Fluorescence Microscope Parts

All 11 parts on the diagram

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The filter cube 4

Excitation filter It lets through only the light that makes the specimen glow.
Dichroic mirror (beamsplitter) It reflects the excitation light down and lets the emitted light pass.
Emission filter (barrier filter) It stops leftover excitation light and passes the emitted light.
Filter cube (filter block) It holds a matched set of two filters and the dichroic mirror.

Lamp, lenses and light 7

Light source (arc lamp) It makes the bright light that lights the specimen.
Objective lens It focuses the light on the specimen and collects the glow.
Specimen The thing being viewed. Its fluorescent parts glow when lit.
Eyepiece You look through it to see the glowing specimen.
Camera It records the image of the glowing specimen.
Excitation light Light of the color that the fluorescent dye absorbs.
Emitted light (fluorescence) The glow given off by the specimen. It is much weaker than the excitation light.

How this list was compiled: Every name checked on 2026-10-02 and kept only where at least two of these use it. (1) Wikipedia, Fluorescence microscope, https://en.wikipedia.org/wiki/Fluorescence_microscope : light source (xenon arc lamp, mercury-vapor lamp, LEDs), excitation filter, dichroic mirror or dichroic beamsplitter, emission filter, the objective that both lights the specimen and collects the fluorescence, specimen, eyepiece or detector, the filter cube turret above the objective lenses, digital camera, excitation light, emitted light. (2) Florida State University, Molecular Expressions Microscopy Primer, Anatomy of the Fluorescence Microscope, https://micro.magnet.fsu.edu/primer/techniques/fluorescence/anatomy/fluoromicroanatomy.html : the arc lamp in its lamphouse, excitation filter, dichromatic beamsplitter (also termed dichroic mirror), emission or barrier filter, objective, specimen, eyepieces, camera, the optical blocks (filter blocks) that hold a matched excitation and emission filter set and a dichromatic beamsplitter, excitation light, fluorescence emission. (3) A review article, Fluorescence Microscopy, Cold Spring Harbor Protocols, 2014, read in the US National Library of Medicine's archive, https://pmc.ncbi.nlm.nih.gov/articles/PMC4711767/ : the filter cube that has an excitation filter, a dichroic mirror tilted 45 degrees and a barrier or emission filter, the objective lens, the specimen, the camera, excitation light, emitted light. Filter cube and emitted light are the names of (1) and (3); the university page writes filter block and fluorescence emission. Labels, hints, detail lines and position notes were written for this site. Licence: own work

The drawing: Drawn for this site on 2026-10-02 from plain geometry; nothing traced. Licence: own work

How it works

The fluorescence microscope parts are named here on one cut-through drawing: the light source, the excitation filter, the dichroic mirror, the emission filter, the objective lens, the eyepiece and the camera. Tap a part to read what it does.

Read the full guide

Down to the specimen

The excitation filter passes only the light that the fluorescent dye absorbs. The dichroic mirror turns that light down, and the objective lens focuses it on the specimen.

Back up to the eye

The lit dye gives off light of a longer wavelength, so it has a different color. The same objective lens collects it. It passes straight through the dichroic mirror and the emission filter, which stops leftover excitation light, and reaches the eyepiece or the camera.

A turret above the objective lenses holds several filter cubes, each with its own matched set of filters.

Questions and answers

What are the parts of a fluorescence microscope?

A light source, an excitation filter, a dichroic mirror and an emission filter, which sit together in a filter cube, plus the objective lens, the specimen, and an eyepiece or a camera to see the image.

What are the fluorescence microscope parts and functions?

The light source lights the specimen. The excitation filter picks the color the dye absorbs. The dichroic mirror reflects that light down and lets the glow pass up. The emission filter blocks leftover excitation light. The objective lens focuses and collects the light.

What does the dichroic mirror do in a fluorescence microscope?

It works as a filter that depends on wavelength. It reflects the excitation light toward the specimen and lets the fluorescence, which has a longer wavelength, pass through to the eyepiece or the detector.

What is the difference between the excitation filter and the emission filter?

The excitation filter sits between the lamp and the specimen and chooses the light that makes the dye glow. The emission filter, also called the barrier filter, sits between the specimen and the eye and passes only the glow.

Why does the light go through the objective lens twice?

In most fluorescence microscopes the specimen is lit and viewed through the same objective lens. Most of the excitation light passes on through the specimen, so little of it comes back with the much weaker glow.