Melles Griot Melles Griot Optics Guide
Melles Griot    Optical Coatings    Antireflection (AR) Coatings    HEBBAR™ Coatings  
Antireflection (AR) Coatings

Standard HEBBAR™ Coatings

Melles Griot 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 standard HEBBAR coatings are available. Many of our components are carried in stock with a HEBBAR coating. For these coatings, the reflectance values given below apply only to substrates with refractive indices ranging from 1.47 to 1.55. 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 below are for BK7 substrates, except for the /072 and /074 coaingwhich is for fused silica.

To order a HEBBAR coating, append the coating suffix to the product number and specify which surfaces are to be coated.
/078 HEBBAR™ Coating for Visible Wavelengths
The /078 is the industry-standard multilayer AR coating for visible optics. It covers the visible spectrum from 415 to 700 nm and is optimized for normal incidence. It provides excellent performance with HeNe and visible diode lasers.
Optics Figure
HEBBAR™ normal-incidence coating for visible wavelengths /078

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
440-660 0.6 Abs 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
415-685 0.4 Avg 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
415-700 1.0 Abs 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
415-680 1.0 Abs 0-30 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
632.8 0.3 Abs 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
632.8 0.4 Abs 0-30 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm

/079 HEBBAR™ Coating for Visible Wavelengths
This is a 45-degree-incidence version of the /078 coating shown above. It is optimized for 425 to 670 nm and is perfect for beamsplitting applications.
Optics Figure
HEBBAR™ 45° coating for visible wavelengths /079

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
440-660 0.6 Abs 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
425-670 1.0 Abs 45 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
440-670 0.4 Abs 30-45 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
440-670 1.0 Abs 45-50 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm

/077HEBBAR™ Coating for Near Infrared
The infrared-shifted /077 covers the range from 700 nm to 1100 nm, which includes the popular Ti:sapphire and diode laser wavelengths.
Optics Figure
HEBBAR™ coating for near infrared /077

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
750-1100 0.6 Abs 0-15 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm
700-1100 0.4 Avg 0-15 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm
700-1150 1.0 Abs 0-15 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm
700-1100 1.0 Abs 0-30 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm

/075 HEBBAR™ Coating for Near Infrared and Diode Wavelengths
The /075 HEBBAR coating is optimized for performance from 660 to 835 nm. It is versatile for use with most diode lasers from visible to the near-infrared wavelengths.
Optics Figure
HEBBAR™ coating for near infrared and diode wavelengths /075

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
650-850 0.6 Avg 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm
650-850 1.0 Abs 0-15 3.8 J/cm2 ± 10%,
10-nsec pulse (230 MW/cm2) at 532 nm

/076 HEBBAR™ Coating for Diode Lasers
The /076 coating is optimized for diode laser wavelengths ranging from 780 to 850 nm.
Optics Figure
HEBBAR™ coating for near infrared and diode wavelengths /076

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
780-850 0.25 Abs 0-15 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm
780-850 0.40 Abs 0-30 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm
725-875 1.0 Abs 0-30 6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm

/074 HEBBAR™ Coating for Ultraviolet
The /074 is a modified HEBBAR coating intended for use in the range from 300 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.
Optics Figure
HEBBAR&tm; coating for ultraviolet /074

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
300-500 1.0 Abs 0-15 3.2 J/cm2 ± 10%,
10-nsec pulse (260 MW/cm2) at 355 nm
on silica substrate
300-500 0.5 Avg 0-15 3.2 J/cm2 ± 10%,
10-nsec pulse (260 MW/cm2) at 355 nm
on silica substrate

Extended-Range HEBBAR™ Antireflection Coatings
Many optical systems require transmission of several, quite disparate wavelengths or transmission over a very broad continuum of wavelengths. Examples include systems involving two types of lasers, a laser system producing fundamental and harmonic wavelengths, a multiple-wave mixing experiment, stimulated Raman experiments, or a system using one laser for action and another for alignment.

In these situations, normal broadband coatings will not suffice. For such cases, Melles Griot makes available extended-range antireflection coatings. These coatings offer either a single extended performance band or two separate high-performance regions. In the latter case, one of the low-reflectance regions can be quite narrow, since many of the applications often involve at least one laser beam. Melles Griot manufactures many such coatings for a variety of customer specifications. The following special coatings are offered as standard catalog items. The typical reflectance curves shown for the extended-range HEBBAR coatings are for BK7 substrates, except for /072 which is for fused silica.
/083 HEBBAR™ Visible/1064 nm Coating
This coating, designated /083 is designed for broadband antireflectance in the visible, as well as at 1064 nm, the wavelength of Nd-YAG lasers. With less than 1% reflectance between 450 and 680 nm, and less than 0.25% reflectance at 1064 nm, this coating will find many uses in any system using a visible source in conjunction with low to moderate power Nd:YAG laser fundamental radiation. Its high performance is guaranteed for incidence angles up to 15 degrees. Optics with this coating are therefore best used at normal incidence and can be used for both converging and diverging beams.
Optics Figure
HEBBAR™ coating for visible and Nd:YAG wavelengths /083

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Average
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
450-700 1.25 <1.0 0-15 1.3 J/cm2 ± 10%,
10 nsec pulse (107 MW/cm2) at 532 nm
1064 0.25 <1.0 0-15 5.4 J/cm2 ± 10%,
20 nsec pulse (220 MW/cm2)at 1064 nm

/084 HEBBAR™ Diode Laser Coating
This coating, designated /084 is designed to operate at two popular diode laser wavelengths. It is a modified broadband coating which works well through the near-infrared spectrum with reflection minima between 780 nm and 830 nm and also at 1300 nm. Performance is guaranteed for incidence angles up to 15 degrees. This coating can therefore be used even without complete collimation of the diode radiation.
Optics Figure
HEBBAR™ coating for IR diode lasers /084

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Average
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
780-830 0.5 <0.4 0-15 1.3 J/cm2 ± 10%,
10 nsec pulse (107 MW/cm2) at 532 nm
1300 0.5 <0.4 0-15 5.4 J/cm2 ± 10%,
20 nsec pulse (220 MW/cm2) at 1064 nm

/073 HEBBAR™ Extended Broadband Coating
This very broad coating, designated /073, offers good performance over the entire visible and near-infrared spectral range. It is effective with broadband infrared sources, such as infrared LEDs, as well as systems using several, widely separated discrete laser lines.
Optics Figure
HEBBAR&tm; coating for visible and near-IR /073

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Average
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
420-1100 1.75 <1.0 0-15 4.5 J/cm2 ± 10%,
10-nsec pulse 358 MW/cm2) at 532 nm
6.5 J/cm2 ± 10%,
20-nsec pulse (260 MW/cm2) at 1064 nm

/072 HEBBAR™ UV Broadband Coating
The ultraviolet broadband antireflection coating, designated /072, is designed for use on fused-silica substrates and provides less than 1% reflectance from 245 nm to 440 nm. It is particularly useful with most popular excimer laser lines, as well as other ultraviolet sources, such as mercury lamps. The broad response of this coating allows it to perform well even with poorly collimated light, which can be especially advantageous when dealing with excimer laser sources.
Optics Figure
HEBBAR™ coating for UV /072

 
Wavelength
Range
(nm)		 Maximum
Reflectance
(%)		 Average
Reflectance
(%)		 Angle of
Incidence
(degrees)		 Damage
Threshold
245-440 1.0 <0.5 0-15 3.5 J/cm2 ±10%,
10-nsec pulse (280 MW/cm2) at 355 nm
on silica substrate

  Back to Top Previous    Next  

Optics Guide Copyright 2002 Melles Griot Inc.