Non-Polarizing Cube Beamsplitters (1100 - 1600 nm)
![](https://www.thorlabs.com/Images/GuideImages/6208_BeamCubes_6.jpg)
- Beamsplitter Coating for 1100 - 1600 nm
- 10:90, 30:70, 50:50, 70:30, or 90:10 (R:T) Split Ratio
- AR Coating on Both Input and Output Faces
BS009
5 mm
BS006
1/2"
Engravings Mark the Direction
of Light Propagation
BS024
1"
BS033
2"
1" Beamsplitter Cube Mounted Directly to Breadboard Using BSH1 Prism Mount
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General Specifications | ||
---|---|---|
Wavelength Range | 1100 - 1600 nm | |
AR Coating (All Four Surfaces, Click for Plot) |
Ravg < 0.5% at 0° AOI from 1100 - 1600 nm |
|
Substrate Material | N-BK7a | |
Dimensional Tolerance | +0.0 / -0.2 mm | |
Reflected Beam Deviation | 90° ± 5 arcmin | |
Surface Quality | 40-20 Scratch-Dig |
![](https://www.thorlabs.com/images/TabImages/Cage_Prism_Mount_A5-200.jpg)
Click to Enlarge
1" Beamsplitter Cube Shown in C6WR Cage Cube with B4CRP Rotation Platform and B6C Clamp
(Refer to the BS Cube Mounting Tab for Other Options)
![Beamsplitter Cube](https://www.thorlabs.com/images/TabImages/Beamsplitter_Cube_D6-259.gif)
Cube Beamsplitter Diagram (Coating and Cement Layer Not to Scale)
Features
- Broadband AR-Coated Faces for 1100 - 1600 nm
- Broadband Beamsplitter Coating on Internal Diagonal Surface
- 10:90, 30:70, 50:50, 70:30, or 90:10 (R:T) Split Ratio
- Sizes from 5 mm to 2" (See Below for Details)
- N-BK7 Substrate
Thorlabs' non-polarizing beamsplitter cubes are offered here with broadband AR and beamsplitter coatings designed for 1100 - 1600 nm. These cubes provide a 10:90, 30:70, 50:50, 70:30, or 90:10 beamsplitting ratio with a minimal dependence on the polarization of the incident light (see the tables below for the polarization split ratio tolerances).
Each cube is fabricated from N-BK7 and designed for minimal beam offset. A single reflecting surface also avoids ghost images. The dielectric beamsplitter coating is applied to the hypotenuse of one of the two prisms that make up the cube. Then, cement is used to bind the two prism halves together. These cubes are engraved with arrows that indicate the direction in which the beam is incident on the beamsplitter coating layer, as shown in the diagram to the right. Although light can enter through any of the other AR-coated surfaces, specifications are guaranteed when light is first incident on the side of the beamsplitter coating; see the diagram to the right.
Please refer to the BS Cube Mounting tab above for information on mounting options and compatibility. Alternatively, we offer mounted 1" non-polarizing beamsplitter cubes and 20 mm non-polarizing beamsplitter cubes. The 1" cubes are mounted inside 30 mm cage compatible cubes, each of which features four SM1-threaded (1.035"-40) access ports, while the 20 mm cubes are mounted within 16 mm cage compatible cubes, each of which features four SM05-threaded (0.535"-40) access ports. Additionally, Thorlabs offers pellicle beamsplitters (cube mounted and ring mounted) and plate beamsplitters. For a direct comparison of the performance of our non-polarizing beamsplitter cube, plate, and pellicle at 633 nm, see the Lab Facts tab.
