Product Description
Aixtron ZnSe Witness Sample Optical Window – 1″ Diameter, Custom-Coated Dichroic Mirror for Laser and IR Systems
This premium Zinc Selenide (ZnSe) witness sample from Aixtron, a top-tier producer of advanced semiconductor and optical deposition equipment, offers exceptional value for R&D, prototyping, or optical system upgrades. As a quality-verification piece from a coating run, it’s a budget-friendly alternative to custom-ordered optics without sacrificing performance.
Aixtron is a world-leading provider of deposition equipment for the semiconductor and optical industries, and their witness samples represent the same high-quality standards used in their production tools.
Key Specifications
| Specification | Details |
|---|---|
| Manufacturer | Aixtron SE |
| Shape | Plano-plano disk (flat on both sides) |
| Diameter | 1 inch (25.4 mm) |
| Thickness | 1.5 mm |
| Substrate Material | Zinc Selenide (ZnSe) – CVD-grown, laser-grade |
| Surface Quality | 40/20 scratch-dig standard for reliable infrared use |
| Transmission Range (ZnSe) | 0.6 μm (visible) to 22 μm (far-IR) |
| Condition | Gently used as a witness sample – minor surface marks, small central spot, otherwise top functional condition |
Advanced Custom Coatings
This witness sample features two distinct, custom-designed coatings, making it a true dichroic optic:
| Surface | Coating Type | Specification | Function |
|---|---|---|---|
| S1 | High-Reflectivity (HR) | R > 98% at 1.06 μm (Nd:YAG laser wavelength) paired with T > 90% at 3.5 μm | Enables dichroic mirroring or beam splitting – reflecting near-IR while transmitting mid-IR |
| S2 | Anti-Reflection (AR) | Optimized for the 3.0-5.0 μm mid-IR band at a 45° angle of incidence | Reduces losses in angled setups common in IR systems |
These coatings enable selective reflection of near-IR light while transmitting mid-IR wavelengths, making it an ideal dichroic optic for multi-spectral applications.
Material Advantages – Laser-Grade Zinc Selenide
The genuine CVD-grown ZnSe material boasts a distinctive yellow-orange translucence and wide transmission range from 0.6 μm to 22 μm. Key properties include:
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Broadband IR Transmission: Covers all key IR bands including the 3-5µm MWIR and 8-14µm LWIR atmospheric windows .
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Low Absorption: Exceptionally low absorption coefficient (<0.0005 cm⁻¹ at 10.6 µm) minimizes thermal lensing and power loss in high-power applications .
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High Thermal Shock Resistance: ZnSe can withstand rapid temperature changes, making it suitable for demanding environments .
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Non-Hygroscopic: Unlike some IR materials, ZnSe does not absorb moisture, ensuring long-term stability .
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Visible/NIR Transmission: Partial transmission in the visible spectrum (600-900nm) allows for easy alignment with visible lasers (e.g., HeNe at 633nm) .
Important Safety Note: ZnSe is a toxic material. Always handle with rubber or plastic gloves to avoid contamination. Wash hands thoroughly after handling. Never ingest or inhale dust .
What is a Witness Sample?
A witness sample is a small optical flat coated simultaneously with production optics to:
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Verify coating quality without touching primary optics
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Measure thickness and uniformity via spectrophotometry
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Test environmental durability (humidity, adhesion, abrasion)
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Validate spectral performance before product shipment
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Archive coating runs for traceability and quality assurance
This practice is standard in precision optical coating, where primary optics are too valuable to risk for destructive or contact testing.
Applications
Laser Systems:
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Efficient beam combining and splitting in Nd:YAG (1.06 μm) setups for materials processing, medical tools, or rangefinding
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Dichroic separation of pump and signal beams in solid-state lasers
Thermal Imaging and FLIR:
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Windows or filters in mid-IR cameras (3-5 μm) for surveillance, environmental analysis, or maintenance diagnostics
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Beam combining in multi-spectral imaging systems
Infrared Spectroscopy:
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Essential for gas analyzers, chemical sensors, or FTIR systems demanding low absorption and high clarity
Photonics R&D:
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Great for lab experiments, alignment fixtures, or custom builds in compact, angle-optimized designs
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Prototyping multi-spectral optical systems
Defense and Aerospace:
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Dichroic optics for missile seekers, target designation, and surveillance payloads
Condition
GENTLY USED AS WITNESS SAMPLE
MINOR SURFACE MARKS – COSMETIC ONLY
SMALL CENTRAL SPOT – DOES NOT AFFECT FUNCTION
OTHERWISE TOP FUNCTIONAL CONDITION
SHIPS IN ORIGINAL PROTECTIVE PACKAGING
RMI COMPLIANT FOR RESPONSIBLE SOURCING
⚠ HANDLING NOTE: Handle with care – clean with isopropyl alcohol and lint-free cloth using proper optical cleaning techniques. ZnSe is brittle; avoid drops or exposure to contaminants. Always wear gloves when handling.



