N-BK7 Bi-Convex Lenses (AR Coating: 1050 - 1700 nm)


  • Positive Focal Length for Use at Finite Conjugates
  • Broadband AR Coating Wavelength Range: 1050 - 1700 nm
  • Zemax Files Available

LB1157-C

(Ø6 mm)

LB1258-C

(Ø1/2")

LB1494-C

(Ø9 mm)

LB1027-C

(Ø1")

LB1106-C

(Ø2")

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N-BK7 Bi-Convex Spherical Singlets
Lens Shape Convex/Convex
Material N-BK7 (Grade A)
AR Coating
Wavelength Rangea
1050 - 1700 nm
AR Coating Reflectance Ravg < 0.5%
Design Wavelength 587.6 nm 
Index of Refraction 1.517 (@ 587.6 nm)
Surface Quality 40-20 Scratch-Dig
Spherical Surface Powerb 3λ/2
Surface Irregularityb λ/4
Damage Thresholdc 7.5 J/cm2 (1542 nm, 10 ns, 10 Hz, Ø0.123 mm)
Abbe Number Vd = 64.17
Centration ≤3 arcmin
Clear Aperture >90% of Diameter
Diameter Tolerance +0.0 mm / -0.1 mm
Focal Length Tolerance ±1%
  • Also available uncoated, with an -A coating for the 350 - 700 nm range, an -AB coating for the 400 - 1100 nm range, or a -B coating for the 650 - 1050 nm range.
  • Where λ = 633 nm
  • Limited by the antireflection coating.
Zemax Files
Click on the red Document icon next to the item numbers below to access the Zemax file download. Our entire Zemax Catalog is also available.

Features

  • Material: N-BK7
  • AR Coated for the 1050 - 1700 nm Range
  • Available Sizes: Ø6.0 mm, Ø9.0 mm, Ø1/2", Ø1", and Ø2"
  • Focal Lengths Available from 10.0 mm to 1.0 m
  • Well Suited for Many Finite Imaging Applications

Thorlabs' C-Coated N-BK7 Bi-Convex Lenses are fabricated from N-BK7 and feature an antireflection coating for the 1050 - 1700 nm range on both surfaces. N-BK7 is probably the most common optical glass used for high quality optical components. It is typically chosen whenever the additional benefits of UV fused silica (i.e., good transmission further into the UV and a lower coefficient of thermal expansion) are not necessary.

Bi-convex lenses are popular for many finite imaging applications. This type of lens is best suited for use in situations where the object and image are on opposite sides of the lens and the ratio of the image and object distances (conjugate ratio) is between 0.2 and 5. These lenses are designed to have a focal length of f= (R1*R2)/((n-1)*(R2-R1)).

Although this page features our C-coated (1050 - 1700 nm) bi-convex lenses, these lenses are also available uncoated or with a -A (350 - 700 nm), -AB (400 - 1100 nm), or -B (650 - 1050 nm) antireflection coating deposited on each surface to reduce the amount of reflected light. Links to each of these pages can be found in the table to the right. Please see the Graphs tab for coating details.

Lens kits are available. Please click here for information.

Optic Cleaning Tutorial
Optical Coatings and Substrates
Lens Tutorial
Quick Links to Other Spherical Singlets
Plano-Convex Bi-Convex Best Form Plano-Concave Bi-Concave Positive Meniscus Negative Meniscus

Below is the transmission curve for N-BK7, a RoHS-compliant form of BK7. Total Transmission is shown for a 10 mm thick, uncoated sample and includes surface reflections. Each N-BK7 bi-convex lenses can be ordered uncoated or with one of the following broadband AR coatings: 350 - 700 nm (designated with -A), 400 - 1100 nm (designated as -AB), 650 - 1050 nm (designated as -B), or 1050 - 1700 nm (designated as -C, available below). 

Our high-performance multilayer AR coatings have an average reflectance of less than 0.5% (per surface) across the specified wavelength ranges and provide good performance for angles of incidence (AOI) between 0° and 30° (0.5 NA). For optics intended to be used at large incident angles, consider using a custom coating optimized at a 45° angle of incidence; this custom coating is effective from 25° to 52°. The plot shown below indicates the performance of the standard coatings in this family as a function of wavelength. Broadband coatings have a typical absorption of 0.25%, which is not shown in the reflectivity plots.