Non-Polarizing Cube Beamsplitters |
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Visible (400 - 700 nm) Beamsplitters |
NIR (700 - 1100 nm) Beamsplitters |
IR (1100 - 1600 nm) Beamsplitters |
Mounted Cube Beamsplitters |
General Specifications | ||
---|---|---|
Wavelength Range | 1100 - 1600 nm | |
AR Coating (All Four Surfaces, Click for Plot) | Ravg < 0.5% at 0° AOI from 1100 - 1600 nm | |
Substrate Material | N-BK7a | |
Dimensional Tolerance | +0.0/-0.2 mm | |
Reflected Beam Deviation | 90° ± 5 arcmin | |
Surface Quality | 40-20 Scratch-Dig |
Item # | Size | Transmitted Wavefront Error (@ 633 nm) |
Transmitted Beam Deviation |
Overall Performanceb |
---|---|---|---|---|
10:90 (R:T) Split Ratio | ||||
BS036a | 5 mm Cube | <λ/4 | 0° ± 5 arcmin | Tabs = 87 ± 10%, Rabs = 7 +10/-7%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
BS039 | 10 mm Cube | Tabs = 87 ± 10%, Rabs = 7 +10/-5%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
||
BS042 | 1/2" (12.7 mm Cube) | |||
BS045 | 20 mm Cube | |||
BS027 | 1" (25.4 mm) Cube | |||
30:70 (R:T) Split Ratio | ||||
BS048a | 5 mm Cube | <λ/4 | <5 arcmin | Tabs = 62 ± 10%, Rabs = 27 ± 10%, Tabs + Rabs > 80%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
BS051 | 10 mm Cube | |||
BS054 | 1/2" (12.7 mm Cube) | |||
BS081 | 20 mm Cube | |||
BS021 | 1" (25.4 mm) Cube | 0° ± 5 arcmin | ||
50:50 (R:T) Split Ratio | ||||
BS009a | 5 mm Cube | <λ/4 | 0° ± 5 arcmin | Tabs = 47 ± 10%, Rabs = 47 ± 10%, Tabs + Rabs > 83%, Tavg + Ravg > 88%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
BS012 | 10 mm Cube | |||
BS006 | 1/2" (12.7 mm) Cube | |||
BS018 | 20 mm Cube | |||
BS015 | 1" (25.4 mm) Cube | |||
BS033 | 2" (50.8 mm) Cube | <λ | Tabs= 47 ± 10% and Rabs= 47 ± 10% (1100 - 1390 nm and 1430 - 1600 nm) Tabs = 45 ± 10% and Rabs = 45 ± 10% (1390 - 1430 nm) Tabs + Rabs > 75%, Tavg + Ravg > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
|
70:30 (R:T) Split Ratio | ||||
BS057a | 5 mm Cube | <λ/4 | <5 arcmin | Tabs = 27 ± 10%, Rabs = 67 +5/-15%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
BS060 | 10 mm Cube | |||
BS063 | 1/2" (12.7 mm Cube) | |||
BS066 | 20 mm Cube | |||
BS024 | 1" (25.4 mm) Cube | |||
90:10 (R:T) Split Ratio | ||||
BS069a | 5 mm Cube | <λ/4 | 0° ± 5 arcmin | Tabs = 7 +10/-5%, Rabs = 87 ± 10%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
BS072 | 10 mm Cube | |||
BS075 | 1/2" (12.7 mm Cube) | |||
BS078 | 20 mm Cube | |||
BS030 | 1" (25.4 mm) Cube |
Thorlabs Lab Fact: Beamsplitter Package Matters
We present laboratory measurements of the polarization angle, split ratio, and total throughput power of a beam transmitted through Thorlabs plate, cube, and pellicle beamsplitters. While all non-polarizing beamsplitters function similarly, the exact performance is different for different types of beamsplitter. Each type of beamsplitter contains its own advantages and disadvantages compared to other types of beamsplitters. Appropriate choice of beamsplitter is essential to sensitive experimental systems. We present a complete analysis and comparison of optical parameters for three common types of non-polarizing beamsplitters.
For our experiment we used the former generation HRS015 stabilized HeNe laser (replaced by the HRS015B) as the light source for our investigation. A linear polarizer is used to set the laser beam's polarization axis to 45° in order to provide equal s- and p-polarized light incident on the beamsplitter. The beamsplitter under investigation was then placed in the beampath, and its split beams directed to appropriate detectors. The total power though the optic, polarization states, split ratios, and angle of incidence effects were investigated under this configuration.
The plots below summarize the measured results for all three types of beamsplitters. From these graphs the performance of each optic can be easily compared to one another. The bottom left plot summarizes the results for the total power throughput for each optic. The total power throughput is measured as the fraction of input power. While the plate and pellicle beamsplitters perform rather similarly, the cube shows signs of absorption inside the optic. Additionally, this plot shows the relative insensitivity of throughput power to angle of incidence. The bottom middle graph summarizes the results for the output polarization angle for each optic. The cube shows the most similar polarization angles between the reflected and transmitted beams, with the plate producing the largest difference in polarization between beams. The bottom right plot summarizes the results for the split ratio, as a fraction of input power, for the beamsplitters. Here it can be shown that the plate beamsplitter demonstrates the most ideal for 50/50 power splitting. For details on the experimental setup employed and the results summarized here, please click here.
Damage Threshold Specificationsa | ||
---|---|---|
Split Ratio | Laser Type | Damage Threshold |
50:50 | Pulsed | 0.25 J/cm2 (1542 nm, 10 ns, 10 Hz, Ø0.282 mm) |
CWb | 50 W/cm (1542 nm, Ø1.030 mm) |
Damage Threshold Data for Thorlabs' 50:50 (R:T) Non-Polarizing Cube Beamsplitters
The specifications to the right are measured data for Thorlabs' non-polarizing cube beamsplitters with wavelength range from 1100 to 1600 nm. Damage threshold specifications are constant for all coatings, regardless of the size of the beamsplitter.
Laser Induced Damage Threshold Tutorial
The following is a general overview of how laser induced damage thresholds are measured and how the values may be utilized in determining the appropriateness of an optic for a given application. When choosing optics, it is important to understand the Laser Induced Damage Threshold (LIDT) of the optics being used. The LIDT for an optic greatly depends on the type of laser you are using. Continuous wave (CW) lasers typically cause damage from thermal effects (absorption either in the coating or in the substrate). Pulsed lasers, on the other hand, often strip electrons from the lattice structure of an optic before causing thermal damage. Note that the guideline presented here assumes room temperature operation and optics in new condition (i.e., within scratch-dig spec, surface free of contamination, etc.). 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. For more information on cleaning optics, please see our Optics Cleaning tutorial.
