This fluorescence filter set, manufactured by Coligh, is specifically optimized for the Alexa Fluor 405 dye and includes an excitation filter, an emission filter, and a dichroic mirror.

The excitation filter is 395/25 nm, precisely matching the excitation peak of Alexa Fluor 405 and providing high-purity excitation light (±12.5 nm) to maximize excitation efficiency.
The emission filter is 431/28 nm, accurately capturing the dye’s characteristic emission peak (425–439 nm) while effectively eliminating background stray light.
The dichroic mirror is 411 nm, efficiently separating excitation and emission paths with transmission/reflection rates over 95%, ensuring zero signal crosstalk.
Within the passband, the excitation filter offers >80% transmission, and the emission filter offers >90% transmission, significantly enhancing the detection of weak fluorescence signals—especially suitable for low-abundance sample imaging.
Outside the passband, the blocking depth is OD > 5, thoroughly suppressing autofluorescence and laser interference.
Ion-assisted and sputtering deposition techniques are used to apply a hard coating, significantly extending the filter’s lifespan.

Fluorescent Filter Set For Alexa Fluor 405 Technical Datasheet

Item	Specification
Product Model	Alexa Fluor 405 Fluorescent Filter Set
Application	Fluorescence microscopy ( Alexa Fluor 405、Cascade Blue)
Excitation Filter	395/25 nm (CWL 395 nm, FWHM 25 nm), OD > 5, Tp> 80% Allowance for center wavelength and FWHM: +/-5nm Blocking depth: 200-1100nm@OD>5
Emission Filter	431/28 nm (CWL 431 nm, FWHM 28 nm), OD > 5, Tp> 90% Allowance for center wavelength and FWHM: +/-5nm Blocking depth: 200-1100nm@OD>5
Dichroic Mirror	DM411nm
Filter Sizes (EX & EM)	Ø25.0 mm × 3.5 mm mounted
Dichroic Mirror Size	36.0 mm × 26.0 mm × 1.0 mm
Angle of Incidence	0° (EX/EM), 45° (Dichroic)
Substrate Material	Fused Silica
Coating Type	Ion-assisted deposition + sputtered hard coating
Surface Quality	80/50 60/40 (per MIL-PRF-13830B)
Compatible Microscopes	Nikon, Olympus, Zeiss, Leica

Fluorescent Filter Set For Alexa Fluor 405 Applications

Long-Term Live Cell Imaging In live cell studies, dynamic tracking of Alexa Fluor 405-labeled mitochondria/endosomes requires continuous excitation. However, traditional filters often suffer from low excitation efficiency and poor durability due to soft coatings. The 395/25 nm excitation filter precisely matches the AF405 excitation peak and features a durable hard-coated surface.
Flow Cytometry In immunotherapy, sorting less than 0.01% of CAR-T cells is required. Traditional setups often have high crosstalk and autofluorescence, causing signal loss. The narrow-band emission filter 431/28 nm avoids autofluorescence peaks and suppresses channel leakage through its high blocking depth.
Nuclear Staining in Cell Imaging The cell nucleus is a core target in many biological studies. Traditional dyes like DAPI or Hoechst require UV excitation, placing demands on the microscope and causing interference with blue/green channels. Alexa Fluor 405 is excited near the edge of visible light (~401 nm), maintaining high SNR while minimizing channel interference and being compatible with LED excitation systems.
Fluorescent Probe In molecular probe or microsphere detection, signal intensity, resolution, and stability are key. This filter set enables detection of Alexa 405-labeled antibodies or probes, delivering stable, reproducible, and quantifiable signals—ideal for high-sensitivity diagnostics or nanobiomaterial development.