Features
- High Transmission in Passband: Delivers >85% transmission below the cutoff wavelength while effectively blocking longer wavelengths.
- Precise Cutoff Control: Features a sharp spectral edge (90%–10% < 10 nm) for accurate wavelength separation in precision optical systems.
- Broad Application Versatility: Widely used in fluorescence instrumentation, heat rejection, and color filtering across UV, VIS, and IR ranges.
- Durable & Environmentally Stable: Multi-layer dielectric coatings ensure long-term stability in laboratory, industrial, and field environments.
- Customizable Designs: Available with custom cutoff wavelengths, sizes, and substrates to match specific system requirements.
General Description
Shape Optics offers high-performance Short Pass Filters engineered to transmit wavelengths shorter than a defined cutoff while blocking longer wavelengths with high optical density. These filters are essential for applications that require precise wavelength selection, such as fluorescence excitation, thermal/IR rejection, and optical color separation.
Manufactured using advanced multi-layer dielectric coating technology, SOT short pass filters provide high transmission, steep cutoff slopes, and deep blocking (OD > 4). Built on optical glass or fused silica substrates, they deliver excellent durability and consistent performance in both research and industrial optical systems.
Spectrum Transmission Curves
Standard cutoff wavelengths are available for common applications.
If standard products do not meet your needs, custom short pass filters can be designed to your exact cutoff wavelength, bandwidth, blocking level, size, and substrate.
Contact us to discuss your application or request a custom quotation.
Coating Quality & Environmental Reliability
All SOT short pass filters are tested according to MIL-C-675C and CCC-C-440 standards:
- Adhesion Test: LT-90 tape test (3 removals), no blistering or peeling
- Temperature Cycling: −62 ±1 °C to 71 ±1 °C, no coating detachment
- Abrasion Resistance: 1.0 lb gauze test, 25 cycles, no surface damage
- Humidity Resistance: 49 ±2 °C, 95–100% RH for 24 h, film intact
- Solvent & Cleaning: Acetone and alcohol exposure, no peeling or scratches
- Salt Spray: 100 h at 35 °C with 5% NaCl, no corrosion
Standard Specifications
| Parameter | Specification |
|---|---|
| Substrate | Optical glass, Fused Silica |
| Diameter Tolerance | +0 / −0.2 mm |
| Thickness Tolerance | ±0.1 mm |
| Clear Aperture | > 80% of diameter |
| Surface Quality | 60-40 scratch & dig |
| Coating Type | Multi-layer dielectric |
| Transmission | > 85% |
| Spectral Slope | 90% → 10% < 10 nm |
| Blocking | OD > 4 |
Standard Products
| Description | Cut-off (nm) | Thickness (mm) | Item # (Ø25 mm) | Item # (50 × 50 mm) |
|---|---|---|---|---|
| UV Short Pass Filter | 265 | 1 | XUS0265 | ZUS0265 |
| UV Short Pass Filter | 300 | 1 | XUS0300 | ZUS0300 |
| UV Short Pass Filter | 325 | 1 | XUS0325 | ZUS0325 |
| UV Short Pass Filter | 350 | 1 | XUS0350 | ZUS0350 |
| VIS Short Pass Filter | 450 | 1 | XHS0450 | ZHS0450 |
| IR Short Pass Filter | 900 | 1 | XIS0900 | ZIS0900 |
| IR Short Pass Filter | 960 | 1 | XIS0960 | ZIS0960 |
Applications
Short pass optical filters are widely used in:
- Fluorescence Instrumentation – Select excitation wavelengths while blocking emission or background light
- Heat Rejection – Block IR wavelengths while passing visible light (e.g., projection systems)
- Color Filtering – Improve contrast and image quality in optical imaging systems
- Scientific & Industrial Optics – Precise wavelength management across UV, VIS, and IR bands
SOT Strengths & Capabilities
SOT is a trusted supplier of precision optical filters, combining advanced thin-film coating expertise, strict quality control, and custom engineering capability. Our short pass filters are designed to meet demanding performance and environmental requirements across telecommunications, medical instrumentation, environmental monitoring, and industrial optics.