N-BK7 Transmittance
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Click Here for Raw Data
N-BK7 C-Coating Transmittance
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Click Here for Raw Data
The blue-shaded region indicates the specified 1050 - 1700 nm wavelength range where specifications are guaranteed.

Thorlabs' Standard Broadband Antireflection Coatings

Key Quality Control Equipment
  • TriOptics OptiSpheric
  • Zygo GPI-XP/D Interferometer
  • PerkinElmer Lambda 1050 Spectrophotometer
  • Agilent Cary 5000 Spectrophotometer
Click to Enlarge
A Thorlabs technician measuring the irregularity of one of our singlets using a Zygo GPI-XP/D Interferometer.

Introduction
Thorlabs has a series of quality control procedures in order to ensure our singlets meet our standards and specifications. This starts with in-process inspections of the lens’ imaging capabilities and ends with a final inspection of surface quality and dimensions. Specifications for particular products can be found in their linked documentation by clicking the  symbol. This tab will take you through the general process used to check for quality.

Singlet Quality Practices
In-process inspection begins once the singlet has been shaped to specifications. Focal length, surface irregularity, and surface power are checked, following sampling plan Level VI given in MIL-PRF-13830B (see below). These three specifications are imperative for proper imaging. Surface irregularity of parts is kept to below either a quarter wavelength or a half wavelength at 633 nm, depending on the material of the singlet. Below is a graph of over 200 batches of singlets with irregularity data of both their front and back sides.

At this point, some uncoated singlets will proceed to final inspection, while others will receive an antireflective (AR) coating. The application of optical coatings has its own in-process inspections. To ensure the AR coating is applied properly, we verify both reflectance and transmission performance by scanning witness pieces using spectrophotometry; the material of these 2 mm thick witness samples matches the other parts in the run. For reflectance verification, we use at least one witness sample for each coating run. Transmitting optics receive two AR coatings, one on each surface, so for the verification of transmission, we use one witness sample that is also coated on both of its sides. Large runs use multiple witness samples to ensure the uniformity across the deposition chamber. By testing coating performance during every run, variance over time is kept low. To see how coatings vary, see the table below.

Final inspection of both uncoated and AR-coated singlets includes a batch check of diameter and thickness and a 100% visual check to ensure that the surface quality, chamfer, and clear aperture meet our published specifications. While surface quality is cosmetic to a degree, scratches, digs, and other inclusions in the surface of a part can increase the chances of damage to the singlet when used with high-power sources. These inspections are done in a clean, dark room under lighting that meets the requirements of MIL-PRF-13830B. Inspection under a single light source in a dark room allows for inconsistencies in the glass to be located without being obscured by glare or reflections.

MIL-PRF-13830B: Performance Specifications for Optical Components
MIL-PRF-13830B is a document created by the U.S. Army Armament Research, Development and Engineering Center's Defense Quality and Standardization Office for the specifications covering how finished optical components should be manufactured, assembled, and inspected. While primarily for use in letting the military dictate how products they use can be incorporated into their equipment, these standards have been adopted by many optics manufacturers. To download a copy of the full document, click here.

-A Coating
350 nm to 700 nm
-B Coating
650 nm to 1050 nm
-C Coating
1050 nm to 1700 nm
Singlet
Irregularity
Coating Variance:
Transmission

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Coating Variance:
Reflectance

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Disclaimer: The coated transmission data presented here are of 2 mm thick witness samples of N-BK7 or equivalent glass, and all the data here are typical. Some variations in performance data will occur from lot to lot. Please contact Technical Support with any questions regarding the use or reliability of these data.

BK7 Index of Refraction
Click on the image to download the raw data. In the thick lens equation, use the index of refraction for N-BK7 at the wavelength of interest to approximate the wavelength-dependent focal length of any of the plano-convex lenses.

