dichroic beamsplitter HR 532nm AR 633nm fused silica

Product Description

High-Precision 75mm Dichroic Beamsplitter – HR 532nm / AR 633nm – Fused Silica Substrate (Surplus from US Defense Research Lab)

Elevate your laser optics setup with this premium plano-plano dichroic beamsplitter, sourced directly from a US Defense Research Laboratory. Measuring 75mm in diameter and 10mm thick, this optic features a robust UV-grade fused silica substrate, renowned for its exceptional thermal stability, low expansion coefficient, and high transmission across visible and near-IR wavelengths. Fused silica ensures durability in demanding environments, making it ideal for high-power applications without risking thermal distortion or damage.

Dichroic beamsplitters of this type are essential components in laser systems where precise wavelength separation is required. They are designed to reflect one wavelength band while transmitting another, typically at a 45° angle of incidence . This optic’s combination of a narrowband high-reflection coating and a broadband anti-reflection coating makes it exceptionally versatile for Nd:YAG harmonic separation and visible alignment beam management.

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Key Specifications

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Material Advantages – UV-Grade Fused Silica

UV-grade fused silica offers exceptional properties for precision laser optics :

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Coating Technology & Performance

Front Surface: HR @ 532 nm (>99%)

• Multi-layer dielectric coating designed for maximum reflectivity at the 532 nm green wavelength (second harmonic of Nd:YAG)

• 99% reflectivity ensures minimal loss in beam steering applications

• Optimized for 45° angle of incidence

• Hard, durable coating resistant to laser damage and environmental factors

Back Surface: AR @ 633 nm (<0.5%)

• Broadband anti-reflection coating minimizes reflections at the 633 nm HeNe laser line

• <0.5% reflectivity reduces ghosting and interference effects

• Ensures clean transmission of visible alignment beams

• AR coating on the second surface is a standard feature of high-quality harmonic beamsplitters

Dielectric Coating Advantages:

• Higher reflectivity than metallic coatings (99%+ vs. 90-96%)

• Lower absorption – reduced heating in high-power applications

• Higher laser damage threshold – suitable for demanding laser systems

• Environmentally stable – resistant to humidity and cleaning

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Primary Application: Harmonic Separation in Nd:YAG Laser Systems

This dichroic acts as a harmonic separator in frequency-doubling laser systems, such as Nd:YAG setups . It reflects the 532 nm second harmonic (green) while transmitting the 1064 nm fundamental (IR) and a co-aligned 633 nm HeNe pilot beam for safe, visible alignment. The beam enters at a typical 45° angle on the HR side, splitting wavelengths efficiently with minimal loss .

Thorlabs notes that harmonic beamsplitters like this are “designed to separate the harmonics of light from Nd:YAG laser sources” and feature a “beamsplitter coating on the front surface” with a back surface “antireflection (AR) V-coated for the transmitted wavelength” . The edge markings ensure proper orientation, as the arrow indicates the recommended propagation direction .

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Applications

Defense & Aerospace:

• Beam combining/separation in laser rangefinders, target designators, or directed energy systems

• Precise wavelength control in military-grade laser systems

• Compatible with the demanding environments of defense applications

Scientific Research:

• Spectroscopy and Raman systems requiring separation of excitation (532nm) from signal wavelengths

• Optical trapping and manipulation experiments

• Quantum optics and atomic physics setups

Medical & Industrial Lasers:

• Frequency-doubled Nd:YAG for dermatology, ophthalmology, or materials processing

• HeNe alignment for setup accuracy in surgical and industrial systems

• Flow cytometry and cell sorting with 532nm excitation

Custom Optics Builds:

• Integrate into prototypes for photonics, metrology, or high-power laser R&D

• Beam combining for multi-wavelength systems

• Alignment setups requiring visible beam transmission through IR optics

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Condition & Provenance

This surplus gem from a defense lab offers lab-tested reliability at a fraction of new cost – perfect for researchers, engineers, or hobbyists building advanced optical systems.

⚠ 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.