Educational Materials

2023 Semrock Optical Filters Catalog

Our engineers and product management teams have collaborated to provide you with the Semrock Master Catalog from IDEX Health & Science. With proven results, we give you access to high-level engineering that will help make every photon count in your system. Learn More

Selecting Filters for Fluorescence Multiplexing

The steady advances in optical thin film deposition technology over recent decades have enabled production of high performance multiband optical filters that address the increasing demand for multicolor fluorescence instrumentation. Though there is now a wide range of available catalog filters designed for a large variety of fluorophores, selecting suitable filters is often a complex process. Here we present considerations relevant to the design of such a multiplexing system. Learn More

Maximizing the Performance of Advanced Microscopes by Controlling Wavefront Error Using Optical Filters

Any imaging instrument has a limited tolerance for wavefront error – and every optical element in the light path (including dichroic beamsplitters) contributes to wavefront error, thereby limiting overall imaging system performance. When aiming to achieve diffraction-limited imaging performance or better, it is important to consider wavefront errors from all optical elements in order to calculate the total instrument wavefront error, and to compare it to the maximum allowable value. Learn more in this white paper. Learn More

Filter Spectra at Non-normal Angles of Incidence

While most applications call for optical filters to be used at normal incidence, it is important to understand how the spectral properties of different types of filters change when using these filters a non-normal angles of incidence (AOI). There are two main effects exhibited by all filter spectrum as the angle is increased from normal which are discussed in this article. Learn More

Introduction to Fluorescence Filters

Fluorescence occurs when a molecule absorbs light at wavelengths within its absorption band, and then emits light at longer wavelengths within its emission band. For example, brightly fluorescent molecules (called fluorophores) can be attached to biologically significant molecules in e.g. cell membranes, in the brain, or even on subunits of DNA, whose structures become visible in a fluorescence microscope that allows us to track the way cells function in health and disease. Fluorescence is widely used in biology, biotechnology, and medicine, due to its extraordinary sensitivity, high specificity, and simplicity of usage. Learn more about what optical filters are included in a fluorescence instrument and how Semrock optical filters can optimize your application. Learn More

transmission graph illustrating the use of a fluorescence filter

Laser Damage Threshold

Laser damage to optical filters is strongly dependent on many factors, and thus it is difficult to guarantee the performance of a filter in all possible circumstances. Nevertheless, it is useful to identify a Laser Damage Threshold (LDT) of pulse fluence or intensity below which no damage is likely to occur. Laser damage may be broadly classified into two types: absorption-driven and dielectric-breakdown damage. Which type dominates depends on the material properties (absorption coefficient, specific heat, melting temperature, as well as defects that cause scattering and concentrated electric field effects), geometric properties of the sample (thickness, homogeneity, surface morphology, etc.), and of course the properties of the laser beam itself. Learn More