Testing Method
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. The optic is exposed in 10 locations to this laser beam for 30 seconds (CW) or for a number of pulses (pulse repetition frequency specified). After exposure, the optic is examined by a microscope (~100X magnification) for any visible damage. The number of locations that are damaged at a particular power/energy level is recorded. Next, the power/energy is either increased or decreased and the optic is exposed at 10 new locations. 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 histogram such as that below represents the testing of one BB1-E02 mirror.
![LIDT metallic mirror](https://www.thorlabs.com/images/TabImages/Dielectric_Mirror_Damage_Threshold-300.jpg)
The photograph above is a protected aluminum-coated mirror after LIDT testing. In this particular test, it handled 0.43 J/cm2 (1064 nm, 10 ns pulse, 10 Hz, Ø1.000 mm) before damage.
![LIDT BB1-E02](https://www.thorlabs.com/images/TabImages/Dielectric_Mirror_Exposure_Histogram-390.gif)
Example Test Data | |||
---|---|---|---|
Fluence | # of Tested Locations | Locations with Damage | Locations Without Damage |
1.50 J/cm2 | 10 | 0 | 10 |
1.75 J/cm2 | 10 | 0 | 10 |
2.00 J/cm2 | 10 | 0 | 10 |
2.25 J/cm2 | 10 | 1 | 9 |
3.00 J/cm2 | 10 | 1 | 9 |
5.00 J/cm2 | 10 | 9 | 1 |
According to the test, the damage threshold of the mirror was 2.00 J/cm2 (532 nm, 10 ns pulse, 10 Hz, Ø0.803 mm). 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. While the test results are only representative of one coating run, Thorlabs specifies damage threshold values that account for coating variances.
Continuous Wave and Long-Pulse Lasers
When an optic is damaged by a continuous wave (CW) laser, it is usually due to the melting of the surface as a result of absorbing the laser's energy or damage to the optical coating (antireflection) [1]. Pulsed lasers with pulse lengths longer than 1 µs can be treated as CW lasers for LIDT discussions.
When pulse lengths are between 1 ns and 1 µs, laser-induced damage can occur either because of absorption or a dielectric breakdown (therefore, a user must check both CW and pulsed LIDT). 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. While many optics can handle high power CW lasers, cemented (e.g., achromatic doublets) or highly absorptive (e.g., ND filters) optics tend to have lower CW damage thresholds. These lower thresholds are due to absorption or scattering in the cement or metal coating.
LIDT in linear power density vs. pulse length and spot size. For long pulses to CW, linear power density becomes a constant with spot size. This graph was obtained from [1].
![Intensity Distribution](https://www.thorlabs.com/images/TabImages/Pulsed_Laser_Intensity_Distribution-390.gif)
Pulsed lasers with high pulse repetition frequencies (PRF) may behave similarly to CW beams. 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. For beams with a high PRF both the average and peak powers must be compared to the equivalent CW power. Additionally, for highly transparent materials, there is little to no drop in the LIDT with increasing PRF.
In order to use the specified CW damage threshold of an optic, it is necessary to know the following:
- Wavelength of your laser
- Beam diameter of your beam (1/e2)
- Approximate intensity profile of your beam (e.g., Gaussian)
- Linear power density of your beam (total power divided by 1/e2 beam diameter)
Thorlabs expresses LIDT for CW lasers as a linear power density measured in W/cm. In this regime, the LIDT given as a linear power density can be applied to any beam diameter; one does not need to compute an adjusted LIDT to adjust for changes in spot size, as demonstrated by the graph to the right. Average linear power density can be calculated using the equation below.
The calculation above assumes a uniform beam intensity profile. You must now consider hotspots in the beam or other non-uniform intensity profiles and roughly calculate a maximum power density. For reference, a Gaussian beam typically has a maximum power density that is twice that of the uniform beam (see lower right).
Now compare the maximum power density to that which is specified as the LIDT for the optic. If the optic was tested at a wavelength other than your operating wavelength, the damage threshold must be scaled appropriately. A good rule of thumb is that the damage threshold has a linear relationship with wavelength such that as you move to shorter wavelengths, the damage threshold decreases (i.e., a LIDT of 10 W/cm at 1310 nm scales to 5 W/cm at 655 nm):
While this rule of thumb provides a general trend, it is not a quantitative analysis of LIDT vs wavelength. In CW applications, for instance, damage scales more strongly with absorption in the coating and substrate, which does not necessarily scale well with wavelength. While the above procedure provides a good rule of thumb for LIDT values, please contact Tech Support if your wavelength is different from the specified LIDT wavelength. If your power density is less than the adjusted LIDT of the optic, then the optic should work for your application.
