germanium LWIR beam splitter 8-12µm diffractive – LOT OF 2

Product Description

High-Quality Defense-Grade Germanium LWIR Beam Splitter (2 inch diameter) – Premium Surplus Optics for Advanced IR Applications

Elevate your infrared projects with these exceptional defense-grade optics from a historic U.S. military initiative! Crafted by Infrared Optical Products, Inc. (Farmingdale, NY), these germanium (Ge) beam splitters are engineered for superior performance in the 8-12µm long-wave infrared (LWIR) band, perfect for high-stakes thermal imaging and sensor systems.

Each is a precision-polished, flat circular disk measuring 2 inches (50.8mm) in diameter, boasting an anti-reflective (AR) coating on one side for exceptional transmission efficiency (>98% in the optimized band) and a bare side featuring a high-efficiency diffractive (HED) grating structure for accurate beam splitting. The custom ~30:70% reflection-to-transmission ratio enables precise asymmetric division, ideal for prioritizing signal paths in sophisticated setups.

Visually, these pieces display captivating iridescent hues (blue, green, purple) from thin-film interference under visible light, with a mirror-like finish on the bare side—hallmarks of top-tier IR craftsmanship.

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Two Thickness Variants

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Key Specifications

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Optical Design & Functionality

These beam splitters are far from standard catalog components. Their sophisticated design serves specific advanced applications:

• Anti-Reflective (AR) Coating: The dielectric multilayer coating on one side ensures maximum transmission (>98%) in the 8-12µm band, minimizing signal loss in the transmitted path .

• High-Efficiency Diffractive (HED) Grating: The bare side features a precisely etched diffractive structure that efficiently splits the incident beam . This is not a simple metallic or dielectric beamsplitter coating, but a true diffractive optic that can offer precise control over the beam’s direction and intensity distribution.

• Custom 30:70 Split Ratio: This asymmetric ratio is uncommon in standard catalog optics and is tailored for specific system architectures where one arm of the optical path requires a different power level than the other . This could be for prioritizing a sensor channel, balancing signal-to-noise ratios, or creating a specific reference path.

• Germanium Substrate: Germanium is the material of choice for LWIR optics due to its high refractive index (~4.0), low absorption (<0.02/cm) in the 8-12µm band, and excellent thermal stability . High-purity, defense-grade Ge ensures minimal signal loss and consistent performance.

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Applications

Defense & Aerospace :

• Missile Guidance Seekers: Beam splitting for target tracking and discrimination

• Thermal Weapon Sights (TWS) : Advanced night vision and targeting

• Focal Plane Arrays (FPAs) : Splitting optical paths for multi-spectral sensing

• Reconnaissance Systems: High-performance thermal imaging for intelligence gathering

• Head-Up Displays (HUDs) : LWIR projection and imaging

Scientific Research :

• Spectroscopy Instruments: FTIR and other IR analysis techniques

• Laser Research: CO₂ laser (10.6µm) beam management

• Multi-Spectral Imaging: Simultaneous imaging in different wavelength bands

Industrial & Commercial :

• Advanced Thermal Imaging: High-end thermal cameras and sensors

• Drone Surveillance: Lightweight 2mm version for UAV payloads

• Industrial IR Testing: Non-contact temperature measurement

• Night Vision Enhancement: Improving low-light imaging systems

R&D Prototyping :

• Custom sensor integration

• Beam path management in complex optical systems

• Testing advanced diffractive optics concepts

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Provenance & Rarity

Sourced directly from a historic U.S. military initiative, these optics meet rigorous standards (e.g., environmental durability akin to MIL-spec), ensuring reliability in extreme conditions. Their custom specifications—the asymmetric 30:70 split ratio and the HED diffractive pattern—are not standard catalog offerings. They represent a level of design sophistication and manufacturing precision required for mission-critical defense systems.

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Condition

PRISTINE SURPLUS
USED – ONLY SUBTLE EDGE CHIPS (AS NOTED)
OPTICAL SURFACES: COATING INTACT, GRATING UNDAMAGED
NO MOUNTING HARDWARE OR DOCUMENTATION INCLUDED
PICTURE MAY NOT MATCH PRODUCT

⚠ HANDLING NOTE: These are precision optical components with delicate AR coatings and diffractive structures. Handle only by edges with clean gloves. Never touch optical surfaces. Store in clean, dry environment when not in use. Germanium is a brittle material; handle with care.