Protected Gold Mirrors


  • Average Reflectance >96% from 800 nm to 20 µm
  • Round and Square Mirrors Available
  • Packages of 10 Rounds at a Discounted Price

PF20-03-M01

Ø2"

PF05-03-M01

Ø1/2"

PF10-03-M01

Ø1"

PF07-03-M01

Ø19 mm

PFSQ05-03-M01

1/2" x 1/2" 

PFSQ10-03-M01

1" x 1"

PFSQ20-03-M01

2" x 2" 

PF03-03-M01

Ø7 mm

Related Items


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Click to Enlarge

A Number of Metallic Mirror Blanks Mounted in Planets at the Top of One of Our Electron Beam Deposition Coating Chambers

Features

  • Surface Flatness: λ/10 (λ/8 for 2" x 2" Square)
  • Five Round Mirror Diameters: 7 mm, 1/2", 19 mm, 1", and 2"
  • Three Square Mirror Options: 1/2", 1", and 2"
  • Ravg > 96% from 800 nm to 20 μm

Thorlabs offers round and square mirrors with a protected gold coating in various sizes. Protected gold is ideal for use in the IR wavelength range. A protective dielectric overcoat is layered over the gold to help protect it from damage and make cleaning easier. These optics provide >96% average reflectance from 800 nm to 20 μm. Like other mirrors with metallic coatings, these mirrors are relatively insensitive to angle of incidence, as seen in the reflectance curves on the Graphs tab. See the Comparison tab to view the reflectance associated with the various gold mirror options sold by Thorlabs.

Our Ø19 mm mirrors are specifically designed to fit our Polaris Fixed Optic Mounts for laser system design and other OEM applications. This diameter provides a larger clear aperture than Ø1/2" optics while allowing the mounts to maintain a Ø1" footprint. Ø7 mm mirrors are compatible with our MK7(MK7/M) Mini-Series kinematic mirror mount or our LMR7(LMR7/M) fixed optic mount.

The round Ø1/2", Ø1", and Ø2" mirrors are also available in packs of 10 at a discount over the individual price.

For applications which require extremely low thermal expansion, Thorlabs also offers protected gold Zerodur mirrors


Click to Enlarge
Mirrors Ø1/2" and larger are
laser engraved with their part
number for easy identification.

Custom Metallic Mirrors
Thorlabs' metallic mirrors are manufactured at the production facility housed in our headquarters in Newton, NJ. Our optics business unit has a wide breadth of manufacturing capabilities that allow us to offer a variety of custom optics for both OEM sales and low quantity one-off orders. Custom optic sizes, geometries, substrate materials, and coatings are available with prices on modified stock that are comparable to our stock offerings. We can produce individual custom plano, spherical, and aspheric mirrors as well as custom components for optical systems like our galvanometers. To receive more information or inquire about a custom order, please contact Tech Support.

Metal-Coated Plano Mirrors Selection Guide

Wavelength Range

Avg. Reflectance
(Click for Variation)

Coating

Suffix

Coating Comparison

250 nm - 450 nm >90% UV Enhanced Aluminum -F01 icon
Raw Data
450 nm - 20 μm >90% for 450 nm - 2 µm
>95% for 2 - 20 µm
Protected Aluminum -G01
750 nm - 1 µm Rs > 99.0%
RP > 98.5%
Ultrafast-Enhanced Silver -AG icon
Raw Data
450 nm - 20 μm >97.5% for 450 nm - 2 µm
>96% for 2 - 20 µm
Protected Silver -P01
>97% for 450 nm - 2 µm
>95% for 2 - 20 µm
Protected Silvera -P02
800 nm - 20 μm >96% Protected Gold -M01 icon
Raw Data
2 µm - 20 µm >98% MIR Enhanced Gold -M02
800 nm - 20 μm >97% Unprotected Gold -M03
10.6 µm Laser Line >99% Unprotected Gold -L01
Metal-Coated Zerodur® Mirrors
Economy Front Surface Mirrors with Protected Metallic Coatings
  • This variation of our protected silver coating is only found on the PFR14-P02 Rectangular Mirror.
Optical Coatings Guide
Optic Cleaning Tutorial

The shaded regions in the graphs denote the ranges over which we guarantee the specified reflectance. Please note that the reflectance outside of these bands is typical and can vary from lot to lot, especially in out-of-band regions where the reflectance is fluctuating or sloped.

