Products


50
Yes
detail
detail
None
1
10
Search Products
/product-search/
Detail
Filter

Upload PDF Datasheet at here:

Product Types

Markets

Prisms & Rhombs

It’s often necessary to alter or manipulate the source’s polarization. For example, a reflective phase retarder converts linear to circular polarization and improves the laser cutting quality. (For reflective phase retarders, please see Phase Retarders.) However, most polarization altering devices -- the reflective phase retarder and waveplates -- are very wavelength sensitive and offer only narrowband, or single wavelength operation.

The Fresnel prisms and rhombs described on this page utilize the principle that when light undergoes total internal reflection, there is a relative phase change between the s and p polarization components. This effect is only weakly dependent on wavelength (Figure 1). Thus, these components are ideal for those working at either multiple distinct wavelengths or with broadband sources in the 8 to 12 µm region.

By manipulating the rhomb’s geometry, devices which produce quarter-wave, half-wave, or virtually any required retardation can be constructed. Please contact a II-VI sales representative with your design requirements.

Prism Type

Quarter-Wave Prism
converts linear into circular polarization, and turns the beam path

 

 

 

Quarter-Wave Rhomb
produces an output beam which is parallel, but displaced from, the input

 

 

 

Half-Wave Rhomb
changes the polarization's orientation for a linearly polarized input. The output polarization orientation is varied by rotating the rhomb around the optical axis. The output beam is parallel to, but displaced from, the input beam.

Reflective Phase Retarders

Metal cutting and other critical laser operations are sensitive to any variation in kerf width or cross-section. The kerf’s quality depends on the polarization orientation relative to the cut direction. This is illustrated in Figure 1.

Current theory suggests that the assumption of a focused beam striking the work piece at normal incidence is only true at the cut’s beginning. Once the kerf forms, the beam encounters metal at some large angle of incidence, Θ, as shown in Figure 2. Light which is s-polarized with reference to such a surface is reflected much more than light which is p-polarized, leading to the difference in cut quality.

Introducing a quarter-wave (90°) reflective phase retarder into the beam delivery path eliminates kerf variations by converting linear polarization to circular polarization. Circular polarization consists of equal amounts of s-polarization and p-polarization for any beam orientation, therefore all axes encounter the same composition of polarization, and material is removed uniformly regardless of cut direction. This is illustrated in the photos below.

A linearly polarized beam is oriented so that the plane of polarization is 45° to the plane of incidence and strikes the RPR at 45° to the normal, as shown in Figure 3. The reflected beam is circularly polarized.

The substrate choice depends upon the power level at which the laser operates. Alternate substrates, including water-cooled copper, are available. Eighth-wave and sixteenth-wave RPR designs, and designs for peak wavelengths other than 10.6µm are also available. Please contact a II-VI sales

The substrate choice depends upon the power level at which the laser operates. Alternate substrates, including water-cooled copper, are available. Eighth-wave and sixteenth-wave RPR designs, and designs for peak wavelengths other than 10.6µm are also available. Please contact a II-VI sales representative to obtain a quotation.

Ragged Cutproduced by linearly polarized light Clean Cutproduced by circularly polarized light

 

Specifications

Specifications
Standards
Dimensional Tolerances
Diameter: +0.000”-0.005”
Thickness: +/-0.010”
Parallelism
<= 3 arc minutes
Clear Aperture (polished)
90% of diameter
Surface Figure (power/irregularity) at 0.63µm
<=2 fringes/0.5 fringe
Scratch-Dig
10-5
Reflectivity @ 10.6µm
>= 98%
Phase Retardation for 10.6µm @ 45º
90º +/- 3º
Ellipticity Ratio
0.90-1.11

Part Information

Part #
Description
Diameter
(inches)
Diameter
(mm)
Edge
Thickness
(inches)
Edge
Thickness
(mm)
Phase Shift
@ 10.6µm
(degrees)
498237
Si
1.5
38.1
0.16
4.06
90+/-6
893833
Si
2.0
50.8
0.20
5.08
90+/-2
582132
Si
2.0
50.8
0.20
5.08
90+/-2
592353
Si
2.0
50.8
0.375
9.53
90+/-6
102719
Si
2.0
50.8
0.170
5
90+/-2
969917
Si
2.0
50.8
0.40
10.16
90+/-6
772930
Si
2.677
68
0.80
20.32
90+/-1
697768
Si
3.0
76.2
0.236
6
90+/-6
224094
Si
3.0
76.2
0.25
6.35
90+/-6
390686
Cu
1.5
38.1
0.25
6.35
90+/-6
666269
Cu
1.969
50
0.394
10
90+/-6
832944
Cu
2.25
57.15
0.394
10
90+/-2
488199
Cu-WC*
2.25
57.15
1.25
31.75
90+/-6
800102
Cu
2.362
60
0.394
10
90+/-2
634413
Cu
2.362
60
0.591
15
90+/-2
748680
Cu
3.0
76.2
0.50
12.7
90+/-6
744069
Cu
3.0
76.2
0.591
15
90+/-2
*Cu-WC: water-cooled copper 
Contact a II-VI sales representative for exact specifications.
Thin-Film Polarizers

Thin Film Polarizers (TFPs) can split a laser beam into two parts with orthogonal polarizations. Conversely, TFPs can be used to combine two beams with orthogonal polarizations. TFPs consist of a coated plate, which is oriented at Brewster’s angle with respect to the incoming beam. The thin-film coating serves to enhance the beam’s s-polarized reflectivity, while maintaining the p-polarized component’s high transmission

Below is a TFP schematic splitting an unpolarized input beam into s-polarized and p-polarized components:

TFP schematic splitting The standard TFP reflects the s-polarized beam at Brewster’s angle; for those applications which require a 90° separation between the s-polarized and p-polarized beams, our optional turning mirror can be added.

II-VI offers both ZnSe and Ge TFPs. II-VI can design TFP coatings for wavelengths other than 10.6 microns, and formulations for other materials to meet your requirements. Contact a II-VI sales representative to discuss.

Waveplates

Waveplates use a phenomenon known as birefringence to alter the incoming laser beam polarization state. The most common waveplate uses are for turning linearly polarized light into circularly polarized light (quarter-wave plates), and to rotate the polarization plane of a linearly polarized source (half-wave plates).

II-VI manufactures both multiple order and zero order waveplates. Zero order waveplates have the dual advantage of being less sensitive to changes in operating temperature and input wavelength.

Applications

  • Converting linear to circular polarization
  • Rotating the polarization plane

Features

  • High-power handling
  • Low-insertion loss
  • Apertures up to 1.0”
  • Visible transmission for easy alignment
  • Rotating mounts available
Prisms & Rhombs
It’s often necessary to alter or manipulate the source’s polarization. For example, a reflective phase retarder converts linear to circular polarization and improves the laser cutting quality. (For reflective phase retarders, please see Phase ... Read More
Reflective Phase Retarders
Metal cutting and other critical laser operations are sensitive to any variation in kerf width or cross-section. The kerf’s quality depends on the polarization orientation relative to the cut direction. This is illustrated in Figure 1. ... Read More
Thin-Film Polarizers
Thin Film Polarizers (TFPs) can split a laser beam into two parts with orthogonal polarizations. Conversely, TFPs can be used to combine two beams with orthogonal polarizations. TFPs consist of a coated plate, which is oriented at Brewster’s ang... Read More
Waveplates
Waveplates use a phenomenon known as birefringence to alter the incoming laser beam polarization state. The most common waveplate uses are for turning linearly polarized light into circularly polarized light (quarter-wave plates), and to rotate th... Read More
Share This
X