The focal length of a thick spherical lens can be calculated using the thick lens equation below. In this expression, nl  is the index of refraction of the lens, R1 and R2 are the radii of curvature for surfaces 1 and 2, respectively, and d is the center thickness of the lens.

thick lens equation

For bi-convex lenses, where the front and back radii of curvature are equal in magnitude and opposite in sign, R1 = -R2 = R, we have

Lens Equation Final Biconvex

The focal length of the lens calculated using the simplified thick lens equation directly above is the distance between the second (back) principle plane (H") and the position at which a collimated beam incident on the curved surface of the bi-convex is focused. The same analysis can be performed using a point source and the first (front) principle plane (H'). The principle plane positions of a thick lens can be calculated with the following equations:

principal plane equation one and Principal plane equation two

Again, for the same bi-convex lens, R1 = -R2 = R, we can solve for H' and H' :

Principle Plane Final

Damage Threshold Specifications
Coating Designation
(Item # Suffix)
Damage Threshold
-C 7.5 J/cm2 (1542 nm, 10 ns, 10 Hz, Ø0.123 mm)

Damage Threshold Data for Thorlabs' C-Coated N-BK7 Singlet Lenses

The specifications to the right are measured data for Thorlabs' C-coated N-BK7 spherical singlet lenses. Damage threshold specifications are constant for all C-coated N-BK7 lenses, regardless of the size or focal length of the lens.

 

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.

CXY1A in 30 mm Cage System
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CXY1A Translation Mount and
SM1 Lens Tube Mounted in a
30 mm Cage System
Threaded Mounting Adapter
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Ø1" Optic Mounted in a
ST1XY-S XY Translator

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LMR1 Fixed Mount with Ø1" Lens

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LM2XY Translating Mount with Ø2" Lens
Recommended Mounting Options for Thorlabs Lenses
Item # Mounts for Ø2 mm to Ø10 mm Optics
Imperial Metric
(Various) Fixed Lens Mounts and Mini-Series Fixed Lens Mounts for Small Optics, Ø5 mm to Ø10 mm
(Various) Small Optic Adapters for Use with Standard Fixed Lens Mounts, Ø2 mm to Ø10 mm
Item # Mounts for Ø1/2" (Ø12.7 mm) Optics
Imperial Metric
LMR05 LMR05/M Fixed Lens Mount for Ø1/2" Optics
MLH05 MLH05/M Mini-Series Fixed Lens Mount for Ø1/2" Optics
LM05XY LM05XY/M Translating Lens Mount for Ø1/2" Optics
SCP05 16 mm Cage System, XY Translation Mount for Ø1/2" Optics
(Various) Ø1/2" Lens Tubes,
Optional SM05RRC Retaining Ring for High-Curvature Lenses (See Below)
Item # Mounts for Ø1" (Ø25.4 mm) Optics
Imperial Metric
LMR1 LMR1/M Fixed Lens Mount for Ø1" Optics
LM1XY LM1XY/M Translating Lens Mount for Ø1" Optics
ST1XY-S ST1XY-S/M Translating Lens Mount with Micrometer Drives (Other Drives Available)
CXY1A 30 mm Cage System, XY Translation Mount for Ø1" Optics
(Various) Ø1" Lens Tubes,
Optional SM1RRC Retaining Ring for High-Curvature Lenses (See Below)
Item # Mount for Ø1.5" Optics
Imperial Metric
LMR1.5 LMR1.5/M Fixed Lens Mount for Ø1.5" Optics
(Various) Ø1.5" Lens Tubes,
Optional SM1.5RR Retaining Ring for Ø1.5" Lens Tubes and Mounts
Item # Mounts for Ø2" (Ø50.8 mm) Optics
Imperial Metric
LMR2 LMR2/M Fixed Lens Mount for Ø2" Optics
LM2XY LM2XY/M Translating Lens Mount for Ø2" Optics
CXY2 60 mm Cage System, XY Translation Mount for Ø2" Optics
(Various) Ø2" Lens Tubes,
Optional SM2RRC Retaining Ring for High-Curvature Lenses (See Below)
Item # Adjustable Optic Mounts
Imperial Metric
LH1 LH1/M Adjustable Mount for Ø0.28" (Ø7.1 mm) to Ø1.80" (Ø45.7 mm) Optics
LH2 LH2/M Adjustable Mount for Ø0.77" (Ø19.6 mm) to Ø2.28" (Ø57.9 mm) Optics
VG100 VG100/M Adjustable Clamp for Ø0.5" (Ø13 mm) to Ø3.5" (Ø89 mm) Optics
SCL03 SCL03/M Self-Centering Mount for Ø0.15" (Ø3.8 mm) to Ø1.77" (Ø45.0 mm) Optics
SCL04 SCL04/M Self-Centering Mount for Ø0.15" (Ø3.8 mm) to Ø3.00" (Ø76.2 mm) Optics
LH160C LH160C/M Adjustable Mount for 60 mm Cage Systems,
Ø0.50" (Ø13 mm) to Ø2.00" (Ø50.8 mm) Optics
SCL60CA SCL60C/M Self-Centering Mount for 60 mm Cage Systems,
Ø0.15" (Ø3.8 mm) to Ø1.77" (Ø45.0 mm) Optics

