Brewster Window Plate

The Brewster window plate is designed to present the original profile when positioned at the Brewster Angle (55.57°). UItraopto Precision Optics Co. Ltd. Optoelectronics Brewster window sheets have laser-grade surface quality and parallelism, which can limit the wavefront distortion of the transmission to λ/10. When used at 55.57°, these Windows minimize the loss of p-polarized light, especially suitable for use in laser cavities and applications that generate linearly polarized light.

A Brewster window is a special optical element whose core function is to achieve efficient transmission of light of a specific polarization state at a specific Angle (Brewster Angle) while reflecting light of another polarization state. It works based on Brewster's Angle law: Polarization control: In gas lasers (such as He-Ne lasers) and solid-state lasers, the Brewster window acts as the end mirror or window of the resonator, gradually filtering out S-polarized light through multiple reflections and transmissions, ultimately outputting high-purity p-polarized laser, improving beam quality and efficiency.

UItraopto Precision Optics Co. Ltd. Optoelectronics can stably provide this type of product through precise control of polishing, coating and bonding processes, and accepts custom Brewster window sheets of various specifications.

Reduce polarized light loss

The original   profile is presented at 55.57°

Suitable for use  within a laser cavity

Ultraopto’s Brewster Window Plate is a high-precision optical component engineered for polarization control and low-loss light transmission, serving as a core part in laser resonators, high-power laser systems and precision optical measurement setups. Designed to operate at the standard Brewster angle (55°32'), this specialized window plate enables zero reflection loss for P-polarized light while reflecting approximately 20% of S-polarized light, effectively purifying the polarization state of incident light without the need for additional polarizing elements, making it an efficient and stable polarization control solution for laser cavities and optical systems requiring pure linear polarization. Crafted from premium optical materials including K9 glass and UV fused silica, our Brewster Window Plate is manufactured with ultra-precise grinding and polishing processes, achieving superior surface quality with a 20/10 scratch-dig rating and tight parallelism control below 10 arc seconds, ensuring minimal wavefront distortion (≤λ/10 @633nm) and consistent optical performance across the entire clear aperture (>90%).

The Brewster Window Plate features an uncoated design on the incident surface to leverage the inherent Brewster angle effect, while the exit surface can be optionally coated with anti-reflection (AR) coatings to further reduce residual reflection loss and enhance overall light transmittance. With a high laser-induced damage threshold (LIDT >20J/cm² @1064nm, 20ns, 20Hz), our product can withstand high-energy pulse laser irradiation without coating degradation or structural damage, ensuring long-term stable operation in demanding high-power laser applications. We implement strict dimensional tolerance control (+0.0/-0.2mm for size, ±0.2mm for thickness) and offer protective chamfers (<0.5mm×45°) to prevent edge chipping and improve mechanical durability, making the window plate suitable for both laboratory precision setups and industrial laser systems. The fused silica variant exhibits excellent UV transmittance and thermal stability, while the K9 glass option provides cost-effective performance for visible and near-infrared applications, catering to diverse optical system requirements.

Ultraopto’s Brewster Window Plate is widely applied in professional optical fields that demand polarization control and low-loss light transmission, including laser resonators where it acts as a built-in polarizer to generate polarized laser output and reduce intracavity losses, and high-power laser systems for beam polarization purification and stray light reduction. In precision optical measurement, it enables accurate polarization-dependent testing and analysis of optical materials and components, while in scientific research laboratories, it serves as a key component in polarization optics experiments and laser-based research setups. Additionally, the window plate is used in industrial laser processing equipment, optical communication systems and polarization-sensitive imaging devices, providing reliable polarization control and low-loss light transmission for enhanced system performance. Its robust design and excellent environmental adaptability also make it suitable for harsh industrial environments and long-term continuous operation.

As a leading manufacturer of precision optical components, Ultraopto offers fully customized Brewster Window Plate solutions to meet your unique polarization control requirements. Our professional R&D and engineering team can tailor the substrate material (K9 glass, UV fused silica), dimensions, thickness, surface quality and optional AR coatings to match your specific optical system design. We also provide custom Brewster angle calibration and wavefront distortion optimization for ultra-high precision applications, with ultra-strict tolerance control for critical parameters such as parallelism and surface flatness. 

All custom Brewster Window Plate orders undergo multi-stage strict optical performance testing and quality inspection, including wavefront distortion measurement, LIDT testing, polarization separation efficiency verification and dimensional accuracy inspection, with a detailed quality inspection report provided to ensure the final product fully complies with your design specifications and application needs. Backed by advanced optical processing technology, rich experience in polarization optics and a complete quality control system, Ultraopto ensures stable batch supply capacity and consistent product quality, providing global customers with high-quality Brewster Window Plate products and one-stop optical solutions. For more detailed technical parameters, product quotation information or custom design solutions for our Ultraopto Brewster Window Plate, please contact our professional sales and technical team through the official website, and we will provide you with efficient, personalized and professional optical solutions to support the development and optimization of your high-precision optical systems.