GMNF-UV High-Performance UV-Grade Metallic Neutral Density Filter
| Origin | Beijing, China |
|---|---|
| Manufacturer Type | Authorized Distributor |
| Regional Origin | Domestic (China) |
| Model | GMNF-UV |
| Price Range | USD 0.15–75.00 (varies by diameter and OD) |
| Component Category | Optical Element |
| Optical Density (OD) | 0.1–3.0 |
| Transmission (T) | 79%–0.1% |
| Design Wavelength | 300 nm |
| Available Diameters | Φ12.5 mm, Φ25 mm, Φ50 mm |
| Substrate Material | UV-Fused Silica |
| Coating Type | Metallic (Chromium-based) |
| Surface Quality | 40–20 scratch-dig |
| Flatness | λ/4 @ 633 nm |
| Parallelism | <3 arcmin |
| Damage Threshold | >0.5 J/cm² @ 300 nm, 10 ns pulse |
Overview
The GMNF-UV is a precision-engineered metallic neutral density (ND) filter designed specifically for demanding ultraviolet (UV) optical applications where high transmission stability, spectral uniformity, and laser damage resistance are critical. Unlike absorptive polymer or gelatin-based ND filters—whose performance degrades rapidly under UV exposure—the GMNF-UV employs a thin-film chromium metal coating deposited onto high-purity UV-fused silica substrates. This architecture ensures exceptional photostability across the deep UV range (down to 200 nm), minimal wavelength-dependent shift in optical density, and negligible fluorescence or outgassing under vacuum or high-intensity irradiation. The filter operates on the principle of controlled metallic reflection and absorption, delivering highly repeatable attenuation without introducing polarization bias or spectral distortion—making it suitable for quantitative radiometry, UV laser power management, spectrophotometer calibration, and fluorescence microscopy excitation control.
Key Features
- UV-optimized design: Specified and validated at 300 nm, with verified performance from 200–400 nm; transmission curves available upon request
- Metallic thin-film coating: Chromium-based multilayer stack enabling low thermal drift, high environmental stability, and resistance to humidity-induced degradation
- High-precision substrate: UV-grade fused silica with ≤λ/4 surface flatness (633 nm reference) and <3 arcmin parallelism—critical for collimated beam applications
- Multiple physical formats: Standard diameters of Φ12.5 mm, Φ25 mm, and Φ50 mm; each OD value assigned unique part numbers (e.g., GMNF-UV-D25-020 for OD 2.0, 25 mm)
- Traceable optical density: OD values calibrated per ISO 9050 and ASTM E275; certified test reports include spectral transmittance data and measurement uncertainty budgets
- Low wavefront distortion: Maintains beam quality in interferometric and holographic setups; compatible with high-NA imaging systems
Sample Compatibility & Compliance
The GMNF-UV is compatible with standard SM-threaded lens mounts (e.g., SM1, SM25), kinematic mirror mounts, and custom optical breadboard adapters. Its UV-fused silica substrate meets MIL-O-13830A surface quality standards (40–20 scratch-dig), and the metallic coating passes ISO 9211-4 adhesion testing (tape peel + humidity cycling). For regulated environments—including ISO/IEC 17025-accredited calibration labs and FDA-regulated analytical instrumentation—the filter supports full traceability to NIST-traceable radiometric standards. Documentation packages include Certificate of Conformance (CoC), spectral transmittance data sheets, and optional ISO 17025-accredited calibration certificates (per customer-specified OD points and wavelengths).
Software & Data Management
While the GMNF-UV is a passive optical component, its integration into automated optical systems is supported via standardized mechanical interfaces and documented spectral datasets. Full spectral transmittance curves (200–1100 nm, 1 nm resolution) are provided in ASCII and CSV formats for import into Zemax OpticStudio, FRED, or MATLAB-based system modeling workflows. For users operating under GLP/GMP or FDA 21 CFR Part 11 requirements, batch-specific test records—including OD verification at multiple spatial positions across the clear aperture—are archived for audit readiness. Custom labeling (including QR-coded lot IDs and machine-readable OD metadata) is available upon order.
Applications
- Laser power attenuation in UV photolithography alignment systems and excimer laser beam delivery paths
- Reference-grade attenuation in UV-VIS spectrophotometer stray-light correction and detector linearity validation
- Excitation light control in UV-enhanced fluorescence lifetime imaging (FLIM) and time-resolved spectroscopy
- Beam balancing in multi-channel UV Raman spectroscopy setups requiring matched intensity ratios
- Vacuum-compatible optical density standards for space-borne UV astronomy sensor calibration
- Photobiological safety testing per IEC 62471, where precise UV radiant exposure control is mandatory
FAQ
What is the damage threshold specification for continuous-wave (CW) UV sources?
The GMNF-UV is rated for >500 W/cm² at 300 nm under CW illumination, assuming proper heat sinking and beam homogenization. Derating is recommended above 350 nm due to increased substrate absorption.
Is this filter polarization-sensitive?
No—metallic ND filters exhibit negligible polarization dependence (<0.5% transmission variation over 0–360° azimuthal rotation) within the specified angular acceptance (±5°).
Can I use GMNF-UV filters in vacuum environments?
Yes. UV-fused silica substrate and Cr-based coating are non-outgassing per ASTM E595; total mass loss (TML) <0.5%, collected volatile condensable materials (CVCM) <0.05%.
Do you provide custom OD values or non-standard diameters?
Custom OD values (e.g., OD 1.7, OD 2.5) and diameters up to Φ75 mm are available under OEM agreement with minimum order quantities and extended lead times.
How is optical density verified during manufacturing?
Each filter undergoes dual-beam UV-VIS spectrophotometric verification using a NIST-traceable reference spectrometer (PerkinElmer Lambda 950) with deuterium lamp source and calibrated photodiode detector; OD uncertainty ±0.015 (k=2) at 300 nm.
