Optical Coatings

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Fundamental Optics Material Properties Optical Specifications Gaussian Beam Optics HEBBAR Coatings Our HEBBAR (high-efficiency broadband antireflection) coatings provide a very low reflectance over a broad spectral bandwidth. These multilayer films, comprising alternate layers of various index materials, are combined to reduce overall reflectance to an extremely low level for the broad spectral range covered. These coatings exhibit a characteristic, double-minimum reflectance curve covering a range of some 300 nm in wavelength. The reflectance does not exceed 1.0% and is more typically below 0.6% over this entire range. Within a more limited spectral range on either side of the central peak, reflectance can be held well below 0.4%. HEBBAR coatings are somewhat insensitive to angle of incidence. The effect of increasing the angle of incidence, however, is to shift the curve to slightly shorter wavelengths and to increase the long wavelength reflectance slightly. These coatings are extremely useful for high-numerical-aperture (low f-number) lenses or steeply curved surfaces. In these cases, incidence angle varies significantly over aperture. Six versions of HEBBAR coatings are offered (see figures 5.20 through 5.25). Many of our components are carried in stock with a HEBBAR coating. The /078 covers most of the visible spectrum (415–700 nm) and is optimized for normal incidence. A 45-degreeincidence version of this coating (/079) is available. The infraredshifted /077 covers the range from 700 nm to 1100 nm. Two HEBBAR coatings, the /075 and the /076, are specifically optimized for diode laser wavelengths. The /074 is a modified HEBBAR coating intended for use in the range from 300 nm to 500 nm. Over this range, the reflectance is less than 1% and typically does not exceed 0.5%. Due to the special nature of the /074 coating, it is designed to be used only at an angle of incidence of 0±15 degrees, and it is not suitable for use on lenses with steeply curved surfaces. For these coatings, reflectance values apply to indices 1.47–1.55 only. Other indices, while having their own designs, will have reflectance values approximately 20% higher for incidence angles from 0 to 15 degrees and 25% higher for incidence angles of 30 degrees. The typical reflectance curves shown for the HEBBAR coatings are for BK7 substrates, except for /074 which is for fused silica. HEBBAR Coatings Wavelength Range (nm) 440–660 415–685 415–700 415–680 632.8 632.8 425–670 425–670 440–670 440–670 750–1100 700–1100 700–1150 700–1100 650–850 650–850 780–850 780–850 725–875 300–500 300–500 Maximum Reflectance (%) 0.6 Abs 0.4 Avg 1.0 Abs 1.0 Abs 0.3 Abs 0.4 Abs 0.6 Avg 1.0 Abs 0.4 Abs 1.0 Abs 0.6 Abs 0.4 Avg 1.0 Abs 1.0 Abs 0.6 Avg 1.0 Abs 0.25 Abs 0.40 Abs 1.0 Abs 1.0 Abs 0.5 Avg Angle of Incidence (degrees) 0–15 0–15 0–15 0–30 0–15 0–30 45 45 30–45 45–50 0–15 0–15 0–15 0–30 0–15 0–15 0–15 0–30 0–30 0–15 0–15 COATING SUFFIX /078 /079 /077 /075 /076 /074 Note: To order, append coating suffix to product number and specify which surfaces are to be coated. Optical Coatings 5.18 1 Visit Us OnLine! www.mellesgriot.com
PERCENT REFLECTANCE 5 4 3 2 1 normal incidence 45° incidence typical reflectance curves 400 500 600 700 WAVELENGTH IN NANOMETERS Figure 5.20 HEBBAR coating for visible /078 $ Industry-standard multilayer, AR coating for 415 to 700 nm $ Excellent performance with HeNe and visible diode lasers $ Optimized for normal incidence $ R avg < 0.4%, R abs < 1.0% $ Damage threshold: 3.8 J/cm 2 810%, 10-nsec pulse (230 MW/cm 2 ) at 532 nm PERCENT REFLECTANCE 5 4 3 2 1 45° incidence 400 500 600 700 WAVELENGTH IN NANOMETERS Figure 5.21 HEBBAR coating for visible /079 typical reflectance curve $ Optimized for 425–670 nm at 45-degree incidence $ Perfect for plate beamsplitting applications $ R avg < 0.6%, R abs < 1.0% $ Damage threshold: see /078 (similar specifications) PERCENT REFLECTANCE PERCENT REFLECTANCE 5 4 3 2 1 5 4 3 2 1 normal incidence 45° incidence typical reflectance curves 700 800 900 1000 1100 1200 WAVELENGTH IN NANOMETERS Figure 5.22 HEBBAR coating for near-infrared /077 $ Covers popular Ti:sapphire and diode laser wavelengths: 750 to 1100 nm $ R avg < 0.4%, R abs < 0.6% $ Damage threshold: 6.5 J/cm 2 810%, 20-nsec pulse (260 MW/cm 2 ) at 1064 nm normal incidence 45° incidence typical reflectance curves 500 550 600 650 700 750 800 850 900 WAVELENGTH IN NANOMETERS Figure 5.23 HEBBAR coating for near-infrared and diode wavelengths /075 $ Optimized for performance from 660 to 835 nm $ Versatile for use with most diode lasers from visible to near-infrared wavelengths $ R avg < 0.5%, R abs < 1.0% $ Damage threshold: see /078 (similar specifications) Fundamental Optics Gaussian Beam Optics Optical Specifications Material Properties Optical Coatings Visit Us Online! www.mellesgriot.com 1 5.19
Page 1 and 2:
Fundamental Optics 1 Introduction 1
Page 3 and 4:
Paraxial Formulas SIGN CONVENTIONS
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object F 2 Figure 1.4 image Example
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Figure 1.6 Figure 1.7 f f 2 object
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Figure 1.8 Figure 1.9 INDIVIDUAL EL
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Performance Factors After paraxial
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third-order, monochromatic, spheric
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Positive lens elements usually have
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Lens Shape Aberrations described in
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ay f-numbers 2.7 3.3 4.4 6.7 13.3 S
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AIRY DISC DIAMETER = 2.44 l f/# Fig
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Lens Selection Having discussed the
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Example 4: Diffraction-Limited Perf
Page 27 and 28:
Aberration Balancing To improve sys
Page 29 and 30:
Definition of Terms FOCAL LENGTH (f
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infinity (which is a comfortable vi
Page 33 and 34:
For symmetric lenses (r 2 = 4r 1 ),
Page 35 and 36:
Separation of Nodal Point from Corr
Page 37 and 38:
Gaussian Beam Optics 2 Introduction
Page 39 and 40:
Even if a Gaussian TEM 00 laser-bea
Page 41 and 42: eam expander INCORPORATING M 2 INTO
Page 43 and 44: M 2 AND THE LENS EQUATION For real-
Page 45 and 46: employed when laser power must be c
Page 47 and 48: Figure 2.13 Keplerian beam expander
Page 49 and 50: Optical Specifications 3 Wavefront
Page 51 and 52: Centration The mechanical axis and
Page 53 and 54: PERFECT RECTANGULAR LENS The MDMTF
Page 55 and 56: The permissible number of maximum-s
Page 57 and 58: Material Properties 4 Material Prop
Page 59 and 60: Introduction Glass manufacturers pr
Page 61 and 62: maximum value for homogeneity withi
Page 63 and 64: Melles Griot Lens Materials Melles
Page 65 and 66: Refractive Index of Five Schott Gla
Page 67 and 68: Synthetic Fused Silica Fused silica
Page 69 and 70: PERCENT INTERNAL TRANSMITTANCE 99.9
Page 71 and 72: Low-Expansion Borosilicate Glass Th
Page 73 and 74: ZERODUR ® Many optical application
Page 75 and 76: Optical Coatings 5 Optical Coatings
Page 77 and 78: OEM and Special Coatings Melles Gri
Page 79 and 80: PERCENT REFLECTANCE 100 90 80 70 60
Page 81 and 82: will depend on the ratio of optical
Page 83 and 84: v = angle of incidence PERCENT REFL
Page 85 and 86: PERCENT REFLECTANCE PER SURFACE 2.0
Page 87 and 88: Two-Layer Coatings of Arbitrary Thi
Page 89 and 90: ION-ASSISTED BOMBARDMENT Ion-assist
Page 91: Single-Layer MgF 2 Antireflection C
Page 95 and 96: EXTENDED-RANGE HEBBAR ANTIREFLECTIO
Page 97 and 98: V-Coatings V-coatings are multilaye
Page 99 and 100: Metallic High-Reflection Coatings W
Page 101 and 102: INTERNAL SILVER (/036) $ For intern
Page 103 and 104: Dielectric High-Reflection Coatings
Page 105 and 106: PERCENT REFLECTANCE 100 80 60 40 20
Page 107 and 108: MAXBRIte Coatings MAXBRIte (multi
Page 109 and 110: Laser-Line MAX-R Coatings These mu
Page 111 and 112: Ultrafast Coating Melles Griot has
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Optical Coatings

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