Rare Large-Aperture Precision Dielectric Laser Mirror – 100mm Fused Quartz High Reflector

This is an exceptional 100mm diameter precision dielectric mirror on a fused quartz substrate, optimized as a maximum reflector (HR) at 514.5 nm (5145 Å) – the iconic bright green line of argon-ion lasers. The edge arrow points to the coated high-reflection surface, which exhibits the classic yellowish-orange dielectric appearance under white light (complementary color to its strong green reflection).

Originally designed for intracavity use in high-power argon-ion laser resonators (likely from a large-frame system like Coherent Innova or Spectra-Physics models), this optic features elite specifications rarely seen in surplus:

Key Specifications (Etched on Edge & Measured):

• Diameter: 100 mm (±0.25 mm typical)

• Thickness: 15 mm

• Substrate: High-purity Fused Quartz (low absorption, excellent thermal stability, UV-Vis-NIR transmission)

• Surface Flatness: λ/20 (extremely high precision, typically @ 632.8 nm)

• Parallelism/Wedge: < 0.00012 radians (≈ 25 arcseconds – outstanding for minimal beam deviation)

• Coating: Multilayer dielectric HR on one side; R_max at 514.5 nm

• Angle of Incidence: Optimized for θ = 15° (unpolarized light – suggesting folded/resonator geometry)

• Transmission Bands: T > 70% (0.3–1.44 μm range noted), T > 30% (0.6–1.0 μm) – high transmission outside reflection band

• Clear Aperture: >90% (full diameter usable)

Dielectric coatings deliver >99.9% reflectivity, ultra-low absorption/loss, and high laser damage threshold – far superior to metallic mirrors for cavity applications where efficiency and stability are critical.

Applications:

• Primary: Intracavity high reflector in argon-ion laser systems (air-cooled or water-cooled frame-style heads) for multi-watt green output

• Beam steering/mixing at low 15° AOI in visible laser setups

• Precision reference flat (uncoated back side is polished to same high standards – ideal for interferometry, alignment, or optical testing)

• Custom 514–520 nm laser systems (e.g., pumping dye lasers, spectroscopy)

• Historical/scientific: Restoring vintage argon-ion lasers used in groundbreaking research (Raman spectroscopy, holography, early confocal microscopy, laser light shows, medical applications like ophthalmology)

Argon-ion lasers were scientific workhorses from the 1970s–2000s, powering advances in physics, biology, and entertainment. This large aperture reduces power density and thermal lensing in high-power cavities, enabling stable TEM₀₀ operation.

Condition:

Excellent gently used surplus condition .Coating intact and vibrant; no scratches, digs, or delamination visible. Minor edge handling marks possible (normal for lab optics). Photos show actual item.

This is a standout, museum-quality piece for serious optical engineers, laser enthusiasts, university labs, collectors of vintage scientific instruments, or anyone needing a ultra-precision large flat. Far superior to generic mirrors –