Double-Band Bandpass Filters from Shape Optics Technologies Pte Ltd are engineered to transmit two targeted wavelength regions simultaneously, making them ideal for optical systems that require multi-spectral isolation from a single optical path.
These filters combine high transmission with deep blocking, enabling clean signal separation in applications such as fluorescence microscopy, spectral analysis, imaging systems, and laser-based instrumentation. Standard configurations include popular wavelength pairs such as 500 & 655 nm and 525 & 940 nm, while fully customized designs are available to meet specialized requirements.
Key Features
- Dual-Band Functionality – Precisely transmits two distinct wavelength bands while blocking all others
- High Transmittance – T ≥ 90% in passbands for maximum signal efficiency
- Strong Out-of-Band Blocking – OD ≥ 3 ensures excellent background suppression
- Customizable Spectral Design – CWL, bandwidth, and OD tailored to your application
- High Precision & Stability – Tight tolerances for reliable performance in sensitive optical systems
Spectrum Transmission
Standard double-band designs provide two well-defined transmission windows with steep spectral edges. If standard wavelength combinations do not meet your needs, custom spectral solutions can be developed based on your required center wavelengths, bandwidths (FWHM), and blocking ranges.
Coating Quality & Environmental Reliability
All double-band filters are qualified to stringent military and industrial standards:
- Adhesion Test (MIL-C-675C) – No blistering or peeling after repeated tape removal
- Thermal Cycling – −62 °C to +71 °C with no coating detachment
- Abrasion Resistance (MIL-C-675C / CCC-C-440) – No surface damage after 25 cycles at 1.0 lb load
- Humidity Resistance – 95–100% RH at 49 °C for 24 h without defects
- Solvent Resistance – Stable after acetone and alcohol exposure
- Salt Spray Test – 100 h at 35 °C, 5% salt concentration with no degradation
Standard Specifications
| Model (CWL) | Transmittance | FWHM (nm) | Optical Density |
|---|---|---|---|
| 310 ± 400 nm | T ≥ 75% & T ≥ 85% | 10 ± 2 | OD ≥ 3 @ 200–800 |
| 500 ± 655 nm | T ≥ 90% | 10 ± 2 | OD ≥ 3 @ 200–1100 |
| 525 ± 850 nm | T ≥ 90% | 250 ± 20 & 850 ± 10 | OD ≥ 3 @ 200–1100 |
| 525 ± 940 nm | T ≥ 90% | 250 ± 20 & 850 ± 10 | OD ≥ 3 @ 200–1100 |
| 660 ± 860 nm | T ≥ 90% | 35 ± 5 & 50 ± 5 | OD ≥ 3 @ 200–1100 |
| 1202 ± 1300 nm | T ≥ 90% | 30 ± 5 & 30 ± 5 | OD ≥ 3 @ 200–1100 |
Typical Applications
- Fluorescence Microscopy – Isolation of excitation and emission bands
- Laser Systems – Dual-wavelength laser separation or detection
- Astronomy & Spectroscopy – Targeted spectral line observation
- Environmental Monitoring – Multi-band detection of gases or pollutants
- Industrial Optical Systems – Multi-spectral inspection and analysis