Mounting High-Curvature Optics

Thorlabs' retaining rings are used to secure unmounted optics within lens tubes or optic mounts. These rings are secured in position using a compatible spanner wrench. For flat or low-curvature optics, standard retaining rings manufactured from anodized aluminum are available from Ø5 mm to Ø4". For high-curvature optics, extra-thick retaining rings are available in Ø1/2", Ø1", and Ø2" sizes.

Extra-thick retaining rings offer several features that aid in mounting high-curvature optics such as aspheric lenses, short-focal-length plano-convex lenses, and condenser lenses. As shown in the animation to the right, the guide flange of the spanner wrench will collide with the surface of high-curvature lenses when using a standard retaining ring, potentially scratching the optic. This contact also creates a gap between the spanner wrench and retaining ring, preventing the ring from tightening correctly. Extra-thick retaining rings provide the necessary clearance for the spanner wrench to secure the lens without coming into contact with the optic surface.


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Ø1/2" (12.7 mm) N-BK7 Bi-Convex Lenses (AR Coating: 1050 - 1700 nm)

Item # Diameter Focal Lengtha Diopterb Radius of Curvature Center Thickness Edge Thickness Back Focal Lengtha Reference
Drawing
LB1092-C 12.7 mm 15.0 mm +66.6 14.6 mm 4.7 mm 1.8 mm 13.4 mm Bi-Convex Lens Drawing
LB1450-C 12.7 mm 20.0 mm +50.0 19.9 mm 3.9 mm 1.8 mm 18.7 mm
LB1014-C 12.7 mm 25.0 mm +40.0 25.2 mm 3.4 mm 1.8 mm 23.8 mm
LB1258-C 12.7 mm 30.0 mm +33.3 30.4 mm 3.1 mm 1.8 mm 28.9 mm
LB1378-C 12.7 mm 40.0 mm +25.0 40.7 mm 2.8 mm 1.8 mm 39.1 mm
LB1844-C 12.7 mm 50.0 mm +20.0 51.1 mm 2.6 mm 1.8 mm 49.1 mm
LB1187-C 12.7 mm 100.0 mm +10.0 102.6 mm 2.2 mm 1.8 mm 99.3 mm

Suggested Fixed Lens Mount: LMR05(/M)

  • Focal lengths are listed at the design wavelength, 587.6 nm.
  • Reciprocal of the Focal Length in Meters
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LB1092-C Support Documentation
LB1092-CN-BK7 Bi-Convex Lens, Ø1/2", f = 15.0 mm, ARC: 1050 - 1700 nm
$42.76
Today
LB1450-C Support Documentation
LB1450-CN-BK7 Bi-Convex Lens, Ø1/2", f = 20.0 mm, ARC: 1050 - 1700 nm
$42.18
Today
LB1014-C Support Documentation
LB1014-CN-BK7 Bi-Convex Lens, Ø1/2", f = 25.0 mm, ARC: 1050 - 1700 nm
$40.39
Today
LB1258-C Support Documentation
LB1258-CN-BK7 Bi-Convex Lens, Ø1/2", f = 30.0 mm, ARC: 1050 - 1700 nm
$40.09
Today
LB1378-C Support Documentation
LB1378-CN-BK7 Bi-Convex Lens, Ø1/2", f = 40.0 mm, ARC: 1050 - 1700 nm
$39.81
Lead Time
LB1844-C Support Documentation
LB1844-CN-BK7 Bi-Convex Lens, Ø1/2", f = 50.0 mm, ARC: 1050 - 1700 nm
$39.50
Today
LB1187-C Support Documentation
LB1187-CN-BK7 Bi-Convex Lens, Ø1/2", f = 100.0 mm, ARC: 1050 - 1700 nm
$39.50
Today
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Ø1" (25.4 mm) N-BK7 Bi-Convex Lenses (AR Coating: 1050 - 1700 nm)

