Unfortunately, this is highly dependent on factors such as absorption and thermal diffusivity, so there is no reliable method for determining when a high PRF laser will damage an optic due to thermal effects.

Absorption is either due to an intrinsic property of the optic or due to surface irregularities; thus LIDT values are only valid for optics meeting or exceeding the surface quality specifications given by a manufacturer. I would like to swap the polarization that is transmitted without rotating the entire cube since the only mount is on the bottom face. Response from Bweh at Thorlabs USA: I will share the extended reflection data with you via email. The highlighted columns in the table below outline the relevant pulse lengths for our specified LIDT values.

Like our Glan-Taylor polarizers, these polarizers are ideal for applications requiring extremely high polarization purity (100,000:1) and high damage thresholds. How sensitive is the extinction ratio of GL15 to the alignment of the crystal? We also offer empty 30 mm cage cubes that are compatible with our line of unmounted beamsplitter cubes.

Rotate the front wheel so that it matches the polarization of your source, and tighten the setscrew using a 0.035" hex key, located on the face to the left of the 2. If the optic was tested at a wavelength other than your operating wavelength, the damage threshold must be scaled appropriately. Please keep in mind that these tests are performed on clean optics, as dirt and contamination can significantly lower the damage threshold of a component. As seen in the drawing and graph below and to the right, the side of the polarizer with the escape window has an FOV that decreases as the wavelength increases (FOV 1). When replacing a polarizer in the mount, be sure to align the engraving on the polarizer with the 0° engraving on the scale.

If your power density is less than the adjusted LIDT of the optic, then the optic should work for your application. When comparing an LIDT specified for a pulsed laser to your laser, it is essential to know the following: LIDT in energy density vs. pulse length and spot size. When comparing an LIDT specified for a pulsed laser to your laser, it is essential to know the following: LIDT in energy density vs. pulse length and spot size. This process is repeated until damage is observed.

The damage threshold is then assigned to be the highest power/energy that the optic can withstand without causing damage. A good rule of thumb is that the damage threshold has an inverse square root relationship with wavelength such that as you move to shorter wavelengths, the damage threshold decreases (i.e., a LIDT of 1 J/cm2 at 1064 nm scales to 0.7 J/cm2 at 532 nm): You now have a wavelength-adjusted energy density, which you will use in the following step.

(5) Placing too much stress on one of the optics in the system (polarizer, lenses, or others), causing stress birefringence. This can be compared to the LIDT values for a WPQ10E-980 polymer zero-order quarter-wave plate, which are 5 W/cm for CW radiation at 810 nm and 5 J/cm2 for a 10 ns pulse at 810 nm. The calculation above assumes a uniform beam intensity profile. 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. Calcite's transmittance of light near 350 nm is typically around 75% (see. These modules absorb light that is not aligned to the transmission axis of the polarizer and are designed for the 500 - 720 nm, 650 - 2000 nm, or 1.5 - 5.0 µm wavelength range.

In CW applications, for instance, damage scales more strongly with absorption in the coating and substrate, which does not necessarily scale well with wavelength. In order to use the specified CW damage threshold of an optic, it is necessary to know the following: Thorlabs expresses LIDT for CW lasers as a linear power density measured in W/cm. This means that both CW and pulsed damage thresholds must be compared to the laser beam to determine whether the optic is suitable for your application.

For reference a Gaussian beam typically has a maximum energy density that is twice that of the 1/e2 beam.

The damage analysis will be carried out on a similar optic (customer's optic will not be damaged).

You must now adjust this energy density to account for hotspots or other nonuniform intensity profiles and roughly calculate a maximum energy density.

For reference, a Gaussian beam typically has a maximum power density that is twice that of the uniform beam (see lower right).
The LIDT for an optic greatly depends on the type of laser you are using. Contact Tech Support for more information. Thank you for contacting Thorlabs.

California - (5) Colorado - (1) Illinois - (1) New Jersey - (1) New Mexico - (1) New York - (1) Texas - (1) Thorlabs, Inc. Anyway, by spatially filtering out this beam, you can reach a 2.10^7 ratio. After exposure, the optic is examined by a microscope (~100X magnification) for any visible damage.

LIDT in linear power density vs. pulse length and spot size. Next, our beamsplitting polarizers allow for use of the reflected beam, as well as the more completely polarized transmitted beam.
For data presented here, a <1 mm beam size was used to measure the LIDT. You could have the freedom to orient the cube as you desire if you consider a combination of the CM1-4ER and the PBS251. My application is very sensitive to the beam displacement, so do you have any other recommendation of polarizer eliminating beam displacement?

These lower thresholds are due to absorption or scattering in the cement or metal coating. The pulsed LIDT of the optic is significantly greater than the energy density of the laser pulse, so individual pulses will not damage the wave plate. These polarizers are manufactured from select portions of the calcite crystal that must pass a laser scattering sensitivity test. I measure an extinction ratio (Pout/Pin for e ray) of 2.10^7, i.e.

