Excitation and emission filters are marked with an arrow that shows the recommended direction of light propagation.
Dichroic filters are marked on the side with the dichroic coating. Light should be incident on this side for best performance.
Features
Excitation, Emission, and Dichroic Filters for Fluorescence Imaging
>90% Transmission over Desired Wavelength Band
Sharp Cutoff (T < 0.001%) Outside the Transmission Band
Matched Filter Sets Designed to Target Many Common Fluorophores (See Fluorophores Tab for Alternate Fluorophore Compatibility)
- BFP - CFP - WGFP - GFP
- FITC - Alexa Fluor® 488 - YFP - tdTomato
- TRITC - Texas Red - mCherry - Cyanine (CY3.5)
Excitation and Emission Filters are Mounted in Black-Anodized Housings
Dichroic Filters are Unmounted
Filter Sets are Available at a Savings Over Individual Filter Prices
These excitation, emission, and dichroic filters are designed specifically for use in fluorescence imaging applications. They are fabricated at industry-standard dimensions that make them compatible with filter cubes from all major manufacturers. We offer individual filters and filter sets targeted at common fluorophores: BFP, CFP, WGFP, GFP, FITC, Alexa Fluor® 488, YFP, tdTomato, TRITC, Texas Red, mCherry, and Cyanine (CY3.5). In addition, the Fluorophores tab provides information on the alternative fluorophores suitable for these filters. These filters are also available pre-installed into our microscope filter cubes
Filter Design Our filters are manufactured to high-performance optical specifications and designed for durability. They are produced via multiple dielectric layers deposited on a high-precision, fused silica substrate. The substrate is ground and polished to ensure that the highest possible image quality is maintained. The resulting hard-coated optics consist of filter layers that are denser than those obtained from electron beam deposition techniques, and which reduce water absorption while greatly enhancing durability, stability, and performance of the filter. Each filter layer is monitored during growth to ensure minimal deviation from design specification thickness, ensuring overall high-quality filter performance.
Each filter is housed in a black anodized aluminum ring which makes handling easier and enhances the blocking OD by limiting scattering. These filters can be mounted in our extensive line of filter mounts and wheels. As the mounts are not threaded, Ø1" retaining rings will be required to mount the filters in one of our internally-threaded SM1 lens tubes. For customers who wish to use these filters in Thorlabs, Olympus, or Nikon fluorescence microscopes, Thorlabs manufactures a family of Drop-In Microscope Filter Cubes.
Specification
Excitation Filters
Emission Filters
Dichroic Filters
MDF-GFP2, MDF-TOM, MDF-MCHC, & MDF-MCHA Kits
All Other Excitation Filters
MDF-GFP2, MDF-TOM, MDF-MCHC, & MDF-MCHA Kits
All Other Excitation Filters
Dichroics in MDF-GFP2, MDF-MCHA, MDF-MCHC, & MDF-TOM Kits
All Other Dichroics
Size
Ø25 +0.0/-0.1 mm
Ø25 ± 0.1 mm
Ø25 +0.0/-0.1 mm
Ø25 ± 0.1 mm
25.2 mm x 35.6 mm
25.0 mm x 36.0 mm
Clear Aperture
>Ø21 mm
>Ø22 mm
>Ø21 mm
80% of Area
>(22.5 mm x 32.4 mm)
Angle of Incidence
0° ± 5°
45° ± 1.5°
Thickness
5.0 ± 0.1 mm
3.5 ± 0.1 mm
1.05 ± 0.05 mm
1.0 ± 0.1 mm
Surface Quality
60-40 Scratch-Dig
Substrate
Fused Silica
Item #
Kit Item #
Fluorophore
Filter Type
Center Wavelength
FWHM
Reflection Band
Transmission Band
AR Coatinga
Transmission Datab
MF390-18
MDF-BFP
BFP
Excitation
390 nm
18 nm
-
-
-
MF460-60
Emission
460 nm
60 nm
-
-
-
MD416
Dichroic
-
-
Ravg > 90% 360 - 407 nm
Tabs > 90% 425 - 575 nm
Rabs < 2% from 400 to 800 nm
MF434-17
MDF-CFP
CFP
Excitation
434 nm
17 nm
-
-
-
MF479-40
Emission
479 nm