Item # Diameter Focal Lengtha Diopterb Radius of Curvature Center Thickness Edge Thickness Back Focal Lengtha Reference
Drawing
LB1761-C 25.4 mm 25.4 mm +39.4 24.5 mm 9.0 mm 1.9 mm 22.2 mm Bi-Convex Lens Drawing
LB1757-C 25.4 mm 30.0 mm +33.2 29.5 mm 7.7 mm 2.0 mm 27.3 mm
LB1811-C 25.4 mm 35.0 mm +28.6 34.9 mm 6.8 mm 2.0 mm 32.7 mm
LB1027-C 25.4 mm 40.0 mm +25.0 40.1 mm 6.1 mm 2.0 mm 37.9 mm
LB1471-C 25.4 mm 50.0 mm +20.0 50.6 mm 5.2 mm 2.0 mm 48.2 mm
LB1596-C 25.4 mm 60.0 mm +16.7 61.0 mm 4.7 mm 2.0 mm 58.4 mm
LB1901-C 25.4 mm 75.0 mm +13.3 76.6 mm 4.1 mm 2.0 mm 73.6 mm
LB1676-C 25.4 mm 100.0 mm +10.0 102.4 mm 3.6 mm 2.0 mm 98.8 mm
LB1904-C 25.4 mm 125.0 mm +8.0 128.2 mm 3.3 mm 2.0 mm 123.9 mm
LB1437-C 25.4 mm 150.0 mm +6.7 154.0 mm 3.1 mm 2.0 mm 149.0 mm
LB1294-C 25.4 mm 175.0 mm +5.7 179.8 mm 2.9 mm 2.0 mm 174.0 mm
LB1945-C 25.4 mm 200.0 mm +5.0 205.6 mm 2.8 mm 2.0 mm 199.1 mm
LB1056-C 25.4 mm 250.0 mm +4.0 257.1 mm 2.6 mm 2.0 mm 249.1 mm
LB1779-C 25.4 mm 300.0 mm +3.3 308.6 mm 2.5 mm 2.0 mm 299.2 mm
LB1391-C 25.4 mm 400.0 mm +2.5 411.7 mm 2.4 mm 2.0 mm 399.2 mm
LB1869-C 25.4 mm 500.0 mm +2.0 514.7 mm 2.3 mm 2.0 mm 499.2 mm
LB1475-C 25.4 mm 750.0 mm +1.3 772.2 mm 2.2 mm 2.0 mm 749.3 mm
LB1409-C 25.4 mm 1000.0 mm +1.0 1029.8 mm 2.2 mm 2.0 mm 999.3 mm

Suggested Fixed Lens Mount: LMR1(/M)