Please note that we have a buffer built in between the specified damage thresholds online and the tests which we have done, which accommodates variation between batches. Upon request, we can provide individual test information and a testing certificate. The damage analysis will be carried out on a similar optic (customer's optic will not be damaged). Testing may result in additional costs or lead times. Contact Tech Support for more information.
Pulsed Lasers
As previously stated, pulsed lasers typically induce a different type of damage to the optic than CW lasers. Pulsed lasers often do not heat the optic enough to damage it; instead, pulsed lasers produce strong electric fields capable of inducing dielectric breakdown in the material. Unfortunately, it can be very difficult to compare the LIDT specification of an optic to your laser. There are multiple regimes in which a pulsed laser can damage an optic and this is based on the laser's pulse length. The highlighted columns in the table below outline the relevant pulse lengths for our specified LIDT values.
Pulses shorter than 10-9 s cannot be compared to our specified LIDT values with much reliability. In this ultra-short-pulse regime various mechanics, such as multiphoton-avalanche ionization, take over as the predominate damage mechanism [2]. In contrast, pulses between 10-7 s and 10-4 s may cause damage to an optic either because of dielectric breakdown or thermal effects. 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.
Pulse Duration | t < 10-9 s | 10-9 < t < 10-7 s | 10-7 < t < 10-4 s | t > 10-4 s |
---|---|---|---|---|
Damage Mechanism | Avalanche Ionization | Dielectric Breakdown | Dielectric Breakdown or Thermal | Thermal |
Relevant Damage Specification | No Comparison (See Above) | Pulsed | Pulsed and CW | CW |
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. For short pulses, energy density becomes a constant with spot size. This graph was obtained from [1].
- Wavelength of your laser
- Energy density of your beam (total energy divided by 1/e2 area)
- Pulse length of your laser
- Pulse repetition frequency (prf) of your laser
- Beam diameter of your laser (1/e2 )
- Approximate intensity profile of your beam (e.g., Gaussian)
The energy density of your beam should be calculated in terms of J/cm2. The graph to the right shows why expressing the LIDT as an energy density provides the best metric for short pulse sources. 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. This calculation assumes a uniform beam intensity profile. 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 energy density that is twice that of the 1/e2 beam.
Now compare the maximum energy density to that which is specified as the LIDT for the optic. If the optic was tested at a wavelength other than your operating wavelength, the damage threshold must be scaled appropriately [3]. 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.
Beam diameter is also important to know when comparing damage thresholds. While the LIDT, when expressed in units of J/cm², scales independently of spot size; large beam sizes are more likely to illuminate a larger number of defects which can lead to greater variances in the LIDT [4]. For data presented here, a <1 mm beam size was used to measure the LIDT. For beams sizes greater than 5 mm, the LIDT (J/cm2) will not scale independently of beam diameter due to the larger size beam exposing more defects.
The pulse length must now be compensated for. The longer the pulse duration, the more energy the optic can handle. For pulse widths between 1 - 100 ns, an approximation is as follows:
Use this formula to calculate the Adjusted LIDT for an optic based on your pulse length. If your maximum energy density is less than this adjusted LIDT maximum energy density, then the optic should be suitable for your application. 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.
Please note that we have a buffer built in between the specified damage thresholds online and the tests which we have done, which accommodates variation between batches. Upon request, we can provide individual test information and a testing certificate. Contact Tech Support for more information.
[1] R. M. Wood, Optics and Laser Tech. 29, 517 (1998).
[2] Roger M. Wood, Laser-Induced Damage of Optical Materials (Institute of Physics Publishing, Philadelphia, PA, 2003).
[3] C. W. Carr et al., Phys. Rev. Lett. 91, 127402 (2003).
[4] N. Bloembergen, Appl. Opt. 12, 661 (1973).
In order to illustrate the process of determining whether a given laser system will damage an optic, a number of example calculations of laser induced damage threshold are given below. For assistance with performing similar calculations, we provide a spreadsheet calculator that can be downloaded by clicking the button to the right. To use the calculator, enter the specified LIDT value of the optic under consideration and the relevant parameters of your laser system in the green boxes. The spreadsheet will then calculate a linear power density for CW and pulsed systems, as well as an energy density value for pulsed systems. These values are used to calculate adjusted, scaled LIDT values for the optics based on accepted scaling laws. This calculator assumes a Gaussian beam profile, so a correction factor must be introduced for other beam shapes (uniform, etc.). The LIDT scaling laws are determined from empirical relationships; their accuracy is not guaranteed. Remember that absorption by optics or coatings can significantly reduce LIDT in some spectral regions. These LIDT values are not valid for ultrashort pulses less than one nanosecond in duration.
![Intensity Distribution](https://www.thorlabs.com/images/TabImages/Pulsed_Laser_Intensity_Distribution-390.gif)
A Gaussian beam profile has about twice the maximum intensity of a uniform beam profile.
