Rutile TiO₂ Polarizers

  • Extinction Ratio: 100 000:1
  • 2.2 - 4 µm Wavelength Range
  • Transmits Linearly Polarized Light



GTR5-MIR Mounted in a
PRM1GL10 Rotation Mount

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Rutile Polarizer Beam Path Drawing
Click to Enlarge

Side View of a Rutile Polarizer
Unpolarized Light Enters, S-Polarized Light is Reflected
and Absorbed, P-Polarized Light is Transmitted


  • 100 000:1 Extinction Ratio
  • 2.2 - 4 µm Wavelength Range
  • AR-Coated Entrance and Exit Faces for the Entire Wavelength Range

Our Rutile (TiO2) Polarizers offer extremely pure polarization of light with a 100 000:1 extinction ratio. They are meant for use with lasers in the 2.2 - 4 µm wavelength range and have an air-spaced design. Please note that Rutile Polarizing Prisms are designed to work with well collimated light beams. Divergent beams will produce multiple output beams.

Our Rutile Polarizing Prisms utilize a Glan-Foucault design, with two right-angle rutile prisms spaced slightly apart to create a gap. As rutile is a positively birefringent crystal, as opposed to a negatively birefringent material like calcite, the ordinary, rather than the extraordinary ray, is transmitted. When unpolarized light enters the polarizer, the beam is split into two polarized rays at the internal interface. Due to the difference in refractive indices, no and ne, the ordinary polarization component (p-polarized light) passes straight through the polarizer without deviation, while the extraordinary polarization component (s-polarized light) is deflected by total internal reflection and absorbed by the polarizer housing. The output polarization is parallel with the Polarization Axis line on the polarizer housing.

Our rutile polarizers have λ/4 polished optical faces with a Ø5 mm or Ø8 mm clear aperture. Additionally, the entrance and exit faces are AR-Coated over the entire wavelength range. They include a square aluminum housing with the polarization axis clearly marked. The GTR5 has a 9.6 mm square housing, while the GTR8 has a 15.9 mm square housing.

The GTM5 is compatible with the SM05PM5 and PRM05GL5 mounts, while GTM8 is compatible with the SM1PM10 and PRM1GL10 mounts.

Material TiO2 (Rutile)a
Extinction Ratiob 100 000:1
Wavelength Range 2.2 - 4 µm
Transmission 93% Average within Specified Wavelength Range
Acceptance Angle (Typical) ±2.0°
Beam Deviation <3 arcmin
Surface Quality 20-10 Scratch-Dig
Surface Flatness (@633 nm) λ/4
AR Coating (Entrance and Exit Windows) Ravg < 1% from 2.2 - 4 µm
Clear Aperture Ø5 mm Ø8 mm
Housing Anodized Aluminum
Housing Dimensions (l x w x h) 9.1 mm x 9.5 mm x 9.5 mm 10.7 mm x 15.9 mm x 15.9 mm
Recommended Mounts SM05PM5
  • Click Link for Detailed Specifications on the Substrate
  • The extinction ratio (ER) is the ratio of maximum to minimum transmission of a sufficiently linearly polarized input. When the transmission axis and input polarization are parallel, the transmission is at its maximum; rotate the polarizer by 90° for minimum transmission.

Posted Comments:
Giorgio Guercio  (posted 2023-06-26 09:16:30.83)
Hello, Is it possible to obtain a transmittance spectrum that cover the wavelength range between 1000-2000 nm for the GTR5-MIR device? Best regards
jpolaris  (posted 2023-06-26 02:25:43.0)
Thank you for contacting Thorlabs. GTR5-MIR uses a Rutile (TiO2) substrate, which has a typical transmission of ~70% - 73% within the 1000 nm - 2000 nm range. I have reached out to you directly with extended transmission data for this substrate. More information about Rutile can be found at the following page.
jean-christophe.delagnes  (posted 2016-03-22 21:48:46.147)
Rutile Sellmeier equation for both (o) and (e) wave is the one established by Devore in 1951. This formula is only specified for wavelength in the 0.43 - 1.53 um range while GTR8-MIR is specified for 2.2 - 4 um? How can I estimate the GVD of this polarizer at 3 um (ultrafast application)? Can you update the product page with GVD in the ragne of interest?
besembeson  (posted 2016-03-24 04:35:47.0)
Response from Bweh at Thorlabs USA: That is correct. We will review the plot we have that extends to 5um. I will contact you regarding the GVD around 3um.

Polarizer Selection Guide

Thorlabs offers a diverse range of polarizers, including wire grid, film, calcite, alpha-BBO, rutile, and beamsplitting polarizers. Collectively, our line of wire grid polarizers offers coverage from the visible range to the beginning of the Far-IR range. Our nanoparticle linear film polarizers provide extinction ratios as high as 100 000:1. Alternatively, our other film polarizers offer an affordable solution for polarizing light from the visible to the Near-IR. Next, our beamsplitting polarizers allow for use of the reflected beam, as well as the more completely polarized transmitted beam. Finally, our alpha-BBO (UV), calcite (visible to Near-IR), rutile (Near-IR to Mid-IR), and yttrium orthovanadate (YVO4) (Near-IR to Mid-IR) polarizers each offer an exceptional extinction ratio of 100 000:1 within their respective wavelength ranges.

To explore the available types, wavelength ranges, extinction ratios, transmission, and available sizes for each polarizer category, click More [+] in the appropriate row below.

Wire Grid Polarizers
Film Polarizers
Beamsplitting Polarizers
alpha-BBO Polarizers
Calcite Polarizers
Quartz Polarizers
Magnesium Fluoride Polarizers
Yttrium Orthovanadate (YVO4) Polarizers
Rutile Polarizers
  • Click on the graph icons in this column to view a transmission curve for the corresponding polarizer. Each curve represents one substrate sample or coating run and is not guaranteed.
  • Mounted in a protective box, unthreaded ring, or cylinder.
  • Available unmounted or in an SM05-threaded (0.535"-40) mount that indicates the polarization axis.
  • Available unmounted or in an SM1-threaded (1.035"-40) mount that indicates the polarization axis.
  • PBS519: Average TP:TS > 1000:1
  • Available unmounted or mounted in cubes for cage system compatibility.
  • Calcite's transmittance of light near 350 nm is typically around 75% (see Transmission column).
  • Available unmounted or in an unthreaded Ø1/2" housing.
  • The transmission curves for calcite are valid for linearly polarized light with a polarization axis aligned with the mark on the polarizer's housing.
  • The 1064 nm V coating corresponds to a -C26 suffix in the item number.
  • Available unmounted or mounted in a protective box or unthreaded cylinder that indicates the polarization axis.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
GTR5-MIR Support Documentation
GTR5-MIRMid-IR Rutile Polarizer, Ø5 mm Clear Aperture, 2.2 - 4 µm
GTR8-MIR Support Documentation
GTR8-MIRMid-IR Rutile Polarizer, Ø8 mm Clear Aperture, 2.2 - 4 µm