Edge Filter 835nm OD6 Broadband NIR Transmission Filter to 1800nm Overview

The 835nm OD6 edge filter is made of infrared fused silica, providing a high OD6 cutoff depth in the ultraviolet 200nm to visible light band below 835nm, completely blocking excitation light and background stray light, while offering ultra-wide and ultra-high broadband transmission in the short-wave infrared range of 835nm to 1800nm. It is mainly used in biomedical instruments such as infrared fluorescence imaging, in vivo imaging, multiphoton imaging, flow cytometry, and fluorescence spectroscopy for the detection of fluorophores in IRDye 800, Alexa Fluor 790, Cy7, and DyLight 800.

Coligh, as a manufacturer of edge filters and long-pass filters, supports the entire production process from film system design to spectral detection. We can customize cutoff wavelength, transition width, copper strip range, size, and OD value for OEM and ODM applications.

Edge Filter 835nm OD6 Broadband NIR Transmission Filter to 1800nm Key Features

It boasts the following core features:

1. Achieving an OD6 cutoff depth across a wide spectral range from UV to 835nm, effectively blocking intense excitation and stray light.
2. Maintaining over 90% to nearly 100% transmittance in the 835-1800nm ​​range, ensuring no signal attenuation in near-infrared and short-wave infrared regions.
3. It features an extremely steep cut-in edge at 835nm, enhancing the separation between excitation and emission.
4. We utilize high-quality UV-fused silica and infrared-fused silica as substrates, minimizing background fluorescence generated by the substrate itself under high-intensity illumination.
5. We employ IAD coating technology, resulting in a hard-coated film with extremely high density, scratch resistance, and long-term stability under varying temperature and humidity conditions.

Edge Filter 835nm OD6 Broadband NIR Transmission Filter to 1800nm Spectrum

Edge Filter 835nm OD6 Broadband NIR Transmission Filter to 1800nm   Specification

• 50% cut on：835+/-5nm
• 200-820nm@OD6 blocking depth
• Tp>=90%@830-1800nm

Stock List Of Optical Longpass Filters

Coligh Customize Capability Of Longpass Fluorescence Emission Filter

As a professional optical filter factory and supplier, we understand that fluorescence imaging and detection systems demand uncompromising spectral purity. We operate a complete set of independent production lines ranging from substrate processing to advanced thin-film coating, allowing us to precisely control every critical performance metric of your fluorescence longpass filter.

Whether you need to optimize the cut-on wavelength, sharpen the transition slope, or suppress background noise, we can fully customize dimensions, shapes, and incident angles (AOI) to fit your optical path. Furthermore, each batch undergoes strict high-precision spectrophotometric testing before shipment. We fully support flexible sampling, small-batch trials, massive production, and complete OEM/ODM services.

835nm Fluorophore Blocking Filter Applications

Near-Infrared Fluorescence Imaging Emission Filters

In near-infrared fluorescence imaging, commonly used fluorescent probes (such as IRDye 800, Alexa Fluor 790, Cy7, DyLight 800, etc.) typically have emission peaks above 800 nm. The excitation light intensity is much higher than the emitted fluorescence. If the excitation light leaks into the detector channel, it will mask the weak fluorescence signal, reducing the signal-to-noise ratio and image contrast. An 835 nm edge filter is used in the emission channel to allow near-infrared fluorescence above 835 nm to pass through, while using a deep OD6 cutoff to suppress excitation light below 835 nm and short-wavelength autofluorescence. Broadband transmission up to 1800 nm covers the emission bands of various near-infrared fluorescent dyes, making it suitable for multi-channel fluorescence imaging.

Flow Cytometry and Fluorescence Detection

Flow cytometry typically uses multiple lasers and multiple fluorescence channels. Cross-color mixing between channels is one of the main challenges. The OD6 835nm edge filter can be used in near-infrared fluorescence channels to deeply suppress excitation light, improve signal purity and detection accuracy, and reduce inter-channel interference. It enhances fluorescence detection sensitivity and resolution, reduces background noise and crosstalk, and is suitable for flow cytometry, cell sorting, and fluorescence immunoassay.

Raman Spectroscopy

In Raman spectroscopy, fluorescence background often masks weak Raman signals, especially in some samples where fluorescence intensity is much higher than the Raman signal. The 835nm edge filter can be used to suppress excitation light and short-wavelength fluorescence, improving Raman signal detection capability. Near-infrared excitation (e.g., 785 nm, 830 nm) reduces fluorescence, and broadband NIR transmission is suitable for detecting Raman signals in the 835–1800 nm range. It improves the Raman signal-to-noise ratio and reduces fluorescence background interference, making it suitable for materials analysis, chemical detection, and biological Raman spectroscopy.