CW Laser Example
Suppose that a CW laser system at 1319 nm produces a 0.5 W Gaussian beam that has a 1/e2 diameter of 10 mm. A naive calculation of the average linear power density of this beam would yield a value of 0.5 W/cm, given by the total power divided by the beam diameter:
However, the maximum power density of a Gaussian beam is about twice the maximum power density of a uniform beam, as shown in the graph to the right. Therefore, a more accurate determination of the maximum linear power density of the system is 1 W/cm.
An AC127-030-C achromatic doublet lens has a specified CW LIDT of 350 W/cm, as tested at 1550 nm. CW damage threshold values typically scale directly with the wavelength of the laser source, so this yields an adjusted LIDT value:
The adjusted LIDT value of 350 W/cm x (1319 nm / 1550 nm) = 298 W/cm is significantly higher than the calculated maximum linear power density of the laser system, so it would be safe to use this doublet lens for this application.
Pulsed Nanosecond Laser Example: Scaling for Different Pulse Durations
Suppose that a pulsed Nd:YAG laser system is frequency tripled to produce a 10 Hz output, consisting of 2 ns output pulses at 355 nm, each with 1 J of energy, in a Gaussian beam with a 1.9 cm beam diameter (1/e2). 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. So, the maximum energy density of this beam is ~0.7 J/cm2.
The energy density of the beam can be compared to the LIDT values of 1 J/cm2 and 3.5 J/cm2 for a BB1-E01 broadband dielectric mirror and an NB1-K08 Nd:YAG laser line mirror, respectively. Both of these LIDT values, while measured at 355 nm, were determined with a 10 ns pulsed laser at 10 Hz. Therefore, an adjustment must be applied for the shorter pulse duration of the system under consideration. As described on the previous tab, LIDT values in the nanosecond pulse regime scale with the square root of the laser pulse duration:
This adjustment factor results in LIDT values of 0.45 J/cm2 for the BB1-E01 broadband mirror and 1.6 J/cm2 for the Nd:YAG laser line mirror, which are to be compared with the 0.7 J/cm2 maximum energy density of the beam. While the broadband mirror would likely be damaged by the laser, the more specialized laser line mirror is appropriate for use with this system.
Pulsed Nanosecond Laser Example: Scaling for Different Wavelengths
Suppose that a pulsed laser system emits 10 ns pulses at 2.5 Hz, each with 100 mJ of energy at 1064 nm in a 16 mm diameter beam (1/e2) that must be attenuated with a neutral density filter. For a Gaussian output, these specifications result in a maximum energy density of 0.1 J/cm2. The damage threshold of an NDUV10A Ø25 mm, OD 1.0, reflective neutral density filter is 0.05 J/cm2 for 10 ns pulses at 355 nm, while the damage threshold of the similar NE10A absorptive filter is 10 J/cm2 for 10 ns pulses at 532 nm. As described on the previous tab, the LIDT value of an optic scales with the square root of the wavelength in the nanosecond pulse regime:
This scaling gives adjusted LIDT values of 0.08 J/cm2 for the reflective filter and 14 J/cm2 for the absorptive filter. In this case, the absorptive filter is the best choice in order to avoid optical damage.
Pulsed Microsecond Laser Example
Consider a laser system that produces 1 µs pulses, each containing 150 µJ of energy at a repetition rate of 50 kHz, resulting in a relatively high duty cycle of 5%. This system falls somewhere between the regimes of CW and pulsed laser induced damage, and could potentially damage an optic by mechanisms associated with either regime. As a result, both CW and pulsed LIDT values must be compared to the properties of the laser system to ensure safe operation.
If this relatively long-pulse laser emits a Gaussian 12.7 mm diameter beam (1/e2) at 980 nm, then the resulting output has a linear power density of 5.9 W/cm and an energy density of 1.2 x 10-4 J/cm2 per pulse. 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. As before, the CW LIDT of the optic scales linearly with the laser wavelength, resulting in an adjusted CW value of 6 W/cm at 980 nm. On the other hand, the pulsed LIDT scales with the square root of the laser wavelength and the square root of the pulse duration, resulting in an adjusted value of 55 J/cm2 for a 1 µs pulse at 980 nm. 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. However, the large average linear power density of the laser system may cause thermal damage to the optic, much like a high-power CW beam.
Thorlabs offers a variety of mounting solutions for our beamsplitter cubes. The mounts below allow our cubes to be post-mounted or integrated into our 16 mm or 30 mm cage systems. Post-mountable solutions are compatible with our Ø1/2" Posts as well as Ø1" Posts with 8-32 (M4) taps.