40 nm
-
-
-
MD453
Dichroic
-
-
Ravg > 90% 423 - 445 nm
Tabs > 90% 460 - 610 nm
Rabs < 2% from 400 to 800 nm
MF445-45
MDF-WGFP
WGFP
Excitation
445 nm
45 nm
-
-
-
MF510-42
Emission
510 nm
42 nm
-
-
-
MD480
Dichroic
-
-
Ravg > 90% 415 - 470 nm
Tabs > 90% 490 - 720 nm
Rabs < 2% from 400 - 800 nm
MF469-35
MDF-GFP
GFP
Excitation
469 nm
35 nm
-
-
-
MF525-39
Emission
525 nm
39 nm
-
-
-
MD498
Dichroic
-
-
Ravg > 90% 452 - 490 nm
Tabs > 90% 505 - 800 nm
Rabs < 2% from 400 to 800 nm
MF475-35
MDF-FITC
FITC
Excitation
475 nm
35 nm
-
-
-
MF530-43
Emission
530 nm
43 nm
-
-
-
MD499
Dichroic
-
-
Ravg > 90% 470 - 490 nm
Tabs > 90% 508 - 675 nm
Rabs < 2% from 400 to 800 nm
-
MDF-GFP2
GFP Alexa Fluor® 488
Excitation
482 nm
18 nm
-
-
-
-
Emission
520 nm
28 nm
-
-
-
-
Dichroic
-
-
Ravg > 93% 350 - 488 nm
Tavg > 93% 502 - 950 nm
-
MF497-16
MDF-YFP
YFP
Excitation
497 nm
16 nm
-
-
-
MF535-22
Emission
535 nm
22 nm
-
-
-
MD515
Dichroic
-
-
Ravg > 90% 490 - 510 nm
Tabs > 90% 525 - 700 nm
-
-
MDF-TOM
tdTomato
Excitation
531 nm
40 nm
-
-
-
-
Emission
593 nm
40 nm
-
-
-
-
Dichroic
-
-
Ravg > 98% 350 - 555 nm
Tavg > 93% 569 - 950 nm
-
MF542-20
MDF-TRITC
TRITC
Excitation
542 nm
20 nm
-
-
-
MF620-52c
Emission
620 nm
52 nm
-
-
-
MD568
Dichroic
-
-
Ravg > 90% 525 - 556 nm
Tabs > 90% 580 - 650 nm
Rabs < 2% from 400 to 800 nm
MF559-34
MDF-TXRED
TXRED
Excitation
559 nm
34 nm
-
-
-
MF630-69
Emission
630 nm
69 nm
-
-
-
MD588d
Dichroic
-
-
Ravg > 90% 533 - 580 nm
Tabs > 90% 595 - 800 nm
Rabs < 2% from 400 to 800 nm
-
MDF-MCHC
mCherry
Excitation
562 nm
40 nm
-
-
-
-
Emission
641 nm
75 nm
-
-
-
-
Dichroic
-
-
Ravg > 98% 350 - 585 nm
Tavg > 93% 601 - 950 nm
-
MF565-24
MDF-CY3.5
CY3.5
Excitation
565 nm
24 nm
-
-
-
MF620-52c
Emission
620 nm
52 nm
-
-
-
MD588d
Dichroic
-
-
Ravg > 90% 533 - 580 nm
Tabs > 90% 595 - 800 nm
Rabs < 2% from 400 to 800 nm
-
MDF-MCHA
mCherry
Excitation
578 nm
21 nm
-
-
-
-
Emission
641 nm
75 nm
-
-
-
-
Dichroic
-
-
Ravg > 98% 350 - 588 nm
Tavg > 93% 603 - 950 nm
-
Select dichroics have an AR coating designed for 45° AOI on the back surface.
Click on for a plot and downloadable data.
Designed to work with both TRITC and CY3.5.
Designed to work with both CY3.5 and TXRED.
Click to Enlarge Schematic of light passing through a fluorescence microscope.
MDF-YFP filter set transmission graph. Note the dichroic mirror (green) reflects light in the excitation wavelength range (blue), and transmits light in the emission wavelength range (green).
Filters for Fluorescence Microscopy
Fluorophores A fluorophore is a molecule or portion of a molecule that is capable of producing fluorescence. When light of the appropriate frequency necessary to excite a molecule from its ground state to an excited state is present, excitation will occur. However, once in an excited state, the molecule will be unstable. After some short period of time (typically 10-15 to 10-9 s), a photon will be released, thereby enabling the molecule to return to a lower energy state. The emitted radiation will be at a longer wavelength (lower energy) than the absorbed radiation due to the loss of energy through various mechanisms such as vibrations, sound, and thermal energy.
A single fluorophore can be continually excited unless it is destroyed by photobleaching (i.e. the nonreversible destruction of a fluorophore due to photon-induced chemical damage or covalent modification). The average number of excitation and emission cycles that a particular fluorophore can undergo prior to photobleaching depends on its molecular structure and the local environment; some fluorophores bleach quickly after emitting only a few photons while others are far more robust and can undergo thousands or even millions of cycles before bleaching occurs.
