Double-band bandpass filter

1.  Features

• Dual-band Functionality: The Double-band bandpass filters are designed to transmit two specific wavelength ranges while blocking other wavelengths, making them ideal for applications that require filtering of multiple bands simultaneously.
• High Transmittance: With high transmittance (T ≥ 90%) across the specified wavelength ranges, these filters ensure minimal loss of light, offering excellent performance for precision applications.
• Customizable Wavelength Ranges: The filters can be customized to support specific wavelength bands, offering versatility for use in various scientific, industrial, and optical applications.
• Strong Optical Density: These filters provide high optical density (OD ≥ 3) to ensure excellent attenuation outside the selected bands, enabling clear and sharp optical performance.
• Precise Performance: These filters are engineered to maintain their transmission properties within tight tolerances, ensuring high-quality results even in sensitive optical systems.

2. General Description

The Double-band Bandpass Filter is a specialized optical component that transmits two distinct ranges of wavelengths while blocking light outside of these ranges. These filters are essential for applications such as fluorescence detection, spectral analysis, and imaging systems where specific wavelength bands need to be isolated from broad-spectrum light sources.

Our filters are known for their excellent performance with high transmittance (T ≥ 90%) and strong optical density (OD ≥ 3). This enables them to transmit light with minimal attenuation in the desired ranges while significantly reducing the intensity of out-of-band light. With a range of standard options, including 500&655nm, 525&940nm, and others, these filters can be customized for different applications, providing an optimal solution for users working with complex optical systems.

These filters are widely used in scientific research, industrial applications, and environmental monitoring, where the need to isolate light in multiple specific wavelength ranges is crucial.

3. Spectrum Transmission Curves

For the double-band filters, the standard wavelength ranges are:

• 500 & 655nm: A bandpass filter allowing transmission at 500nm and 655nm, blocking all light outside these bands.
• 525 & 940nm: This filter transmits light in the 525nm and 940nm bands while blocking out-of-band light.

If the standard components do not meet your specific requirements, we can provide customized services upon request, offering tailored solutions that match your exact needs.

4. Coating Quality

a) Adhesion Test: Compliant with MIL-C-675C military standards, an adhesion test involved applying a tape that meets LT-90 specifications onto the lens film layer. The tape was affixed fully and then removed vertically. This procedure was performed three times, resulting in no blistering or peeling.

b) Temperature Test: In line with MIL-C-675C specifications, test pieces were subjected to temperatures of -62±1℃ and 71±1℃. After maintaining them at room temperature (16℃~32℃) for two hours, the adhesion test was repeated, confirming no film detachment.

c) Abrasion Resistance Test: Conforming to MIL-C-675C and CCC-C-440 standards, the abrasion resistance test involved a gauze tester applying a minimum force of 1.0 lbs (0.45 kg) to the film. This was repeated 25 times with gauze widths of 1/4 inch (6.4mm) and 3/8 inch (9.5mm), ensuring no damage occurred to the film surface.

d) Humidity Test: Under MIL-C-675C criteria, the test piece was placed in a controlled temperature and humidity chamber set to 49 ±2℃ and 95%~100% humidity for 24 hours. The film remained intact, with no peeling, scratches, or other defects.

e) Solvent and Cleaning Testing: Following MIL-C-675C specifications, test pieces were exposed to room temperature conditions (16℃~32℃) and tested with acetone and alcohol for at least 10 minutes each. After air drying and subsequent cleaning with a cotton cloth soaked in alcohol, the film surface showed no signs of peeling or scratches.

f) Salt Spray Test: After 100 hours in a 35°C environment with a 5% saltwater concentration, the film showed no signs of damage.

5. Standard Specifications

6. General Applications and Examples

The Double-band Bandpass Filter is highly versatile and widely used in a variety of applications:

• Fluorescence Microscopy: Used to isolate specific fluorescence emission wavelengths while blocking other background light.
• Laser Systems: Filters specific wavelengths of laser light to ensure only the desired bands are transmitted for precision work.
• Astronomy and Spectroscopy: Enables the capture of light from specific spectral lines, useful in space observation and material analysis.
• Environmental Monitoring: Filters specific wavelength bands for detecting pollutants or other compounds in the atmosphere.
• Industrial Optical Systems: Used for quality control and analysis in manufacturing processes by isolating certain spectral bands.

These filters are custom-designed for high-end performance and are suitable for both laboratory and field use, ensuring accurate results and consistent quality.

7. SOT Strengths and Capabilities

Shape Optics Technologies Pte Ltd (SOT) is committed to providing high-quality optical filters with exceptional precision and durability. Our filters are widely used in research, industrial, and scientific applications, ensuring performance and longevity. With advanced manufacturing capabilities, we offer tailored solutions to meet the specific needs of our clients, including custom wavelengths, coatings, and filter types. Our quality control processes ensure each product adheres to strict standards, providing you with reliable performance in critical applications.

8. Standard Products