Protected Gold at Near-Normal Incident Angle
Click to Enlarge

Excel Spreadsheet with Raw Data for Protected Gold
Protected Gold at 45 Degree Incident Angle
Click to Enlarge

Excel Spreadsheet with Raw Data for Protected Gold
Damage Threshold Specifications
Coating Designation
(Item # Suffix)
Damage Threshold
-M01 (Pulsed) 2 J/cm2 (1.064 µm, 10 ns, 10 Hz, Ø1.000 mm)
-M01 (CW)a 500 W/cm (1.070 µm, Ø0.089 mm)
750 W/cm (10.6 µm, Ø0.339 mm)
  • The power density of your beam should be calculated in terms of W/cm. For an explanation of why the linear power density provides the best metric for long pulse and CW sources, please see the "Continuous Wave and Long-Pulse Lasers" section below.

Damage Threshold Data for Thorlabs' Protected Gold Mirrors

The specifications to the right are measured data for Thorlabs' protected gold coated mirrors. Damage threshold specifications are constant for all protected gold coated mirrors, regardless of the size or focal length of the mirror.

 

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
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
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.

Linear Power Density Scaling

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

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:

  1. Wavelength of your laser
  2. Beam diameter of your beam (1/e2)
  3. Approximate intensity profile of your beam (e.g., Gaussian)
  4. 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):

CW Wavelength Scaling

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:

Energy Density Scaling

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].

  1. Wavelength of your laser
  2. Energy density of your beam (total energy divided by 1/e2 area)
  3. Pulse length of your laser
  4. Pulse repetition frequency (prf) of your laser
  5. Beam diameter of your laser (1/e2 )
  6. 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):

Pulse Wavelength Scaling

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:

Pulse Length Scaling

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
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:

CW Wavelength Scaling

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:

CW Wavelength Scaling

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:

Pulse Energy Density

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:

Pulse Length Scaling

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:

Pulse Wavelength Scaling

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.