Filters for Fluorescence Microscopy The experimental setup to the right shows the typical filters used for epi-fluorescence microscopy, a form of microscopy in which both the excitation and emission light travel through the microscope objective. By carefully choosing the appropriate filters and mirrors for a given application, the signal-to-noise ratio can be maximized. As shown in the schematic to the right, three types of filters are used to maximize the fluorescence signal while minimizing the unwanted radiation. Each optical element is discussed below.
Excitation Filter The excitation filter only allows a narrow band of wavelengths to pass through it, around the peak fluorophore excitation wavelength. For example, as shown in the graph to the right, the bandpass region corresponding to greater than 90% transmission for the Yellow Fluorescent Protein (YFP) Excitation Filter (MF497-16) is 489 - 505 nm; incident radiation outside of this range is either partially (for regions near the transmission region) or totally (for regions further from the bandpass region) blocked by the filter.
Dichroic Mirror Dichroic mirrors are designed to reflect light whose wavelength is below a specific value (i.e. the cutoff wavelength) while permitting all other wavelengths to pass through it unaltered. In a microscope, the dichroic mirror directs the proper wavelength range to the sample as well as to the image plane. The cutoff wavelength value associated with each mirror indicates the wavelength that corresponds to 50% transmission. For example, as shown in the graph to the right, the cutoff wavelength for the Yellow Fluorescent Protein (YFP) Dichroic Mirror (MD515) is ~515 nm. The Specs tab provides information on the reflectance and transmission for each type of dichroic mirror.
By placing one of these mirrors into the experimental setup at 45° with respect to the incident radiation, the excitation radiation (shown in blue in the above right schematic) is reflected off of the surface of the dichroic mirror and directed towards the sample and microscope objective, while the fluorescence emanating from the sample (shown in red in the above right schematic) passes through the mirror to the detection system.
Although dichroic mirrors play a crucial role in fluorescence microscopy, they are not perfect when it comes to blocking unwanted light; typically, ~90% of the light at wavelengths below the cutoff wavelength value are reflected and ~90% of the light at wavelengths above this value are transmitted by the dichroic mirror. Hence, some of the excitation light can be transmitted through the dichroic mirror along with the longer wavelength fluorescence emitted by the sample. To prevent this unwanted light from reaching the detection system, an emission filter is used in addition to the dichroic mirror.
Emission Filter An emission filter serves the purpose of allowing the desirable fluorescence from the sample to reach the detector while blocking unwanted traces of excitation light. Like the excitation filter, this filter only allows a narrow band of wavelengths to pass through it, around the peak fluorophore emission wavelength. For example, as shown in the graph to the right, the bandpass region corresponding to greater than 90% transmission for the Yellow Fluorescent Protein (YFP) Emission Filter (MF535-22) is 524 - 546 nm; incident radiation outside of this range is either partially (for regions near the transmission region) or totally (for regions further from the bandpass region) blocked by the filter.
Keya
Acceptable - Actual performance depends on individual experimental conditions.
Compatible - Ideal, or nearly ideal, performance under most experimental conditions.
Optimized - Optimal performance under all experimental conditions.
a. Absorption and emission spectra are unavailable if any is red.
The table below displays all of the fluorophores that are compatible with our filter sets. The filter set item numbers are listed across the top row and the fluorophores are listed down the first column. Scroll through the table to view fluorophore compatibility with our filter sets.
Click on the below to view the filter set transmission with the absorption and emission spectra of the fluorophore. The key to the right details the meaning of all check marks in the table below. Please note that absorption and emission spectra are unavailable if any is red.
If I had the option to get a 2"/50mm filter set for FITC fluorescent imaging I would...
nbayconich
 (posted 2020-03-05 01:03:35.0)
Thank you for your feedback, I will log your request in our internal engineering forum for future reference. We can provide custom sized filters upon request, I will reach out to you directly to discuss our custom capabilities.
tcohen
 (posted 2012-09-13 11:44:00.0)
Response from Tim at Thorlabs: Thank you for your interest in our custom capabilities. We should be able to provide this as a special and I have contacted you to go over your requirements.
densta
 (posted 2012-09-13 12:33:11.0)
Dear Madam/Sir
I want to perform some preliminary fluorescence tests for a project of ours.
I am interested in buying one of the following emission filters
MF525-39: GFP
MF530-43: FITC
I noticed from your records that the outer diameter of the filter is 25 mm.
In our system we need a filter with outer diameter 17 mm. The filter could be bare glass without an outer support ring. Is it possible to have one of the above mentioned filters in this form? What would be the cost?
Best regards,
Dimosthenis Stamopoulos
bdada
 (posted 2012-02-24 17:13:00.0)
Response from Buki at Thorlabs to
Thank you for your interest in our imaging dichroic filters.
