ZnSe AR-coated plano-plano window 1 inch 5mm

Product Description

ZnSe Plano-Plano Optic Window – 1″ Diameter, 5mm Thick, AR Coated

This high-quality Zinc Selenide (ZnSe) plano-plano optic window measures 1 inch (25.4mm) in diameter and 5mm in thickness, sourced from a reputable US manufacturer II‑VI Incorporated (now part of Coherent Inc.) . It features an anti-reflective (AR) coating on both sides, optimized for minimal reflection and enhanced transmission in the infrared spectrum.

Zinc selenide is one of the materials of choice for CO₂ laser optics operating at 10.6 microns . Its broad transmission band, coupled with its minimal absorption, makes it an ideal substrate for optical components used in infrared applications such as thermal imaging and high-powered laser systems . An additional advantage of using ZnSe is its transmission within the visible region, specifically 632.8nm, allowing for HeNe laser pairing for alignment purposes .

The optic appears in good surplus/used condition with minor cosmetic marks from handling or storage, but these are insignificant and do not impact its optical performance or usability—ideal for precision applications.

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Key Specifications

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Material & Coating Advantages

High-Purity Zinc Selenide (ZnSe) :

• Broadband IR Transmission: 0.6 µm to 21 µm, covering the visible red through far-IR, including the critical 8-14 µm LWIR atmospheric window

• Low Absorption: Exceptionally low absorption at 10.6 µm (<0.0005 cm⁻¹) makes it ideal for high-power CO₂ laser systems, minimizing thermal lensing and power loss

• CO₂ Laser Optimization: ZnSe is the material of choice for CO₂ laser optics operating at 10.6 microns

• Visible Transmission: ZnSe transmits in the visible region, specifically 632.8nm, allowing for HeNe laser pairing for alignment purposes

• Non-Hygroscopic: Unlike some IR materials, ZnSe is stable in normal atmosphere up to 250°C

Anti-Reflective (AR) Coating :

• Applied to both sides for optimal performance

• Reduces surface reflections and increases transmission in the specified range

• The characteristic greenish reflection in visible light indicates high-performance thin-film layers

• Based on Thorlabs’ comparable products, similar coatings achieve Ravg < 1.0% within the 7.0-12.0 µm range

• The -E3 coating from Thorlabs for 7-12µm has demonstrated CW damage thresholds of 1000 W/cm at 10.6 µm

Thickness Advantage – 5mm Profile :
The substantial 5mm thickness provides:

• Enhanced mechanical strength and rigidity

• Improved thermal stability for high-energy environments

• Better heat dissipation in high-power applications

• Reduced risk of breakage during handling and mounting

• Performance beyond thinner (2-3mm) commercial variants

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Surface Quality Note – Cosmetic Marks Only

The optic shows minor cosmetic marks from handling or storage. These are:

• Surface-level only – do not penetrate into the substrate

• Outside the critical optical path – does not affect transmitted beam

• Cosmetic only – no impact on optical performance or usability

• Typical of surplus optics – does not compromise IR transmission

The optical surfaces remain fully functional for precision IR applications.

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Applications

CO₂ Laser Systems (10.6 μm) :

• Protective windows for industrial cutters, engravers, and markers

• Beam delivery components in high-power CO₂ laser systems

• Debris shields for scan lenses (also known as “fragmentation windows”)

• The AR coating reduces energy loss and prevents back-reflections that could damage laser sources

Thermal Imaging and FLIR :

• Forward-looking infrared (FLIR) cameras and thermal sensors for night vision, surveillance, or medical thermography

• ZnSe’s broad transmission range encompasses the MWIR and LWIR thermal bands

• Applications in thermography, night vision devices, and target tracking

Spectroscopy and Analytical Instruments :

• FTIR (Fourier-Transform Infrared) spectrometers and gas analyzers

• High optical clarity for accurate measurements

• ATR prisms for spectroscopy applications

Aerospace and Defense :

• Missile guidance systems and IR countermeasures

• Environmental monitoring equipment

• Durable material for demanding environments

Research and Development :

• Custom setups in optics labs for beam steering, focusing

• Substrates in experimental IR photonics

• IR spectroscopy, night vision devices, and target tracking systems

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Condition

GOOD SURPLUS/USED CONDITION
MINOR COSMETIC MARKS FROM HANDLING OR STORAGE – DOES NOT AFFECT OPTICAL PERFORMANCE
OPTICAL SURFACES: CLEAN, COATINGS INTACT
AR COATING: Characteristic greenish reflection visible
READY FOR IMMEDIATE INTEGRATION

⚠ CRITICAL HANDLING NOTE: Zinc selenide has a Knoop hardness of 120, making it relatively soft and easily scratched . Always wear gloves when handling . ZnSe is a hazardous material – for safety, please follow all proper precautions . Thorlabs recommends disposing of ZnSe components properly and offers a return service for disposal . Avoid mechanical shock, store in a dry environment, and clean only with approved optical solvents and lint-free cloths if absolutely necessary. Do not exceed 250°C in normal atmosphere .