Posted Comments:
Hong Qiu  (posted 2021-07-05 15:56:54.933)
Hello, How thick the gold layer is? I saw two totally different answers, among which one is around 0.1 um and the other one is 1 um. I hope to use it to reflect terahertz waves. Does it work in the THz region? Regards.
YLohia  (posted 2021-07-07 02:58:55.0)
Hello, as an estimate, the gold coating layer is roughly 0.1 um thick. Gold coated mirrors do tend to be good THz reflectors, though we haven't performed extensive testing in this region: https://www.osapublishing.org/ao/abstract.cfm?URI=ao-50-19-3201
Jacques De Beer  (posted 2020-09-26 13:24:11.44)
Good afternoon, Is there an option for a custom size mirror that can be made? I require a mirror with a minimum size of 50 mm x 100 mm. 100 mm x 100 mm is also an option if a rectangle is not a shape that you work with.
YLohia  (posted 2020-09-28 08:35:27.0)
Hello, custom optics can be requested by clicking on the red "Request Quote" button above or by emailing Tech Support (techsupport@thorlabs.com). We will discuss the possibility of offering this customization via email.
user  (posted 2020-03-22 15:11:22.49)
Do you have protected or IR enhanced gold mirror in 25 mm x 36 mm x 1 mm rectangular dimension?
YLohia  (posted 2020-03-23 10:41:09.0)
Hello, thank you for contacting Thorlabs. Unfortunately, we currently do not offer 25 mm x 36 mm x 1 mm gold mirrors. We may, however, be able to offer this as a custom option. We will reach out to you directly to discuss this.
Xiao Guo  (posted 2019-09-04 01:41:33.26)
Dear Sir or Madam, We buy a protected gold mirror from you and wondering the thickness of gold and the thickness of protection layer. Is that available? Thank you very much! Peter
YLohia  (posted 2019-09-04 12:01:27.0)
Hello Peter, thank you for contacting Thorlabs. Unfortunately, we cannot share the layer thicknesses as this information is proprietary.
lebouquj  (posted 2018-06-07 16:52:30.497)
Hello, Do you think it could be possible to get a PF05-03-M01 with coating extending up to the chamfer (say at least 0.2mm) ? Thanks, Jean-Baptiste
nbayconich  (posted 2018-06-12 10:38:38.0)
Thank you for contacting Thorlabs. We can look into providing this as a custom order item. I will reach out to you directly with more information. For any custom requests or special orders please contact techsupport@thorlabs.com directly.
engel  (posted 2018-01-11 15:49:01.62)
Dear Sir or Madam, do you have any measurement for the protected gold mirror concerning reflectivity with a 0° angle of incident and are willing to share? Is around 100nm Sio2 as a protection coating still in use? Thanks in advance, Philip
nbayconich  (posted 2018-01-19 01:52:15.0)
Thank you for contacting Thorlabs. The reflectance data at 12º vs 0º AOI will be similar due to the small angle approximation. Zero degrees AOI cannot be directly measured since there must be space between the source and detector. I will reach out to you directly with additional reflectivity data. The protective layer thickness is still on the order of 100nm however the exact coating thickness is proprietary information.
jean-michel.melkonian  (posted 2017-02-16 11:03:23.01)
Dear Thorlabs, I'm afraid the reflectivity curve of the gold-protected mirror for the P polarization at 45° is totally, awfully wrong. Indeed, at 8.1 µm, I have measured a ~50% reflectivity for the P polarization, while it is close to 100% for the S polarization. The reason for this is a surface plasmon resonance taking place in the gold layer, a plasmon which is excited by the evanescent wave after total internal reflection of the light at the glass/gold interface. According to theoretical calculations, this resonance is located at 8.05 µm in gold, assuming a 148-nm-thick SiO2 protective layer. Obviously, this should not happen with an unprotected mirror gold (except at grazing incidence), nor for the S polarization, nor for a normal incidence. I can send you curves if you like.
tfrisch  (posted 2017-02-17 04:33:38.0)
Hello, thank you for contacting Thorlabs. As the accepted industry standard for reflectance measurement uses broadband incoherent source, that is how our data was collected. As coherent sources in the mid-IR become more common and tunable, effects like the plasmon resonance you note may be more critical to our customers. Thank you for taking the time to discuss this with me. I have shared your concerns to our Laser Division which is committed to identifying, enabling, and accelerating MIR technologies.
chen_zilong  (posted 2016-10-14 13:50:43.517)
I would like to know the phase difference between s and p polarization for the PF10-03-M01 mirrors at 45 degree, and 0 degree angle of incidence at wavelengths of 780nm, 795nm and 810nm. Thank you!
tfrisch  (posted 2016-10-25 09:19:34.0)
Hello, thank you for contacting Thorlabs. The Gold coating M01 has a dielectric coating on top to protect it. While the gold itself should have little effect on the polarization, this dielectric coating will introduce dispersion between the polarization states. Unfortunately, this is not monitored from one coating run to another, and there will be significant variations. You may be interested in our unprotected gold coating M03. I have contacted you with a link including more details.
