Depolarizing
Plate Beamsplitters

Beamsplitters are optical components that split light in two directions. For example they are typically used in interferometers in order for a single beam to interfere with itself. There are generally several different types of beamsplitters: plate, cube, pellicle and polka dot beamsplitters. A standard beamsplitter splits a beam by percentage of intensity, such as 50% transmission and 50% reflection or 30% transmission and 70% reflection. Non-polarizing beamsplitters are specifically controlled not to alter the S and P polarization states of the incoming light. Polarizing beamsplitters will transmit P polarized light and reflect S polarized light, allowing the users to add polarized light into a optical system. Dichroic beamsplitters split light by wavelength and commonly used in fluorescence application to separate excitation and emission path.

Although non-polarizing beamsplitters are designed not to alter the S and P polarization states of the incoming light, they are still sensitive to polarized light, that means there will still be some polarization effects if non-polarizing beamsplitters are given the randomly polarized input light. However our depolarizing beamsplitters will be not sensitive to polarization of the incident beam, the difference in reflection and transmission for S- and P-pol. is less than 5%, or there isn’t even any difference in in reflection and transmission for S- and P-pol at the certain design wavelengths. Please check the following graphs for your references.

Paralight Optics offers a wide range of optical beamsplitters. Our plate beamsplitters have a coated front surface that determines the beam splitting ratio while the back surface is wedged and AR coated in order to minimize ghosting and interference effects. Our cube beamsplitters are available in polarizing or non-polarizing models. Pellicle beamsplitters provide excellent wavefront transmission properties while eliminating beam offset and ghosting. Dichroic beamsplitters exhibit beamsplitting properties that are wavelength dependent. They are useful for combining / splitting laser beams of different color.

Features:

Coatings:

All Dielectric Coatings

Optical Performance:

T/R = 50:50, |Rs-Rp| < 5%

Laser Damage Quantification:

High Damage Threshold

Design Options:

Custom Design Available

Common Specifications:

pro-related-ico — Reference Drawing for

Depolarizing Plate Beamsplitter

Note: For the substrate with a 1.5 index of refraction and a 45° AOI, beam shift distance (d) can be approximated using the left equation.
Polarization Relationship: |Rs-Rp| < 5%, |Ts-Tp| < 5% at the certain design wavelengths.

Parameters

Ranges & Tolerances

Type

Depolarizing Plate Beamsplitter
Dimension Tolerance

Precison: +0.00/-0.20 mm | High Precision: +0.00/-0.1 mm
Thickness Tolerance

Precison: +/-0.20 mm | High Precision: +/-0.1 mm
Surface Quality (Scratch-Dig)

Typical: 60-40 | Precision: 40-20
Surface Flatness (Plano Side)

< λ/4 @632.8 nm
Beam Deviation

< 3 arcmin
Chamfer

Protected < 0.5mm X 45°
Split Ratio (R:T) Tolerance

± 5%
Polarization Relationship

|Rs-Rp| < 5% (45° AOI)
Clear Aperture

> 90%
Coating (AOI=45°)

Depolarizing beamsplitter dielectric coating on the front surface, AR coating on the back surface.
Damage Threshold

>3 J/cm², 20ns, 20Hz, @1064nm