Beamsplitters Selection Guide

Beamsplitters Selection Guide: Types, Applications, and Key Criteria

Beamsplitters are vital optical components in countless systems—from high-end scientific instruments to everyday imaging devices. Whether you’re designing an interferometer, fluorescence system, or beam combining setup, selecting the right beamsplitter is essential for optimal performance.

This Beamsplitters Selection Guide outlines the core types of beamsplitters, explains how they work, and provides practical advice for choosing the best one for your application.

What Is a Beamsplitter?

A beamsplitter is an optical device designed to divide a beam of light into two separate paths—one transmitted and one reflected. This is usually done by applying a thin-film coating on a glass substrate and angling the element relative to the incoming light. In many systems, beamsplitters can also combine two beams into one.

How Beamsplitting Works

1. Intensity-Based Beamsplitting

A partial reflective coating determines the reflection-to-transmission (R/T) ratio, such as 50:50, 70:30, or 60:40. This method is commonly used for general-purpose beam division.

2. Wavelength-Based Beamsplitting (Dichroic)

Dichroic mirrors reflect specific wavelengths and transmit others.

Hot mirrors reflect IR light.
Cold mirrors reflect visible light and transmit IR.

These are ideal for applications like fluorescence microscopy or thermal management.

3. Polarization-Based Beamsplitting

Polarizing beamsplitters separate light into S- and P-polarizations.
Non-polarizing beamsplitters (NPBS) are designed to maintain polarization state, useful in broadband applications.

Types of Beamsplitters

This guide summarizes the major form factors and their respective pros and cons.

Type	Description	Advantages	Limitations
Plate Beamsplitters	Flat coated optical substrates	Easy integration, low cost	Beam offset, ghost reflection
Cube Beamsplitters	Bonded right-angle prisms	No transmitted beam offset, durable	Higher cost, size restrictions
Polarizing Beamsplitters	Dielectric coating on cube or plate	Clean polarization separation	Cube preferred for broadband
Non-Polarizing Beamsplitters	Dielectric or hybrid coatings	Maintains polarization	Metallic coatings add absorption
Dichroic Mirrors	Thin-film coated plates or cubes	Sharp spectral filtering	Cube design widens transition band
Transmission Gratings & Polka Dots	Specialized patterned coatings	Useful for spectroscopy	Less common in standard systems

Where Beamsplitters Are Used

Beamsplitters play an important role in many optical systems:

Application	Beamsplitter Function
Interferometry	Splits light to measure interference (e.g., Michelson interferometer)
Fluorescence Imaging	Dichroic mirrors separate excitation and emission light
Machine Vision	Enables coaxial illumination using plate beamsplitters
Sensor Protection	Cold mirrors block thermal IR to protect detectors
Lighting Design	Dichroic filters adjust color temperature in illumination systems

Beamsplitters Selection Guide: Key Criteria

When selecting a beamsplitter, consider these key factors:

1. Application Purpose

Are you combining beams, dividing intensity, or separating wavelengths? This defines the starting point for your selection.

2. Spectral Requirements

Match the beamsplitter’s coating and substrate to your operational wavelength range—UV, visible, NIR, or IR.

3. Source Compatibility

Use high-damage-threshold coatings for laser applications.
Dielectric coatings are ideal for low-power or incoherent sources.

4. R/T Ratio

Choose based on how much light you want reflected vs. transmitted (e.g., 50:50 for equal splitting, 90:10 for diagnostics).

5. Polarization Handling

Determine if polarization must be preserved, separated, or controlled.

6. Mechanical Constraints

Cube beamsplitters are better for compact systems.
Plate beamsplitters offer more flexibility for open setups.

Tailored Beamsplitter Solutions from Shanghai Optics

Shanghai Optics offers a wide selection of optical beamsplitters, including:

Standard designs: Plate, cube, polarizing, non-polarizing, dichroic
Advanced options: Hot/cold mirrors, polka dot types, and transmission gratings
Fully customized solutions: Designed to meet unique optical, mechanical, and environmental needs

From biomedical optics to aerospace imaging, our team will help you select or develop the optimal beamsplitter for your exact application.

Contact Shanghai Optics today for more information or to place your initial order.