rodrigo.cortinas  (posted 2016-08-24 05:46:16.38)
Dear Team, I am wondering if there is any "caveat" to the reflectivity of PF20-03-MO1 Gold protected mirror. I am using a 1064nm, 50mW CW laser and the reflectivity hardly gets to 60%. The mirror is nice and clean but it doesnt perform as expected. Thanks in advance.
david.szwer  (posted 2015-11-23 14:02:59.16)
Dear Thorlabs, We use gold mirrors (I think they are protected ones) at 792nm and 1584nm. Do you happen to know whether there are any significant polarisation-dependent phase shifts (e.g. leading to polarisation ellipticity) around these wavelengths, please? Thank you, David.
besembeson  (posted 2015-11-25 01:50:22.0)
Response from Bweh at Thorlabs USA: Yes there are polarization dependent phase shifts at these wavelengths for these metallic coated mirrors. Unless the input is purely S- or P-, the output polarization will be modified. Our UK division will share with you theoretical data on the phase shift for S- and P- at wavelengths including 792nm and 1548nm.
user  (posted 2015-03-06 11:37:47.247)
Dear Sir or Madame, could you tell me with which resolution your the reflectance data have been obtained?
myanakas  (posted 2015-03-30 08:54:57.0)
Response from Mike at Thorlabs: Thank you for your feedback. Our reflectance data on the "Graphs" tab is measured about every 10 nm from 300 nm to 20 um. The raw data can be found under the plots by clicking on the "Excel Spreadsheet" link under each plot.
valery.blb  (posted 2015-03-04 07:16:23.89)
Dear Sirs, Could you kindly provide the results for reflactanse (%) for your protected gold coating (for mirror PF10-03-M01) for AOI= 81 degrees, 3-16 mkm, S- and P- polarization, if possible? King regards, Valery
jlow  (posted 2015-03-05 02:56:13.0)
Response from Jeremy at Thorlabs: I will contact you directly about measuring this.
b.schrode  (posted 2014-10-09 10:28:57.017)
Is this information (Poster: jjurado Posted Date: 2011-03-23 16:59:00.0) still valid? "The thickness of the gold coating on our PF series mirrors ranges from 0.10 um to 0.13 um."
besembeson  (posted 2014-10-10 10:05:56.0)
Response from Bweh at Thorlabs: The gold coating thickness is around 1um and the overcoat is around 0.1um.
cory.stinson  (posted 2014-03-24 16:01:35.24)
Would it be possible to get a Zemax encrypted coating file (ZEC file) for the protected gold mirror coating?
besembeson  (posted 2014-03-27 04:26:27.0)
Response from Bweh E at Thorlabs: Thanks for contacting Thorlabs. I will send you separate email with the requested file.
adr5109  (posted 2014-01-17 18:32:05.167)
Is there any information on the GVD of your gold mirrors? It's listed for the silver ones, but I couldn't find anything about the gold. Thanks, Adam
jlow  (posted 2014-02-03 02:09:36.0)
Response from Jeremy at Thorlabs: We do not have the GVD value for the protected gold mirror. We can arrange for one to be sent to you for GVD measurement.
oliver.hohn  (posted 2013-09-16 11:09:20.52)
Hi, I have a question regarding the reflectance of the protected gold coated mirrors. There appears to be several discrepancies between the reflectances in the graphs and those in the excel sheets, also the one in the catalogue seems to differ. Could you give me some information as to what data is correct? Best regards, Oliver
sharrell  (posted 2013-09-16 09:58:00.0)
Response from Sean at Thorlabs: Thank you for pointing out this error. The Excel file on our website was incorrect and has been updated. While we make every attempt to keep the catalog pdf files on our website up-to-date, our V21 catalog is now two years old and unfortunately does not have the latest data. We are investigating the best way to rectify this situation, however if shopping using the catalog please be aware that specifications may have been updated and our website contains the most current information.
jlow  (posted 2012-12-24 10:32:00.0)
Response from Jeremy at Thorlabs: The exact coating thicknesses are not something that we can provide because it is considered proprietary information. I will get in touch with you directly to initiate a discussion on this.
dave.kielpinski  (posted 2012-12-20 01:38:11.667)
I would also like to know the thickness and material of the protective coating, on both the protected gold and the protected aluminum mirrors. In the previous comments, Thorlabs reps seem to say that the thickness is anywhere between 100 and 250 nm. Unfortunately I need to know the thickness more accurately (to 10 nm if possible). Could someone help me please? Thanks, Dave
tholste  (posted 2012-08-01 09:58:00.0)
A response from Tor at Thorlabs: Sorry for the mistake, the coating is actually SiO2.
jlow  (posted 2012-07-31 18:57:00.0)
A response from Jeremy at Thorlabs: The protective layer is made from SiO and the thickness is on the order of 100nm.
swen.kunzel  (posted 2012-07-28 20:23:33.0)
Can you tell me of what material the protective layer is made of? And what is the thickness of it?
