647 nm laser mirror dielectric HR coating

Product Description

High-Reflectivity 647 nm Laser Mirror – Surplus from US Defense Lab

This is a high-quality, flat circular optic measuring 75 mm in diameter and 9.25 mm thick, sourced directly from a US Defense laboratory. The substrate is precision optical glass: N-BK7 borosilicate crown glass, known for excellent transmission in the visible spectrum and high laser damage thresholds suitable for demanding applications .

Borosilicate crown glass (N-BK7) is a preferred material for precision optics due to its exceptional homogeneity, low bubble and inclusion content, and stable mechanical properties. It offers excellent transmission from 350 nm to 2.1 μm, making it ideal for visible and near-infrared laser applications .

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Key Specifications

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Coating Technology & Performance

Multilayer Dielectric Coatings:
Dielectric mirrors consist of alternating layers of high and low refractive index materials (such as Ta₂O₅, TiO₂ for high index; SiO₂ for low index) deposited via techniques like ion beam sputtering . These layers create constructive interference for the target wavelength, resulting in extremely high reflectivity without the absorption losses associated with metallic coatings.

Key Characteristics of This Mirror:

• >95% Reflectivity at 647 nm: Optimized for the 647 nm krypton-argon laser line, commonly used in scientific and microscopy applications

• 45° Angle of Incidence: Configured for folded beam paths, beam steering, and sampling applications

• s-Polarization Optimized: Designed for polarized laser sources, maximizing reflection efficiency

• AR-Coated Back Surface: Reduces unwanted reflections and prevents ghosting or interference in optical systems

Polarization Effects:
At non-normal incidence, the reflectance of dielectric mirrors becomes polarization-dependent . As the angle of incidence increases, the high-reflection (HR) range shifts to shorter wavelengths, with the effect differing for s- and p-polarized light. This mirror is specifically optimized for 45° and s-polarization, ensuring maximum performance at the specified wavelength.

Partial Reflector Function:
With ≥95% reflectivity, this mirror allows ~5% transmission, making it useful for beam monitoring applications where a small sample of the main beam is needed for power measurement or alignment verification.

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Substrate Advantages – N-BK7

N-BK7 is the most common optical glass for general-purpose precision optics, offering an excellent combination of optical performance, mechanical durability, and cost-effectiveness . Its high homogeneity ensures minimal wavefront distortion, critical for laser applications.

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Applications

Laser Beam Steering and Folding:
Ideal for directing laser beams in complex optical paths, whether in research setups, industrial systems, or defense prototypes.

Beam Sampling and Monitoring:
The ~5% transmission enables beam sampling for:

• Power monitoring and feedback control

• Beam profiling and alignment verification

• Wavelength monitoring with spectrometers

Krypton-Argon Laser Systems:
Specifically optimized for the 647 nm line (Kr-Ar lasers), common in:

• Fluorescence microscopy (e.g., excitation of Alexa Fluor 647 dyes)

• Flow cytometry and cell sorting

• Raman spectroscopy

Intelligence, Surveillance, and Reconnaissance (ISR) :
Originally used in advanced DoD electro-optical systems, this mirror is suitable for:

• Aerial and satellite imaging systems

• Target tracking and designation

• Multi-spectral sensors

Spectroscopic Analysis:
Perfect for laser-based spectroscopy where clean beam steering and minimal stray light are essential.

Bioaerosol Detection:
Defense R&D applications often use 647 nm lasers for fluorescence excitation in biological agent detection systems.

Custom Optical Experiments:

• Microscopy illumination paths

• Laser alignment systems

• Interferometry

• Optical communications prototypes

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Defense Laboratory Heritage

This mirror’s provenance from a US Defense Laboratory specializing in advanced electro-optical systems adds significant value. These labs pioneer technologies for:

• Airborne laser systems

• Advanced imaging and surveillance

• Directed energy research

• Chemical and biological detection

Owning this optic connects you to cutting-edge defense technology—a tangible piece of research-grade instrumentation.

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Condition

GREAT – OPTICALLY SOUND AND READY FOR INTEGRATION
NO CHIPS, SCRATCHES, OR COATING DELAMINATION
COATING UNIFORM AND INTACT ON BOTH SURFACES
EDGE MARKINGS CLEARLY LEGIBLE
STORED IN PROTECTIVE ENVIRONMENT

⚠ HANDLING NOTE: This is a precision optical component with delicate dielectric coatings. Handle only by edges with clean gloves. Never touch coated surfaces. Store in clean, dry environment when not in use.