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Frequently asked questions

Long pass filters are used in a variety of applications other than Raman spectroscopy. They are commonly used as band separators in precision spectroscopy, and are useful as blocking filters in various photometric instruments, helping to eliminate optical distortions.

Owing to their implicit longer wavelength-dependent transmittance, long pass filters are also ideal for eliminating leakage of excitation light in fluorometry and maximising the acquisition of sample fluorescence.

Although long pass filters can be used independently, they can also be combined with short pass filters aligned to filter the same light source.

Protective packaging: When not in use, store filters in protective packaging to protect them from moisture. Many optics come in moisture-resistant packaging.

Controlled Storage Conditions: Store filters in a controlled environment where humidity levels remain within acceptable limits. This may involve using air conditioning or dehumidifying storage areas.

Regular maintenance and inspection: Check your filters regularly for any signs of moisture damage, such as fogging or condensation. Clean according to the manufacturer's instructions, making sure no moisture is introduced during the cleaning process.

Avoid direct contact: When handling long pass filters, avoid touching the surface of the filter directly with your hands. It's best to use clean pliers or gloves to prevent grease and dirt from adhering to the filter.

Professional cleaning method: If the high pass filter needs cleaning, it is usually wiped gently with an optical fiber-free cloth and a suitable solvent (such as isopropyl alcohol).

Yes, our filters, whether they are long-pass/short-pass filters or UV/IR cut-off filters, are customizable. Optolong will develop a filter that meets your needs based on your requirements.

Long pass filters are mainly made of materials such as fused quartz and B270. For 680 nm high pass filters as well as low pass filters and UV/IR cut filters, materials used include fused silica, B270, float glass, and absorbing glass.

These materials were chosen for their optical properties, suitable for filtering specific wavelengths of light and ensuring the filter's durability and effectiveness.