bdada  (posted 2012-05-17 16:04:00.0)
Response from Buki at Thorlabs: Thank you for your feedback. We are in the process of getting CW test data. Once we have it we will include it in the specifications on our website. As a guideline, please use 500W/cm^2 for a 1mm diameter beam at 1064nm. Please contact TechSupport@thorlabs.com if you have further questions.
user  (posted 2012-05-16 17:08:42.0)
Do you have any CW laser damage number, generally it would be nice to have this data in your specs box. My immediate need is to know the CW damage threshold intensity at 10.6 um.
bdada  (posted 2012-02-13 15:15:00.0)
Response from Buki at Thorlabs to: Thank you for your feedback. Our protected gold-coated mirrors are specified for 800 nm to 20 µm, so we provide reflectance data down to 600nm in the "graphs" tab on this page. If you would like an extended reflectance curve down further into the visible, please contact us at TechSupport@thorlabs.com
user  (posted 2012-02-12 14:38:45.0)
A plot of the reflectivity in the visible would really help as we often use visible and IR lasers in a single setup.
jjurado  (posted 2011-03-23 16:59:00.0)
Response from Javier at Thorlabs to acurtis: Thank you for contacting us. The thickness of the gold coating on our PF series mirrors ranges from 0.10 um to 0.13 um. The thickness of the protective layer is 0.148 um. Regards.
acurtis  (posted 2011-03-23 14:18:22.0)
I would just like to know the approximate thickness of the protective coating put on your gold mirrors (within 10nm if possible). We just need this information for some spectral analysis we are doing. Thanks.
jjurado  (posted 2011-02-01 15:59:00.0)
Response from Javier at Thorlabs to max.schiller: Thank you very much for submitting your inquiry. The reflectivity of our protected gold, silver, and aluminum mirrors is in the range of 98% at 45 degree angle of incidence. I will send you complete reflectivity plots shortly, and we will also post this information on the web within the next few days.
max.schiller  (posted 2011-02-01 13:58:09.0)
Hi. Could you please provide me with reflectivity for the Protected Gold, Protected Silver and Protected Aluminium coatings at 4.62 um and 45° incident angle? Regards, Max
tor  (posted 2010-11-24 16:38:56.0)
A response from Tor at Thorlabs to tuffmcguff: The thickness of the protective coating is 250nm and a refractive index of 1.7 can be expected in the visible band.
tuffmcguff  (posted 2010-11-23 18:56:24.0)
What is the thickness of the protective coating (not the actual gold coating) on the model PF20-03-M01 mirror? Also, what is the index of refraction of the protective coating material?
tor  (posted 2010-11-10 17:13:50.0)
A response from Tor at Thorlabs to nick: Thank you for pointing out this discrepancy. The correct parallelism is =3 arcmin, and we have updated the webs spec to show this.
nick  (posted 2010-11-10 12:52:38.0)
Can you please confirm if the parrallelism of the mirror is < 3 arcmin (per the drawing PDF), or < 5 arcmin (per the website)?
badgie  (posted 2010-05-14 12:23:15.0)
Dear Thorlabs, You have once again demonstrated that you are an awesome company. Several times in the last year you have made minor tweaks to trivial products which have showed a real responsivity (so to speak) to the community, falling into the "why didnt I think of that" and "this is going to make my life easier" First, it was switching power connectors so that one could no longer plug your 150V power supplies into photodiodes (ok, that was a while ago) but recently it was slots in you thread adapters (no longer with they be stuck!) and now it is allowing raw data downloads. Thanks! Oh, and by the way, sending t-shirts is great... I recently, and completely without out thinking, wore an older thorlabs tee to a Newport sponsored pizza event at Stanford. -Tony Stanford University
apalmentieri  (posted 2010-01-25 20:10:30.0)
A response from Adam at Thorlabs to andreas: The gold coating should reflect quote well in the THz regime. Based on the current theoretical information that we have the %R should be greater than 90%. I will email the current information we can provide.
andreas.bartelt  (posted 2010-01-25 17:09:02.0)
Hi! Can you tell me the reflectivity of your Protected Gold Mirrors in the THz regime (around 300 µm wavelength)? Thanks you! Best regards, Andreas Bartelt
apalmentieri  (posted 2009-12-18 10:34:08.0)
A response from Adam at Thorlabs: We do have some data that shows the performance out to 10.6um. I will send this data to your email.
thomasce2  (posted 2009-12-18 09:16:10.0)
Hi, Would like to use these mirrors (protected gold) at 9.1 microns (Isotope CO2) and 10.6 microns (CO2). The performance graphs only go to 2.5 microns. It would be a big help to know the actual reflectivity at 9.1 microns and 10.6 microns. regards, tommy thomas
david.ogden  (posted 2008-07-08 11:34:37.0)
can you tell me the damage threshold of the protected gold mirrors - - OK with 2 W of 150 fs pulsed IR?
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Round Protected Gold Mirrors

