Educational Materials

Find Your Optical Filters Guide

Unsure if catalog, custom, or hybrid optical filters are right for your project? Explore our step-by-step guide to find the best Semrock optical filter for your application. Learn More

Finding Your Filters - explore our step-by-step guide

Sputtered Thin-film Coatings

Optical thin-film coatings can be deposited by a variety of methods. Traditionally the most popular methods for depositing multilayer coatings – required for higher-performance mirrors and filters – include thermal and electron-beam (e-beam) evaporation and ion-assisted e-beam evaporation (IAD). Learn more in this tech note. Learn More

Working with Optical Density

Optical Density – or OD, as it is commonly called – is a convenient tool to describe the transmission of light through a highly blocking optical filter (when the transmission is extremely small). Learn More

Notch Filters

Notch filters are ideal for applications that require nearly complete rejection of a laser line while passing as much non-laser light as possible. The main drawback of standard thin-film notch filters has been a limited passband range due to the fundamental and higher-harmonic spectral stop bands. Learn More

RazorEdge and MaxLine are a Perfect Match

The Semrock MaxLine and RazorEdge U-grade optical filters make an ideal filter pair for applications like Raman spectroscopy – they fit together like hand-in-glove. Learn More

Measurement of Optical Filter Spectra

Due to limitations of standard metrology techniques, the measured spectral characteristics of thin-film interference filters are frequently not determined accurately, especially when there are steep and deep edges. Learn more about IDEX Health & Science | Semrock's solution to measure optical filter spectra. Learn More