Post-Mountable Mounts for Beamsplitter Cubes | ||||||||
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Click Photo to Enlarge (Cubes Not Included) |
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Item # | PCM(/M) | BSH10(/M) BSH05(/M) BSH20(/M) BSH1(/M) BSH2(/M) |
FBTB(/M) | KM100PM(/M) | KM200PM(/M) | KM100B(/M) | KM200B(/M) | K6XS |
Required Accessories | Base: PCMP(/M) | - | - | Clamp: PM3(/M) or PM4(/M) |
Clamp: PM3(/M) or PM4(/M) |
Clamp: PM3(/M) or PM4(/M) |
Clamp: PM3(/M) or PM4(/M) |
Adapter: K6A1(/M) |
Mounting Options | Ø1/2" Posts | Ø1/2" Postsa,b | Ø1/2" Posts | Ø1/2" Posts | Ø1/2" Posts | Ø1/2" Posts | Ø1/2" Posts | Ø1/2" Posts |
Features | Compact | Compact | Glue-In Mount with Precision Tip, Tilt, and Rotation | Tip and Rotation | Tip and Rotation | Kinematic Mount | Kinematic Mount | 6-Axis Mount |
Compatible Beamsplitter Cube Size(s) |
Up to 20 mm | 10 mm, 1/2", 20 mm, 1", 2" |
5 mm | Up to 20 mmc Up to 1" d |
Up to 20 mmc Up to 1" d Up to 2" e |
Up to 20 mmc Up to 1" d |
Up to 20 mmc Up to 1" d Up to 2" e |
5 mm 10 mm 1/2" |
Cage System Mounts for Beamsplitter Cubes | |||||||||
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Click Photo to Enlarge (Cubes Not Included) |
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Item # | Cage Cube: SC6W |
ARV1 | CRM1(/M) or CRM1P(/M) | Cage Cube: C4W or C6W a | CCM1-4ER(/M) | CCM1-A4ER(/M) | CCM1-B4ER(/M) | CCM1-C4ER(/M) | |
Required Accessories | Clamp: SB6C, Platform: SPM2 |
- | Adapter: K6A1(/M) |
Clamp: B6C, Platform: B3C(/M) or B4C(/M) |
Clamp: B6C, Platform: B3CR(/M) or B4CRP(/M) |
- | - | - | - |
Mounting Options |
16 mm Cage Systems | 30 mm Cage Systems | 30 mm Cage Systems or Ø1/2" Posts | 30 mm Cage Systems | 30 mm Cage Systems or Ø1/2" Posts | ||||
Features | Compact | Compact | Rotation Mount | Fixed or Kinematic Platforms | Rotation Platforms | - | One Rotation Mount | Two Rotation Mounts @ 180° | Two Rotation Mounts @ 90° |
Compatible Beamsplitter Cube Size(s) |
10 mm | 5 mm 10 mm |
5 mm 10 mm 1/2" |
1/2" 20 mm 1" |
5 mm (with BS5CAM Adapter) 10 mm (with BS10CAM Adapter) 1/2" (with BS127CAM Adapter) 20 mm (with BS20CAM Adapter) 1" (Directly Compatible) |
Posted Comments: | |
Kimhan Tan
 (posted 2023-08-10 13:30:33.893) Hi Thorlab team, I am using non-polarized BS018 to split Red light (633nm) and IR (1310nm). As per checked in the BS018 raw data. The transmitivity T and reflectivity R for P-polarization and S-polarization are as follow,
Source P(T) P(R) S(T) S(R)
Red (633nm) 33.7% 21.4% 19.2% 36.5%
IR (1310nm) 47.1% 46.7% 50.8% 42.7%
In my optical system, transmition and reflection are taking place, therefore my Red light and IR light will only remain about 7.0 - 7.2% and 21.7 - 22.0%, respectively, at the detector.
My question is, is there any beamsplitter replacement that can achieve nearly 50% transmission and 50% reflection (split ratio of 50:50) on Red light (633nm) and IR (1310nm)?
Thanks. cdolbashian
 (posted 2023-08-16 11:51:02.0) Thank you for reaching out to us with this inquiry. In this case, I think the best choice for this broad wavelength range would be a polka-dot beamsplitter, as none of our dielectric-coated beamsplitters can produce a 50:50 split for these wavelengths simultaneously. Andreas Baum
 (posted 2022-01-25 03:14:47.01) Good morning,
is there a way to integrate a BS033 2" beamsplitter cube into a 60mm cage system so that it is aligned with the cage system?
Best regards
Andreas Baum jdelia
 (posted 2022-01-31 02:10:55.0) Thank you for contacting Thorlabs. Depending on how you are willing to mount your 2" beamsplitter cube, we may have some solutions for you. I have contacted you directly to discuss your application further. Héctor Álvarez
 (posted 2022-01-19 02:06:41.703) Good morning,
I am using a BS042 10:90 (R:T) to split a linearly polarized laser at 1396 nm. In principle, this non-polarizing cubes have a minimal polarization depende but this is not what I observe in reflexion. The R port changes the output power drastically when the linear polarization is changed with a halfwave plate before the cube. Additionally, in the best case scenario, for this R port I get around 2 % of the incident power (never the 10%). Is this behaviour correct? Any piece of advice? Could you please provide me with an explanation?
