|Materials||BK7 or UV Fused Silica||Size||customized|
|Optical Density at Rejection Wavelength||OD4 or OD6||High Transmission at Transmission Wavelength Range||>90% or customized|
|Aperture||>90%||Transmitted Wavefront Distortion||λ/4@633nm or λ/10@ 633nm|
|Parallelism||<30 arc second||Surface Quality||40/20 S/D|
An Optical Notch Filter is also known as a Band Stop filter or Band Reject Filter which transmit most wavelength with little intensity loss and attenuate light within a wavelength band to a very low level. The light is rejected/blocked in a specific wavelength range named the stop band wavelength range, while passing above and below this band. In fact, they can be viewed as an inverse of a band pass filter.
There are several important key specifications needed to be take into consideration when selecting notched filters of your requirements: stop band wavelength (i.e the wavelength range at which signals will be interrupted), power handling capability (i.e. the maximum power magnitude tolerable for the filter), and the most important factor, optical density (OD, a numerical value corresponding with the transmission percentage of a media ), which determines the rejection levels of Notched filters. To be more precise, the formulated relationship between OD and T% is OD=log10 1/T where where OD is optical density and T is absolute transmittance.
Hangzhou Shalom EO offers notched filters with lower transmission at rejected wavelength ranges from OD4 to OD6, and high transmission of minimum 90% at the transmitting wavelength range (transmission rate could be even greater than 90% available upon custom requests ). Material options include BK7 or Ultra-Violet (UV) fused silica, with customized sizes available. The filters we supplied are properly fitting for laser line applications with particular wavelengths of 405nm, 488nm, 514nm, 533nm, 561nm, 594nm, 633nm, 658nm, 785nm,808nm, 980nm and 1064 nm.
Curve Samples of Notched Filters: