Optical Mirror Selection Guide

Overview

Mirrors are probably the most commonly used optical elements in your lab, and their quality, performance, and reliability are key to the success of your experiment. That's why we provide a variety of mirrors so you can be assured to find what you need. When choosing an Optical Mirror, keep in mind the reflectivity, laser damage resistance, and coating durability. For quick delivery, all our mirrors are shipped from stock.


Metallic Coatings

Broadband metallic coated mirrors are good general-purpose mirrors because they can be used over a very broad spectral range from 450 nm to 12 µm. They are also insensitive to polarization and angle of incidence, and provide a constant phase shift, making them appropriate for ultrashort-pulse applications. Their softer coating, however, makes them more susceptible to damage, and special care must be taken when cleaning.

Dielectric Coatings

Dielectric mirrors offer higher reflectivity over a broad spectral range of a few 100 nm. Their coating is more durable, making them easier to clean, and more resistant to laser damage. We offer broadband dielectric mirrors that are ideal for general laboratory use as well as mirrors especially for high-power Nd:YAG applications at 1.064 µm and 532 nm and DUV and UV applications.

Ultrashort-Pulse Application Coatings

Dielectric mirror coatings can cause significant dispersive effects for ultrashort pulses. The dispersion of the material and the interference effects between the layers result in rapid phase variations at specific wavelengths. Since the group delay is related to the slope of the phase variation, these wavelength regions introduce significant group-delay errors that can broaden and distort your pulse. Therefore, for applications that require steering ultrashort pulses, such as those produced by Ti:Sapphire lasers, we suggest using our silver-coated mirrors, which have minimal phase distortion.

Selecting an Optical Mirror

See Optical Mirrors to shop or browse all of our standard models, or select a product family below for more information. We also offer a wide variety of Mirror Mounts.

  Metallic Coated Mirror Families Coating Types Diameters Material Clear Aperture
OP-bbmetalmirrorsgld Broadband Metallic Mirrors AL.2 (250-600 nm)
ER.1 (450-700 nm)
ER.2 (480-20,000 nm)
ER.4 (650-20,000 nm)
0.5 to 8.0 in. Pyrex® or Zerodur® ≥ central 80% of diameter
OP-utilitybbmirrors-S Utility Broadband Metallic Mirrors ER-3-S 1.0 & 2.0 in.
or Square
Float Glass
OP-concavemirrors-S Concave Broadband Metallic Mirrors AL.2 (250-600 nm)
ER.1 (450-700 nm)
ER.2 (480-20,000 nm)
0.5, 1.0 & 2.0 in. Pyrex® ≥ central 80% of diameter
OP-pinholefreemirrors-S PinholeFree™ Broadband Metallic Mirrors AL.2-PF (250-600 nm)
ER.1-PF (450-700 nm)
ER.2-PF (480-20,000 nm)
0.5, 1.0 & 2.0 in. Pyrex® ≥ central 80% of diameter
  Dielectric Coated Mirror Families Coating Types Diameters Material Clear Aperture
OP-bbdielecmirrors-S Broadband Dielectric Mirrors BD.1 (488-694 nm)
BD.2 (700-950 nm)
0.5 to 8.0 in. Pyrex® or Zerodur® ≥ central 80% of diameter
OP-laserlinemirrors-S Laser Line Dielectric Mirrors Various Laser Lines 0.5 to 8.0 in. Pyrex® or Zerodur® ≥ central 80% of diameter
OP-hi_en_plate_bs-3-S Ultra-broadband Dielectric Mirrors BB.1 (350-700 nm)
BB.2 (650-1130 nm)
BB.3 (350-1100 nm)
1.0 in. UV Grade Fused Silica ≥ central 80% of diameter
10Q20BB.HR family BroadBeamTM High Reflector Mirrors BB.HR (350-1100 nm) 1.0 in. UV Grade Fused Silica ≥ central 80% of diameter
OP-ndyagmirrors-S High-Energy Nd:YAG Laser Mirrors Various 1.0 & 2.0 in. UV Grade Fused Silica ≥ central 80% of diameter
OP-excimermirrors-S High Energy Excimer Laser Mirrors Various 1.0 & 2.0 in. UV Grade Fused Silica ≥ central 80% of diameter
LL-DeepUV-Excimer-Mirrors Long-Lived Deep UV Excimer Laser Mirrors LL.50 (193 nm, 0°)
LL.55 (193 nm, 45°)
1.0 & 2.0 in. Excimer Grade Fused Silica ≥ central 80% of diameter
OP-lolossupermirrors-S High Performance SuperMirrors™ SR.30F (583-663 nm)
SR.40F (761-867 nm)
SR.50F (996-1134 nm)
SR.60F (1241-1412 nm)
SR.70F (1457-1659 nm)
1.0 in. UV Grade Fused Silica ≥ central 80% of diameter
OP-uf25_3szs-S Low GVD Broadband Mirrors for Ultrashort Pulses UF225C-S 0.5, 1.0 & 2.0 in. Grada A N-BK7 ≥ central 80% of diameter
OP-u_fast_pump_mir-S High Reflecting Pump Mirrors for Ultrashort Pulses UF220C-S 0.5 & 1.0 in. Grada A N-BK7 ≥ central 80% of diameter
OP-SuperBB-S Super-Broadband Turning Mirrors for Ultrashort Pulses UF.35P (680-1060 nm)
UF.35S (680-1060 nm)
1.0 in. Fused Silica ≥ central 78% of diameter
  Parabolic & Ellipsoidal Mirror Families Coating Types Diameters Material Clear Aperture
FG-rep_offaxis_para_1-S Off-Axis Replicated Parabolic Mirrors Gold-AlmgF2_ref1 1.5 in. Alluminum ≥ central 90% of diameter

Reflective Coatings

Metallic Coatings Wavelength
Range
Reflectance Abrasion
Resistance
Cost Features
AL.2 250–-600 nm Ravg >90% Moderate Low UV Reflectivity is enhanced by
a MgF2 overcoat
AL-1-S 400–-700 nm Ravg >88% Moderate Low Visible reflectivity is enhanced by a
protective SiO overcoat
ER-1-S 450–-700 nm Ravg >93% Moderate Low Visible and NIR reflectivity is enhanced
by a multilayer dielectric overcoat
ER-2-S 480-–20,000 nm Ravg >96% Moderate Low Visible and IR performance superior
to aluminum coatings
ER-4-S 65–0-20,000 nm Ravg >96% Moderate Low NIR to Infrared performance
slightly higher than protected silver
Dielectric Coatings Wavelength
Range
Reflectance Abrasion
Resistance
Cost Features
BD-1-0-S 488-–694 nm Rs, Rp >98–99% High Moderate Very high reflectivity over a broad
wavelength range
BD-20T-S 700–-950 nm Rs, Rp >98–99% High Moderate Very high reflectivity over a broad
wavelength range
BD-20T-S 700-–950 nm Rs, Rp >98–99% High Moderate Very high reflectivity over a broad
wavelength range
Ultra-broadband Dielectric Mirror, BB.1 Coating 350-700 nm Rs, Rp >99% High Moderate Special coating design to withstand higher damage threshold
Ultra-broadband Dielectric Mirror, BB.2 Coating 650-1130 nm Rs, Rp >99% High Moderate Special coating design to withstand higher damage threshold
Ultra-broadband Dielectric Mirror, BB.3 Coating 350-1100 nm Rs, Rp >99% High Moderate Special coating design to withstand higher damage threshold
DM-4TY-S Various
325-–1550 nm
Rs, Rp >99% High Moderate Very high reflectivity over a narrow
wavelength range
EM-X5-S 193, 248,
308, 352 nm
Rs >99.7%,
Rp >99%
High High High reflectivity and damage threshold
at excimer laser wavelengths
MI1045-DY HR 532nm 266, 354.7,
532, 1064 nm
Rs, Rp >99% High High High reflectivity and damage threshold
at Nd:YAG laser wavelengths
SB145-S 485–-700 nm
700–-910 nm
Rs, Rp >99.9% Low High Highest reflectivity broadband
mirror commercially available
UF225C-S Various
700–-930 nm
Rs, Rp >99% High High High reflecting pump mirrors, output
couplers, and broadband mirrors
with minimum pulse dispersion

Substrate Materials

We chose Pyrex® material for our substrates because it offers a lower thermal-expansion coefficient than N-BK7 optical glass and polishes more easily than fused quartz. Because the Pyrex substrate has inhomogeneities in its refractive index, these mirrors are not suited for transmissive applications. We fine-grind the backside of the substrates to prevent inadvertent transmissions. All the edges are chamfered to avoid chipping during use. When high stability is critical, Zerodur® is the best choice for its zero thermal expansion. UV fused silica has a thermal expansion coefficient lower than Pyrex® but is more expensive. Because of its excellent transmissive properties, UV fused silica is often reserved for transmissive mirrors as well as high-energy laser mirrors. Please see Optical Materials for more information.

Material Coefficient of
Thermal Expansion
Cost Features
Pyrex® 3.25 x 10-6/°C Low Best all around mirror substrate, low expansion borosilicate glass,
resistant to thermal shock
UV Fused Silica 0.52 x 10-6/°C High Low thermal expansion for excellent stability, high laser damage resistance
Zerodur® 0 ± 0.1 x 10-6/°C Moderate Nominally zero thermal expansion for ultra-high stability,
unique glass-ceramic material

Optical Surfaces

Surface Quality

The surface quality of an optic is described by its surface figure and irregularity. Surface figure is defined as peak-to-valley deviation from flatness, including any curvature (also known as power) present. Surface irregularity is represented by the peak-to-valley deviations when power is subtracted. Our front-surface figure is typically guaranteed flat to less than λ/10 at 633 nm over the clear aperture. Our 2" mirrors have a typical figure of λ/4 over the clear aperture. When preservation of wavefront is critical, choose a flatness of λ/10 or better.

As for surface quality, the smaller the scratch-dig specification, the lower the scatter. Our metal mirrors offer a scratch-dig of 25-10; our dielectric mirrors, 15-5; and our UV mirrors, 10-5, which is ideal for the most demanding laser systems where low scatter is critical.

Dig: a defect on the surface of an optic as defined in average diameter in 1/100 of a millimeter.

Scratch: a defect on an optic that is many times longer than it is wide.

Selecting the proper mirror for your application requires making a number of choices. A few of the many considerations include: reflectivity, laser damage resistance, coating durability, thermal expansion of the substrate, wavefront distortion, scattered light, and certainly cost. The following tables should help in comparing the available choices from Newport.

The mirror application drives the requirements for surface flatness and surface quality. When preservation of wavefront is critical, a λ/10 to λ/20 mirror should be selected; when wavefront is not as important as cost, a λ/2 to λ/5 mirror can be used. For surface quality, the tighter the scratch-dig specification, the lower the scatter. For demanding laser systems, 20-10 to 10-5 scratch-dig is best. For applications where low scatter is not as critical as cost, 40-20 to 60-40 scratch-dig can be used.  Please see Opical Surfaces for more information.

Surface Flatness

Figure Cost Applications
λ/2 Low Used where wavefront distortion is not as important as cost
λ/5 Moderate Excellent for most general laser and imaging applications where low wavefront performance must be balanced with cost
λ/10 Moderate For laser and imaging applications where low wavefront distortion, especially in systems with multiple elements
λ/20 High For the most demanding laser systems where maintaining accurate wavefront is critical to performance

Surface Quality

Scratch-Dig Cost Applications
60-40 Low Used for low-power laser and imaging applications with unfocused beams where scatter is not critical
40-20 Moderate Ideal for laser and imaging applications with collimated beams where scatter begins to affect system performance
20-10 High Excellent for laser systems with focused beams that can tolerate little scattered light
10-5 High For the most demanding laser systems where low scatter is critical to performance