Thanks in advance,
Héctor YLohia
 (posted 2022-01-20 03:03:16.0) Thank you for contacting Thorlabs. As stated in the spec sheet, the overall performance over the 1100-1600 nm coating range (0° AOI) is : T_abs = 87 ± 10%, R_abs = 7 +10/-7%, and (T_abs + R_abs) > 85%, |Ts - Tp| < 10% and |Rs - Rp| < 10%", where R_abs= 7 +10/-7%. The behavior you observed is normal for the BS042. The typical reflectance data for the 10:90 BS cubes can be found here:
https://www.thorlabs.com/images/TabImages/NPBS_IR_1090_Reflectance_G2-780.gif. The reflectance data for ~1396 nm is indeed low. user
 (posted 2019-11-28 13:54:11.517) I would like to know what is the biggest ratio you can achieve in a beamsplitter. Can you achieve 99-1 or lower? nbayconich
 (posted 2019-12-11 02:39:43.0) Thank you for contacting Thorlabs, after evaluation a split ratio greater than 99:1 is beyond our current design capabilities. We apologies that we could not provide this at the moment, and we thank you for your feedback.
For your current application, will stacking two BS with a 90:10 ratio be a possible solution for you?
For example, use two CCM1-BS015 and one CM1-CC together. The other possible option is to use beam samplers such as BSF10-C, which will provide approximately 1% reflection with a 45° angle of incidence and a P-Polarized light field. jeremy.hulin2
 (posted 2018-10-17 13:06:41.647) Dear Thorlabs, I want to use the beam splitter BS030 with a 5W CW laser with a diameter of 3mm. Will it handle the beam ? Thanks YLohia
 (posted 2018-10-25 09:43:35.0) Hello, the beamsplitter coating on this can typically only withstand powers in the few mW region. Thus, we don't recommend this beamsplitter for your application. y.s.yong
 (posted 2017-12-04 17:52:55.677) Hi, could you please provide the typical reflection (%) curves for the beam splitters within 900-2100 nm wavelength range (particularly BS030)? Thank you. nbayconich
 (posted 2017-12-08 04:32:31.0) Thank you for contacting Thorlabs. I will reach out to you directly with reflection curves for the BS030 beamsplitter. ekocabas
 (posted 2016-07-10 07:18:14.24) Do you have specs/graphs for the change in output polarization angle for the reflected and transmitted beams as a function of wavelength in the range 1100-1600 nm for the BS015 beam splitter cube? tcohen
 (posted 2012-09-06 10:39:00.0) Response from Tim at Thorlabs: We are able to manufacturer smaller sizes and I have contacted you to discuss your requirements. As for damage thresholds, typically lower wavelengths will reduce the damage threshold of an optic and a longer pulse length with increase it. Our “Damage Threshold” tutorial linked to this page explains more on relating our values for use with different parameters. That being said your energy density is lower than where we would expect to see damage. As always, make sure that the optic is kept clean and the surface quality is maintained to have the best performance. paul.taylor
 (posted 2012-08-31 08:13:51.0) I am considering buying a BS015 cube. I am working with a 1mJ pulse in a 0.45 cm (1e^2) radius beam of 1064 nm light in a Gaussian profile with a 100 ns pulse duration. Given that the fluence is only 1.6mJ/cm^2 - do you think it would be OK from a damage threshold standpoint - given that we are a long way from the specified parameters? jikim
 (posted 2012-08-30 17:58:40.0) Could you manufacture a small size of the "BS024" and the "BS030", e.g. 5 mm or 10 mm? |
Beamsplitter Selection Guide
Thorlabs' portfolio contains many different kinds of beamsplitters, which can split beams by intensity or by polarization. We offer plate and cube beamsplitters, though other form factors exist, including pellicle and birefringent crystal. For an overview of the different types and a comparison of their features and applications, please see our overview. Many of our beamsplitters come in premounted or unmounted variants. Below is a complete listing of our beamsplitter offerings. To explore the available types, wavelength ranges, splitting/extinction ratios, transmission, and available sizes for each beamsplitter category, click More [+] in the appropriate row below.Plate Beamsplitters
Non-Polarizing Plate Beamsplitters |
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Polarizing Plate Beamsplitters |
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Cube Beamsplitters
Non-Polarizing Cube Beamsplitters |
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Polarizing Cube and Polyhedron Beamsplitters |
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Pellicle Beamsplitters
Non-Polarizing Pellicle Beamsplitters |
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Crystal Beamsplitters
Polarizing Crystal Beamsplitters |
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Other
Other Beamsplitters |
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![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
The data above is relative to the power of the incident beam. Note that some light will be absorbed by the beamsplitter coating. The blue shaded regions denote the transmission and reflection bands for which the performance is guaranteed to meet the stated specifications. The data shown here is typical and run-to-run variations will occur within the given specifications. Performance outside the shaded regions is not guaranteed.