Testing has shown no signs of degradation when exposed to at least 6 W of power from an unfiltered xenon arc lamp over a 25 mm diameter (corresponding to 1.2 W/cm2) for over 500 hours.
Please contact TechSupport@thorlabs.com if you have any questions.
user
 (posted 2012-02-10 13:05:04.0)
Can you please provide laser damage threshold ratings for the dichroic filters?
jjurado
 (posted 2011-03-22 16:05:00.0)
Response from Javier at Thorlabs to flickingerd: Thank you for your feedback. Our filters follow that same convention as that of Semrock's. The arrow points to the recommended direction of light propagation. The reason for this is although the filter will function with either side facing the source, it is recommended to place the coated side toward the source. This will minimize any thermal effects or possible thermal damage that blocking intense out-of-band radiation might cause due to absorption by the substrate or colored glass filter layers.
lmorgus
 (posted 2011-03-21 18:23:00.0)
A response from Laurie at Thorlabs to flickingerd: As a follow-up to the response you received earlier today from Javier in our technical support group, I wanted to also reach out to you to thank you for your feedback. We have updated our web presentation to provide information about what the arrow on these optic mounts indicates. As a further step, we have made a list of other web pages on our site that need some attention for similar reasons. In the coming days, we will be updating those pages to clarify our engravings so that our customers can efficiently find the information they need to use our products effectively. Again, thank you for taking the time to drop us a note with a suggestion for improvement.
flickingerd
 (posted 2011-03-21 14:29:07.0)
I couldnt find info on proper filter orientation. There are arrows on the filters, but Ive seen different conventions on what these mean (Chroma says point arrow towards specimen for emission filters, yet Semrock convention is always point arrow in direction of light propagation, I think). How about your filters? This should be in "Tutorial" section, Id think. Please contact me with proper orientation rules. (Although Im still not sure exactly why this matters...I guess I can think of some minor reasons...)
apalmentieri
 (posted 2010-02-18 09:42:22.0)
A response from Adam at Thorlabs to pludowise: I believe we should be able to offer this item as a custom option. I would like to contact you directly to get more information about your application, the quantity necessary, and the exact size of the optic.
pludowise
 (posted 2010-02-18 00:01:38.0)
I am interested in finding a dichroic filter similar to MDF-TXRED, but shifted to loger wavelengths. Specifically, I need a dichroic for a Cy5 dye, which needs to transmit at 640 nm, and reflect at 690 nm. I also need this in a 1 mm thickness mounted at 45 deg AOI. Thank you.
These excitation fluorescence imaging filters are specifically designed to be used in microscopy and imaging applications. Each Ø25 mm filter is mounted in a 5 mm thick black anodized housing. The housing has an arrow engraved on it that points in the recommended light propagation direction.
These filters provide excellent transmission of the desired excitation wavelength (>90%), with a sharp spectral cutoff and low transmission at other wavelengths (<0.001%). Click on the icons above to view product-specific transmission data. For additional fluorophore compatability, please see the Fluorophores tab.
These emission fluorescence imaging filters are specifically designed to be used in microscopy and imaging applications. Each Ø25 mm filter is mounted in a 3.5 mm thick black anodized housing. The housing has an arrow engraved on it that points in the recommended light propagation direction.
These filters provide excellent transmission of the desired emission wavelength (>90%), with a sharp spectral cutoff and low transmission at other wavelengths (<0.001%). Click on the icons above to view product-specific transmission data. For additional fluorophore compatability, please see the Fluorophores tab.
Thorlabs' Dichroic Filters are designed to separate light of different wavelengths. When light is incident on the filter at a 45° angle with respect to the normal, the excitation light and its associated back reflection are reflected while the longer wavelength fluorescence signal is transmitted. These filters are unmounted, but are marked by a dash to indicate the coated side of the filter, which light should be incident on. Each filter is 25.0 mm x 36.0 mm. If your application would benefit from a round, mounted dichroic filter, consider our round Dichroic Filters. Click on the icons above to view product-specific transmission data. For further fluorophore compatability, please see the Fluorophores tab.
Since standard fluorescence imaging applications generally incorporate three different filters (i.e., one excitation, one emission, and one dichroic filter) to maximize the signal-to-noise ratio, Thorlabs offers these filters as a set at a savings over purchasing them separately.
Please Note: The excitation and emission filter housings have an arrow engraved on them that points in the recommended direction of light propagation. Dichroic filters have a marking on the side with the beamsplitter coating. Light should be incident on the marked side of the optic for optimal performance. For further fluorophore compatability, please see the Fluorophores tab.
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Additional Fluorescence Filters and Dichroic Mirrors