Near Infrared 700 - 2500 nm Long Pass Filters
A long pass filter in the mid-infrared range between 700 nm to 2500 nm allows longer wavelengths to pass through while blocking shorter wavelengths up to a certain cut off point. More information on the uses and applications of near infrared long pass filters as well case studies examples of filters we have manufactured can be found below.
We design and manufacture custom near infrared long pass filters between 700 and 2500 nm to any custom specification. We hold a wide range of stock substrates such as Glass, Silicon, Sapphire, Infrared Quartz, Calcium Fluoride and more to enable fast prototype development. We are able to design, manufacture and dice filters to their finished size all in house with lead times as little as 2 weeks.
Please contact us to discuss your specific requirements.

Case Studies

910 nm Long Pass Filter

1000 nm Long Pass Filter

1410 nm Long Pass Filter
Applications

Spectroscopy:
Long pass filters are essential in spectroscopy applications for separating and isolating specific wavelengths of light. They help in analysing the spectral characteristics of materials and samples by blocking unwanted shorter wavelengths and allowing only the desired longer wavelengths to pass through.

Order Sorting Filters:
These are used in diffraction grating based spectrometers to cancel out higher order bands in such instruments which can cause interference across the intended measuring bands.

Fluorescence Microscopy:
In fluorescence microscopy, long pass filters are used to block excitation light (shorter wavelengths) while allowing emitted fluorescence light (longer wavelengths) to pass through. This helps in capturing clear and high-contrast fluorescence images of biological samples and materials.

Chemical Analysis:
Long pass filters are used in various chemical analysis techniques such as Raman spectroscopy and infrared spectroscopy. They help in isolating specific vibrational modes of molecules by blocking interfering shorter wavelengths and enhancing the signal-to-noise ratio of the measurements.

Remote Sensing:
Long pass filters are used in remote sensing applications for environmental monitoring, agriculture, and geological surveys. They help in filtering out unwanted background light and atmospheric interference, allowing the detection of specific near-infrared signatures from the target areas.

Communications:
Long pass filters play a role in optical communications systems by separating different channels of information carried by light signals, i.e. isolating specific wavelengths for signal processing and transmission in fibre optic networks.