Item # | BS036 | BS039 | BS042 | BS045 | BS027 |
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Cube Side Length | 5 mm | 10 mm | 1/2" (12.7 mm) | 20 mm | 1" (25.4 mm) |
Clear Aperture | >3.5 x 3.5 mm | >8.0 x 8.0 mm | >10.2 x 10.2 mm | >16.0 x 16.0 mm | >20.3 x 20.3 mm |
Transmitted Wavefront Errora | <λ/4 | ||||
Transmitted Beam Deviation | 0° ± 5 arcmin | ||||
Overall Performanceb | Tabs = 87 ± 10%, Rabs = 7 +10/-7%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
Tabs = 87 ± 10%, Rabs = 7 +10/-5%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
The data above is relative to the power of the incident beam. Note that some light will be absorbed by the beamsplitter coating. The blue shaded regions denote the transmission and reflection bands for which the performance is guaranteed to meet the stated specifications. The data shown here is typical and run-to-run variations will occur within the given specifications. Performance outside the shaded regions is not guaranteed.
Item # | BS048 | BS051 | BS054 | BS081 | BS021 |
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Cube Side Length | 5 mm | 10 mm | 1/2" (12.7 mm) | 20 mm | 1" (25.4 mm) |
Clear Aperture | >3.5 x 3.5 mm | >8.0 x 8.0 mm | >10.2 x 10.2 mm | >16.0 x 16.0 mm | >20.3 x 20.3 mm |
Transmitted Wavefront Errora | <λ/4 | ||||
Transmitted Beam Deviation | <5 arcmin | 0° ± 5 arcmin | |||
Overall Performanceb | Tabs = 62 ± 10%, Rabs = 27 ± 10%, Tabs + Rabs > 80%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
The data above is relative to the power of the incident beam. Note that some light will be absorbed by the beamsplitter coating. The blue shaded regions denote the transmission and reflection bands for which the performance is guaranteed to meet the stated specifications. The data shown here is typical and run-to-run variations will occur within the given specifications. Performance outside the shaded regions is not guaranteed.
Item # | BS009 | BS012 | BS006 | BS018 | BS015 | BS033 |
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Cube Side Length | 5 mm | 10 mm | 1/2" (12.7 mm) | 20 mm | 1" (25.4 mm) | 2" (50.8 mm) |
Clear Aperture | >3.5 x 3.5 mm | >8.0 x 8.0 mm | >16.0 x 16.0 mm | >20.3 x 20.3 mm | >40.6 x 40.6 mm | |
Transmitted Wavefront Errora |
<λ/4 | <λ | ||||
Transmitted Beam Deviation | 0° ± 5 arcmin | |||||
Overall Performanceb | Tabs = 47 ± 10%, Rabs = 47 ± 10%, Tabs + Rabs > 83%, Tavg + Ravg > 88%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
Tabs= 47 ± 10% and Rabs= 47 ± 10% (1100 - 1390 nm and 1430 - 1600 nm) Tabs = 45 ± 10% and Rabs = 45 ± 10% (1390 - 1430 nm) Tabs + Rabs > 75%, Tavg + Ravg > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
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Damage Threshold |
Pulsed: 0.25 J/cm2 (1542 nm, 10 ns, 10 Hz, Ø0.282 mm) CWc: 50 W/cm (1542 nm, Ø1.030 mm) |
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
The data above is relative to the power of the incident beam. Note that some light will be absorbed by the beamsplitter coating. The blue shaded regions denote the transmission and reflection bands for which the performance is guaranteed to meet the stated specifications. The data shown here is typical and run-to-run variations will occur within the given specifications. Performance outside the shaded regions is not guaranteed.
Item # | BS057 | BS060 | BS063 | BS066 | BS024 |
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Cube Side Length | 5 mm | 10 mm | 1/2" (12.7 mm) | 20 mm | 1" (25.4 mm) |
Clear Aperture | >3.5 x 3.5 mm | >8.0 x 8.0 mm | >10.2 x 10.2 mm | >16.0 x 16.0 mm | >20.3 x 20.3 mm |
Transmitted Wavefront Errora |
<λ/4 | ||||
Transmitted Beam Deviation | <5 arcmin | ||||
Overall Performanceb | Tabs = 27 ± 10%, Rabs = 67 +5/-15%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |
![Back to Top Back to Top](https://www.thorlabs.com/images/arrow_Vert.gif)
The data above is relative to the power of the incident beam. Note that some light will be absorbed by the beamsplitter coating. The blue shaded regions denote the transmission and reflection bands for which the performance is guaranteed to meet the stated specifications. The data shown here is typical and run-to-run variations will occur within the given specifications. Performance outside the shaded regions is not guaranteed.
Item # | BS069 | BS072 | BS075 | BS078 | BS030 |
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Cube Side Length | 5 mm | 10 mm | 1/2" (12.7 mm) | 20 mm | 1" (25.4 mm) |
Clear Aperture | >3.5 x 3.5 mm | >8.0 x 8.0 mm | >10.2 x 10.2 mm | >16.0 x 16.0 mm | >20.3 x 20.3 mm |
Transmitted Wavefront Errora | <λ/4 | ||||
Transmitted Beam Deviation | 0° ± 5 arcmin | ||||
Overall Performanceb | Tabs = 7 +10/-5%, Rabs = 87 ± 10%, Tabs + Rabs > 85%, |Ts - Tp| < 10%, and |Rs - Rp| < 10% |