Item # PF03-03-M01 PF05-03-M01 PF07-03-M01 PF10-03-M01 PF20-03-M01
Diameter 7.0 mm 1/2" (12.7 mm) 19.0 mm 1" (25.4 mm) 2" (50.8 mm)
Diameter Tolerance +0.0 mm / -0.1 mm
Thickness 2.0 mm (0.08") 6.0 mm (0.24") 6.0 mm (0.24") 6.0 mm (0.24") 12.0 mm (0.47")
Thickness Tolerance ±0.2 mm
Reflectance (Average) >96% for 800 nm - 20 μm
Reflectance Curve (Click for Plot)

12° AOI

45° AOI
Substrate Fused Silica
Front Surface Flatness
(Peak to Valley)
λ/10 @ 633 nm
Surface Quality 40-20 Scratch-Dig
Parallelism ≤3 arcmin
Clear Aperture >90% of Diameter
Damage Threshold (Pulsed) 2 J/cm2 at 1.064 µm, 10 ns, 10 Hz, Ø1.000 mm
Damage Threshold (CW)a 500 W/cm at 1.070 µm, Ø0.089 mm
750 W/cm at 10.6 µm, Ø0.339 mm
  • The power density of your beam should be calculated in terms of W/cm. For an explanation of why the linear power density provides the best metric for long pulse and CW sources, please see the Damage Thresholds tab.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
PF03-03-M01 Support Documentation
PF03-03-M01Ø7.0 mm Protected Gold Mirror
$31.77
7-10 Days
PF05-03-M01 Support Documentation
PF05-03-M01Ø1/2" Protected Gold Mirror
$37.14
Today
PF05-03-M01-10 Support Documentation
PF05-03-M01-10 Ø1/2" Protected Gold Mirror, 10 Pack
$324.42
Today
PF07-03-M01 Support Documentation
PF07-03-M01Ø19.0 mm Protected Gold Mirror
$51.09
Today
PF10-03-M01 Support Documentation
PF10-03-M01Ø1" Protected Gold Mirror
$56.26
Today
PF10-03-M01-10 Support Documentation
PF10-03-M01-10Ø1" Protected Gold Mirror, 10 Pack
$486.08
Today
PF20-03-M01 Support Documentation
PF20-03-M01Ø2" Protected Gold Mirror
$115.83
Today
PF20-03-M01-10 Support Documentation
PF20-03-M01-10Ø2" Protected Gold Mirror, 10 pack
$1,112.82
Today
Back to Top

Square Protected Gold Mirrors

Item # PFSQ05-03-M01 PFSQ10-03-M01 PFSQ20-03-M01
Face Dimensions 1/2" x 1/2" (12.7 mm x 12.7 mm) 1" x 1" (25.4 mm x 25.4 mm) 2" x 2" (50.8 mm x 50.8 mm)
Face Dimension Tolerance +0.0 mm / -0.1 mm
Thickness 6.0 mm (0.24")
Thickness Tolerance ±0.2 mm
Reflectance (Average) >96% for 800 nm - 20 μm
Reflectance Curve (Click for Plot)

12° AOI

45° AOI
Substrate UV Fused Silica
Front Surface Flatness
(Peak to Valley)
λ/10 @ 633 nm λ/8 @ 633 nm
Surface Quality 40-20 Scratch-Dig
Parallelism ≤3 arcmin
Clear Aperture >90% of Dimension
Damage Threshold (Pulsed) 2 J/cm2 at 1.064 µm, 10 ns, 10 Hz, Ø1.000 mm
Damage Threshold (CW)a 500 W/cm at 1.070 µm, Ø0.089 mm
750 W/cm at 10.6 µm, Ø0.339 mm
  • The power density of your beam should be calculated in terms of W/cm. For an explanation of why the linear power density provides the best metric for long pulse and CW sources, please see the Damage Thresholds tab.
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
PFSQ05-03-M01 Support Documentation
PFSQ05-03-M011/2" x 1/2" Protected Gold Mirror
$37.14
Today
PFSQ10-03-M01 Support Documentation
PFSQ10-03-M011" x 1" Protected Gold Mirror
$65.51
Today
PFSQ20-03-M01 Support Documentation
PFSQ20-03-M012" x 2" Protected Gold Mirror
$135.42
7-10 Days