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Wavefront distortion is a critical factor in microscopy that can directly degrade image contrast and resolution. A wavefront represents the surface of constant phase in a light wave; while perfectly collimated beams have planar wavefronts, any interaction with non-planar surfaces or inhomogeneous media introduces deviations. These deviations, known as Wavefront Error (WFE), are measured in "waves" relative to specific reference wavelengths (typically 632.8 nm or 546.07 nm). To ensure microscopy methods succeed, WFE must be kept within strict tolerances. Using high-precision metrology, these deviations are measured and converted into actionable values to help users select dichroic beamsplitters with the appropriate flatness and Reflected Wavefront Error (RWE) for their specific application. Learn More

Fluorescence-based assays depend on detecting photons. Common to such assays is the notion of the “good” photon, which carries useful assay information, and the “bad” photon, which carries noise, background, or other information that imperils the assay. Depending on their design, optical filters can shift photons from the “bad” to the “good” category, but optimizing filter selection also requires choosing a filter with the right balance between performance and price point. That balance is explored in this tech note. Click to learn more. Learn More

The emission filter is a critical part of any fluorescence system (learn more about fluorescence filters here). Emission filters, and to a lesser extent excitation filters, provide most of the signal-to-noise ratio (SNR) enhancement in fluorescence systems. This note describes emission filters and their use in both single-point (as in photometry and point-scanning) and imaging (microscopic and macroscopic) applications. Learn More

IDEX Health & Science | Semrock has been delivering the ultimate in fluorescence filters for over 20 years. Our ultra-steep transition edges, deep blocking, and high transmissions have set the standard for excellence and have helped drive the creation of new, higher performance optical systems. In this Tech Note, you will learn to use our unique products to get the most out of your fluorescence and Raman excitation designs, no matter what the light source. Learn More

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

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 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

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

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

IDEX Health & Science makes a wide variety of 45º dichroic beamsplitters optimized for different purposes. Learn more about selecting the right dichroic beamsplitter. Learn More