  • Focal lengths are listed at the design wavelength, 587.6 nm.
  • Reciprocal of the Focal Length in Meters
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LB1761-C Support Documentation
LB1761-CN-BK7 Bi-Convex Lens, Ø1", f = 25.4 mm, ARC: 1050 - 1700 nm
$46.63
Today
LB1757-C Support Documentation
LB1757-CN-BK7 Bi-Convex Lens, Ø1", f = 30.0 mm, ARC: 1050 - 1700 nm
$46.04
Today
LB1811-C Support Documentation
LB1811-CN-BK7 Bi-Convex Lens, Ø1", f = 35.0 mm, ARC: 1050 - 1700 nm
$45.15
Today
LB1027-C Support Documentation
LB1027-CN-BK7 Bi-Convex Lens, Ø1", f = 40.0 mm, ARC: 1050 - 1700 nm
$44.85
Today
LB1471-C Support Documentation
LB1471-CN-BK7 Bi-Convex Lens, Ø1", f = 50.0 mm, ARC: 1050 - 1700 nm
$43.95
Today
LB1596-C Support Documentation
LB1596-CN-BK7 Bi-Convex Lens, Ø1", f = 60.0 mm, ARC: 1050 - 1700 nm
$43.66
Today
LB1901-C Support Documentation
LB1901-CN-BK7 Bi-Convex Lens, Ø1", f = 75.0 mm, ARC: 1050 - 1700 nm
$43.36
Today
LB1676-C Support Documentation
LB1676-CN-BK7 Bi-Convex Lens, Ø1", f = 100.0 mm, ARC: 1050 - 1700 nm
$42.47
Today
LB1904-C Support Documentation
LB1904-CN-BK7 Bi-Convex Lens, Ø1", f = 125.0 mm, ARC: 1050 - 1700 nm
$42.47
Today
LB1437-C Support Documentation
LB1437-CN-BK7 Bi-Convex Lens, Ø1", f = 150.0 mm, ARC: 1050 - 1700 nm
$41.88
Today
LB1294-C Support Documentation
LB1294-CN-BK7 Bi-Convex Lens, Ø1", f = 175.0 mm, ARC: 1050 - 1700 nm
$41.58
Today
LB1945-C Support Documentation
LB1945-CN-BK7 Bi-Convex Lens, Ø1", f = 200.0 mm, ARC: 1050 - 1700 nm
$41.58
Today
LB1056-C Support Documentation
LB1056-CN-BK7 Bi-Convex Lens, Ø1", f = 250.0 mm, ARC: 1050 - 1700 nm
$41.29
Today
LB1779-C Support Documentation
LB1779-CN-BK7 Bi-Convex Lens, Ø1", f = 300.0 mm, ARC: 1050 - 1700 nm
$40.98
Lead Time
LB1391-C Support Documentation
LB1391-CN-BK7 Bi-Convex Lens, Ø1", f = 400.0 mm, ARC: 1050 - 1700 nm
$40.98
Today
LB1869-C Support Documentation
LB1869-CN-BK7 Bi-Convex Lens, Ø1", f = 500.0 mm, ARC: 1050 - 1700 nm
$40.98
Lead Time
LB1475-C Support Documentation
LB1475-CN-BK7 Bi-Convex Lens, Ø1", f = 750.0 mm, ARC: 1050 - 1700 nm
$40.98
Lead Time
LB1409-C Support Documentation
LB1409-CN-BK7 Bi-Convex Lens, Ø1", f = 1000.0 mm, ARC: 1050 - 1700 nm
$40.70
Today
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Ø2" (50.8 mm) N-BK7 Bi-Convex Lenses (AR Coating: 1050 - 1700 nm)

Item # Diameter Focal Lengtha Diopterb Radius of Curvature Center Thickness Edge Thickness Back Focal Lengtha Reference
Drawing
LB1723-C 50.8 mm 60.0 mm +16.7 59.3 mm 14.4 mm 3.0 mm 55.0 mm Bi-Convex Lens Drawing
LB1309-C 50.8 mm 75.0 mm +13.3 75.2 mm 11.8 mm 3.0 mm 71.0 mm
LB1630-C 50.8 mm 100.0 mm +10.0 101.4 mm 9.5 mm 3.0 mm 96.8 mm
LB1106-C 50.8 mm 125.0 mm +8.0 127.4 mm 8.1 mm 3.0 mm 122.3 mm
LB1374-C 50.8 mm 150.0 mm +6.7 153.3 mm 7.2 mm 3.0 mm 147.6 mm
LB1607-C 50.8 mm 175.0 mm +5.7 179.1 mm 6.6 mm 3.0 mm 172.8 mm
LB1199-C 50.8 mm 200.0 mm +5.0 205.0 mm 6.2 mm 3.0 mm 198.0 mm
LB1889-C 50.8 mm 250.0 mm +4.0 256.6 mm 5.5 mm 3.0 mm 248.2 mm
LB1917-C 50.8 mm 300.0 mm +3.3 308.2 mm 5.1 mm 3.0 mm 298.3 mm
LB1862-C 50.8 mm 400.0 mm +2.5 411.3 mm 4.6 mm 3.0 mm 398.5 mm
LB1909-C 50.8 mm 500.0 mm +2.0 514.4 mm 4.3 mm 3.0 mm 498.6 mm
LB1247-C 50.8 mm 750.0 mm +1.3 772.0 mm 3.8 mm 3.0 mm 748.7 mm
LB1859-C 50.8 mm 1000.0 mm +1.0 1029.5 mm 3.6 mm 3.0 mm 998.8 mm