Therefore, an adjustment must be applied for the shorter pulse duration of the system under consideration.

Which is the maximum divergence allowed. Newton - (1) Find by state.

Please see the Graphs tab for coating reflectivity data. Testing may result in additional costs or lead times. Calcite polarizers feature a field of view (FOV) that varies with both wavelength and entrance orientation.

Screw the threaded end of the lens tube into the rotation mount as shown in Figure 1.

Hello. In order to use the specified CW damage threshold of an optic, it is necessary to know the following: Thorlabs expresses LIDT for CW lasers as a linear power density measured in W/cm.

In this regime, the LIDT given as an energy density can be applied to any beam diameter; one does not need to compute an adjusted LIDT to adjust for changes in spot size. In our Double Glan-Taylor polarizers, this birefringence causes the selective reflection and absorption of one polarization state of an incident beam and the transmission of the other orthogonal polarization state. A histogram such as that below represents the testing of one BB1-E02 mirror. If your maximum energy density is less than this adjusted LIDT maximum energy density, then the optic should be suitable for your application.

Average linear power density can be calculated using the equation below.

My Thorlabs Products Home / Polarization Optics / Polarizers / Crystal Polarizers / Mounted Glan-Thompson Polarizers, 650 - 1050 nm AR Coating / GTH10M-B GTH10M-B - Mounted Glan-Thompson Calcite Polarizer, 10 mm x 10 mm Clear Aperture, 650 - 1050 nm AR Coating Note: As with all Glan-Thompson polarizers, the maximum optical intensity is limited by the cemented prism interface.

Thorlabs' LIDT testing is done in compliance with ISO/DIS 11254 and ISO 21254 specifications.First, a low-power/energy beam is directed to the optic under test. Fabricated from a single piece of the highest quality optical grade calcite, our beam displacers can be used with wavelengths from 350 nm up to 2.3 μm.

Unfortunately, this is highly dependent on factors such as absorption and thermal diffusivity, so there is no reliable method for determining when a high PRF laser will damage an optic due to thermal effects. The damage analysis will be carried out on a similar optic (customer's optic will not be damaged). Because dust or other particles on the surface of an optic can cause damage at lower thresholds, we recommend keeping surfaces clean and free of debris. As previously stated, pulsed lasers typically induce a different type of damage to the optic than CW lasers. Hello, thank you for contacting Thorlabs. They are designed to displace the horizontal polarization for a variety of wavelength ranges.

Thank you so much for your feedback and for sharing your results with us. While each polarizer is air-spaced within the clear aperture, the prisms composing the polarizer are separated by an epoxied photo-etched spacer that is not designed to withstand high laser powers. The length of these prisms has been chosen to separate the beams by 2.7 mm or 4.0 mm.

There are a variety of possible causes that we could consider: This calculation assumes a uniform beam intensity profile. For reference, a Gaussian beam typically has a maximum power density that is twice that of the uniform beam (see lower right).

The 1064 nm V coating corresponds to a -C26 suffix in the item number. The uncoated polarizers are designed for use in the 350 nm to 2.3 μm range, while coated versions offer Ravg < 1% per surface in the 350 - 700 nm or 650 - 1050 nm wavelength range. After fastening the engagement screw with a 0.028" hex key, the cell can be precisely positioned by turning the actuator at the top of the part with a 0.050" hex key. The average energy density of each pulse is found by dividing the pulse energy by the beam area: As described above, the maximum energy density of a Gaussian beam is about twice the average energy density. These modules absorb light that is not aligned to the transmission axis of the polarizer and are designed for the 500 - 720 nm, 650 - 2000 nm, or 1.5 - 5.0 µm wavelength range. Our calcite polarizers are typically built out of two prisms, as shown in the drawing to the right.

Upon request, we can provide individual test information and a testing certificate. Our Glan-Laser and Glan-Taylor polarizers are designed as polarizer elements that remove the reflected ordinary polarization component of a beam. The number of locations that are damaged at a particular power/energy level is recorded. The pulse length must now be compensated for. Additionally, for highly transparent materials, there is little to no drop in the LIDT with increasing PRF. Keep in mind that this calculation is only used for pulses between 10-9 s and 10-7 s. For pulses between 10-7 s and 10-4 s, the CW LIDT must also be checked before deeming the optic appropriate for your application. For beams with a high PRF both the average and peak powers must be compared to the equivalent CW power.

[2] Roger M. Wood, Laser-Induced Damage of Optical Materials (Institute of Physics Publishing, Philadelphia, PA, 2003). Pulsed lasers with high pulse repetition frequencies (PRF) may behave similarly to CW beams. The mounted GTH5M polarizer has a 1/2" outer diameter and can be conveniently held inside our SM05L10 lens tube. After exposure, the optic is examined by a microscope (~100X magnification) for any visible damage.

Upon request, we can provide individual test information and a testing certificate.

The LIDT for an optic greatly depends on the type of laser you are using.