Beam Splitter (PBS)

Overview of BeamSplitter

The composition of a polarizing beam splitter: It is typically made by cementing or optically contacting the hypotenuse sides of two right-angle prisms, with a polarizing beam splitting film applied to the hypotenuse. P-polarized light in the incident light is transmitted, while S-polarized light is reflected. Anti-reflective coatings are generally applied to all the incident and exit surfaces of the light beams.

Features of BeamSplitter

The polarizing beam splitter divides incident light into two orthogonally polarized components:

• Transmitted light (T): p-polarized

• Reflected light (R): s-polarized

Working Mechanism:
When light enters the right-angle prism perpendicularly through its hypotenuse face, the embedded multilayer coating induces Brewster's angle refraction at dielectric interfaces

Through optimized thin-film design:

p-polarized light experiences near-zero reflection loss (transmittance >90%) due to Brewster angle conditions

s-polarized light undergoes cumulative reflections across multiple coating layers, achieving >99.5% reflectance

Incident Light Requirements:

No polarization restriction: Both natural light and pre-polarized light can be effectively split into orthogonal components

Specifications of BeamSplitter

Catalog of BeamSplitter

Applications of BeamSplitter

1. Multiphoton Imaging

Optical Isolation: PBS combined with a quarter-wave plate (QWP) creates optical isolators to control light propagation paths. This setup converts linearly polarized light to circularly polarized light, preventing back-reflections from disrupting the imaging system.

Intensity Modulation: By integrating PBS with a half-wave plate (HWP), rotating the HWP adjusts the polarization angle of incident light, enabling precise control of light intensity and power output.

2. Laser Interferometry

Beam Splitting and Interference: In Michelson interferometers, PBS splits laser light into two orthogonal polarized beams (P and S). One beam reflects off a fixed mirror, while the other reflects off a moving mirror. The recombination of these beams produces interference patterns with a 90° phase shift, allowing precise measurement of displacement via photodetectors.

Heterodyne Interferometry: PBS separates dual-frequency laser beams for applications requiring Doppler-shift detection, enhancing measurement accuracy in aerospace and precision manufacturing.

3. Optical Instrumentation

Error Correction in CNC Machines: PBS-based interferometers are critical for calibrating CNC machines, ensuring micron-level precision by detecting mechanical deviations.

3D Imaging: In stereoscopic displays, PBS separates orthogonal P/S polarized light for left/right eye channels, enabling immersive 3D effects when paired with polarized glasses.

4. Broadband and Narrowband Applications

Broadband PBS (420–1600 nm): Suitable for systems requiring wide spectral coverage, such as fluorescence microscopy and tunable lasers. These PBS maintain high extinction ratios (>1000:1) and low absorption losses across broad wavelengths.

Narrowband PBS: Optimized for specific wavelengths (e.g., 632.8 nm or 1700 nm), these components are used in waveplates and fiber-optic systems to convert linear to circular polarization via birefringent crystals (e.g., quartz or calcite).