminate any unwanted out-of-band radiation, it also reduces the filters' overall transmission throughput. Each filter is housed in a black anodized aluminum ring that is labeled with an arrow indicating the design propagation direction. The ring makes handling easier and enhances the blocking OD by limiting scattering. These filters can be mounted in our extensive line of filter mounts and wheels. As the mounts are not threaded, retaining rings will be required to mount the filters in one of our internally-threaded lens tubes. We do not recommend removing the filter from its mount, as the filter consists of several layers of glass that are held together with epoxy and the mounting ring. These glass layers are necessary to protect the dielectric coating from the atmosphere; exposure would significantly reduce the filter's transmission efficiency over time. |