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5000nm (5.0μm) Mid IR Longpass Filter
5000nm mid ir longpass filter is an optical filter designed to transmit wavelength longer than 5000nm and block the others. Coligh manufactures ir longpass filter.
- 50% Transmission Wavelength at 5000 nm
- >90% High Transmission
- Broadband Blocking and Transmission
- Insensitive to Angle of Incidence
- Hard First-Surface Dielectric Coating
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5000nm Mid-infrared Longpass Optical Filter Description
The 5000nm (5.0μm) mid-infrared long-wave pass filter produced by Coligh is a high-performance optical filter designed for infrared optical systems.
- The transmission band of this filter is from 5300nm to 13000nm, and the transmittance is greater than or equal to 80%, which can retain useful signals to the greatest extent. It is compatible with key wavelengths such as CO2 lasers and thermal radiation signals, and is suitable for a variety of infrared light sources and detectors.
- At the same time, the cut-off depth from 400nm to 4500nm is less than 1%, which is greater than or equal to OD2, ensuring that visible light, near infrared, and part of mid-infrared are strictly suppressed.
- We use hard coating technology, and the long-wave pass product characteristics make this filter insensitive to angle changes, suitable for changes from small incident angles to large incident angles.
5000nm (5.0μm) Mid IR Longpass Filter Technical Datasheet
| Parameter | Specification |
| Cut‑on Wavelength (50% T) | 5000nm |
| High‑Transmission Band | ≥ 90% @ 5000nm-13000nm |
| Blocking Region | 400-4500nm |
| Optical Density (OD) | OD ≥ 2 (T < 1%) |
| Substrate Materials | White glass, Sapphire, Silicon, Fused Silica, Zinc Selenide |
| Coating Type | Hard first‑surface all‑dielectric |
| Surface Quality | 80-50, 60‑40, 40-20 scratch‑dig (MIL‑PRF‑13830B) |
| Clear Aperture | ≥ 90% of full aperture |
| Available Diameters | Ø12.7 mm, Ø25.4 mm, Ø50mm, Ø100 mm or custom |
| Thickness | 0.5mm, 1.0mm or custom |
5000nm (5.0μm) Mid IR Longpass Filter Applications
- Gas sensing and detection
Gas molecules such as CH₄ and CO₂ have characteristic absorption peaks in the mid-infrared band, but they are often interfered by ambient light and radiation from other bands in actual detection. It is necessary to accurately separate the target wavelength to improve the detection sensitivity. The 5000nm long-wave pass filter can strictly block the interference light <5.0μm, only transmit the absorption wavelength of the target gas, and ensure that the detector receives enough effective signals. - Thermal imaging system
The thermal radiation of objects is mainly concentrated in the 8-14μm far-infrared band, but the short-wave infrared in the environment will reduce the contrast of thermal imaging. The 5000nm mid-infrared long-wave pass filter can strictly cut off the stray light <5.0μm and only allow the thermal radiation signal 5300-13000nm signal to pass. In this way, the thermal imager can still work stably in a strong light environment. - CO₂ laser cutting
The wavelength of CO₂ laser is 10.6μm, but the short-wave reflected light during the processing may damage the detector or interfere with the control system. This filter can block short-wave reflected stray light and project a 10.6um laser beam. - Spectral analysis
Fourier infrared spectroscopy needs to separate the characteristic absorption peaks of the material, but the wide-spectrum light source contains irrelevant bands, which affects the analysis resolution. This long-pass filter can transmit mid-to-far infrared light above 5.0μm and focus on the target molecular vibration/rotation characteristic peaks. Improve the clarity of the material characteristic peaks