Suggested Fixed Lens Mount: LMR2(/M)

  • Focal lengths are listed at the design wavelength, 587.6 nm.
  • Reciprocal of the Focal Length in Meters
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LB1723-C Support Documentation
LB1723-CN-BK7 Bi-Convex Lens, Ø2", f = 60.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1309-C Support Documentation
LB1309-CN-BK7 Bi-Convex Lens, Ø2", f = 75.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1630-C Support Documentation
LB1630-CN-BK7 Bi-Convex Lens, Ø2", f = 100.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1106-C Support Documentation
LB1106-CN-BK7 Bi-Convex Lens, Ø2", f = 125.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1374-C Support Documentation
LB1374-CN-BK7 Bi-Convex Lens, Ø2", f = 150.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1607-C Support Documentation
LB1607-CN-BK7 Bi-Convex Lens, Ø2", f = 175.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1199-C Support Documentation
LB1199-CN-BK7 Bi-Convex Lens, Ø2", f = 200.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1889-C Support Documentation
LB1889-CN-BK7 Bi-Convex Lens, Ø2", f = 250.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1917-C Support Documentation
LB1917-CN-BK7 Bi-Convex Lens, Ø2", f = 300.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1862-C Support Documentation
LB1862-CN-BK7 Bi-Convex Lens, Ø2", f = 400.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1909-C Support Documentation
LB1909-CN-BK7 Bi-Convex Lens, Ø2", f = 500.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1247-C Support Documentation
LB1247-CN-BK7 Bi-Convex Lens, Ø2", f = 750.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
LB1859-C Support Documentation
LB1859-CN-BK7 Bi-Convex Lens, Ø2", f = 1000.0 mm, ARC: 1050 - 1700 nm
$55.08
Today
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Ø6.0 mm N-BK7 Bi-Convex Lenses (AR Coating: 1050 - 1700 nm)

Item # Diameter Focal Lengtha Diopterb Radius of Curvature Center Thickness Edge Thickness Back Focal Lengtha Reference
Drawing
LB1157-C 6.0 mm 10.0 mm +100.0 9.9 mm 2.4 mm 1.5 mm 9.2 mm Bi-Convex Lens Drawing
LB1406-C 6.0 mm 12.0 mm +83.3 12.0 mm 2.3 mm 1.5 mm 11.2 mm

Suggested Fixed Lens Mounts: LMR6(/M)

  • Focal lengths are listed at the design wavelength, 587.6 nm.
  • Reciprocal of the Focal Length in Meters
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LB1157-C Support Documentation
LB1157-CN-BK7 Bi-Convex Lens, Ø6.0 mm, f = 10.0 mm, ARC: 1050 - 1700 nm
$41.88
Today
LB1406-C Support Documentation
LB1406-CN-BK7 Bi-Convex Lens, Ø6.0 mm, f = 12.0 mm, ARC: 1050 - 1700 nm
$40.09
Today
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Ø9.0 mm N-BK7 Bi-Convex Lenses (AR Coating: 1050 - 1700 nm)

Item # Diameter Focal Lengtha Diopterb Radius of Curvature Center Thickness Edge Thickness Back Focal Lengtha Reference
Drawing
LB1494-C 9.0 mm 12.0 mm +83.3 11.7 mm 3.6 mm 1.8 mm 10.7 mm Bi-Convex Lens Drawing
LB1212-C 9.0 mm 20.0 mm +50.0 20.1 mm 2.8 mm 1.8 mm 19.0 mm

Suggested Fixed Lens Mounts: LMR9(/M)

  • Focal lengths are listed at the design wavelength, 587.6 nm.
  • Reciprocal of the Focal Length in Meters
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
LB1494-C Support Documentation
LB1494-CN-BK7 Bi-Convex Lens, Ø9.0 mm, f = 12.0 mm, ARC: 1050 - 1700 nm
$42.76
Today
LB1212-C Support Documentation
LB1212-CN-BK7 Bi-Convex Lens, Ø9.0 mm, f = 20.0 mm, ARC: 1050 - 1700 nm
$40.09
Today