Integrating Spheres - Spectroscopic

1354
Spectroscopy Instruments
MONOCHROMATORS
SPECTROGRAPHS
ARRAY
DETECTORS
MINISPECTROMETERS
Oriel Integrating Spheres
Integrating spheres are ideal optical diffusers; they are used for
radiometric measurements where uniform illumination or angular
collection is essential, for reflectance and transmittance
measurements, or even to mix two light sources. We offer five
families of integrating spheres in sizes from 2 to 8 inches (51 to
203 mm), with three coating types to cover the following
spectral ranges:
• Barium Sulfate for 350 – 1300 nm
• PTFE for 250 – 2500 nm
• Diffuse Gold for 7.5 – 10 mm
How Do Integrating Spheres Work?
Fig. 1 shows the principle of operation of integrating spheres.
Light is collected by an integrating sphere and uniformly
reflected and scattered around the sphere’s interior so the output
is a uniform, spatially integrated field (Lambertian) of radiation
which is insensitive to the spatial, angular and polarization
changes of the input. Our integrating spheres come with 1.5 Inch
Series input and output flanges so they can be mounted to any
of our Oriel instruments and components.
Integrating Spheres
• Ideal diffusers; ensure reproducible
radiometric measurements
• Spatially insensitive collection of energy
• Uniform radiance/irradiance fields for test of sensors
• 2 to 8 inch sphere sizes
• Coated with broadband, stable coatings: PTFE
(250 – 2500 nm), BaSO 4 (350 - 1300 nm), Gold (7.5 - 10 mm)
Why an Integrating Sphere?
For critical radiometric measurements, always use an integrating
sphere; they are close to ideal diffusers. Integrating spheres are
considerably more expensive, and suffer similar or higher throughput
losses than disk diffusers, but they provide a true cosine response
and very repeatable uniform illumination of a spectrometer grating or
detector. Disk diffusers are suitable for applications requiring
relatively uniform illumination, such as detectors which are not
uniformly sensitive across the photosensitive area.
High Reflectance
Most of our integrating spheres are available with a choice of
three interior materials. For VIS-NIR applications choose our
barium sulfate-based white coated spheres. The coating is highly
reflective, >97% in the visible.
For UV, VIS or NIR measurements, we offer spheres with interiors
machined from a unique PTFE thermoplastic material that is very
rugged and highly reflective down to 250 nm. For applications in
the NIR and IR regions our diffuse gold spheres provide nearlambertian
characteristics and reflectance values up to 95%. All of
our spheres are designed to provide high reflectance, stability and
low throughput loss over their usable wavelength range.
High Damage Threshold
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INPUT
OUTPUT
DIFFUSING
BAFFLE
Fig. 1 Principle of operation of an integrating sphere. The incoming beam
is diffusely reflected inside an integrating sphere. The output port cannot
“see” the region of first impact.
The excellent reflectance of our spheres gives them a high
damage threshold. Measurements with a pulsed laser at 1.6 mm
showed the damage threshold of the coated spheres to be 1.5 W
cm -2 . The PTFE spheres have an even higher damage threshold
of 8 W cm -2 , and the gold spheres exhibit a damage threshold of
19 W cm -2 .
REFLECTANCE (%)
100
90
REFLECTANCE
80
PTFE
70
60
REFLECTANCE
50
BaSO 4
40
30
THROUGHPUT
PTFE
20
THROUGHPUT
10
BaSO 4
0
250 500 750 1000 1250 1500 1750 2000 2250 2500
WAVELENGTH (nm)
Fig. 2 Reflectance and throughput of 4 inch PTFE and BaSO 4 Spheres.
THROUGHPUT (%)
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Spectroscopy Instruments
1355
REFLECTANCE (%)
100
98
96
94
92
90
5 6 7 8 9 10
WAVELENGTH (µm)
Fig. 3 Reflectance of Diffuse Gold
Which Sphere Do I Choose?
GOLD
We offer five integrating sphere designs with a choice of interior
coatings covering the UV-VIS through the IR. Your choice is often
a tradeoff between throughput and uniformity needs. For
example, our 8 inch spheres give the most uniform output, but
suffer the greatest throughput losses due to the large diameter
of the sphere.
Monochromator Spheres
• 2 inch interior diameter spheres designed for uniform
monochromator, sensor and spectrograph illumination for
VIS and NIR.
• Also used at the output of a monochromator, to uniformly
illuminate a single detector or more than one detector.
These spheres have excellent diffusing properties, proper
baffling to prevent "first strike" radiation from entering the
instrument. 1.5 Inch Series flanges and a 1/4-20 tapped hole
facilitate mounting.
Fiber Optic Spheres
• 4 inch interior diameter integrating spheres for uniform
illumination of fiber bundles, or creating a lambertian
source with single or multiple fiber inputs
• Accept SMA fiber adapters (for ST adapters, contact a
Sales Engineer)
These spheres are a smaller version of the General Purpose
Sphere. They are 4 inches in diameter, suitable for small light
beams. There are three ports on the equator; two have 11 mm
internal diameters to fit any Oriel Fiber Bundle directly. For SMA
terminated fibers you will also need the 70463 Adapter. The third
port is a 1.5 Inch Series male flange.
General Purpose Spheres
• Available in 4 inch and 6 inch interior diameter sizes
• High lambertian diffuse coating
These General Purpose Integrating Spheres are 4 and 6 inches
(102 and 152 mm) in diameter. They include standard Oriel 1.5 Inch
Series flanges and 1/4-20 tapped holes for rod mounting. If you
need to couple these spheres to instruments with male flanges
(such as a monochromator), order the 77829 Coupling Ring. A
diagram of the light path for the 70451 is shown in Fig. 1.
Uniform Light Source Spheres
• 8 inch interior diameter
• 2 inch diameter output port
• For critical uniform illumination applications
• Turn a light source into an almost perfectly uniform
Lambertian emitter
Place one of these integrating spheres at the output of a light
source and you have an almost perfectly uniform Lambertian,
broadband source. Typical radiance uniformity is within 1-2% of
the average over the 2 inch (51 mm) diameter exit port as long as
the FOV of the imaging system stays on the baffle within the
sphere. Irradiance uniformity at the port is also better than 1-2%.
For a tunable, uniform light source, couple the sphere to the
input of a monochromator (or motorized filter wheel). You'll need
the 77829 Coupling Ring to attach one of these to an Oriel
Monochromator. To make a uniform calibration source with
several orders of luminance range, attach a filter wheel with
neutral density filters to the sphere's input. The input port of the
sphere has a 1.5 Inch Series male flange so it can be mated to an
Oriel Light Source. The output port is a 2 inch (51 mm) diameter
port frame for simple mounting of samples.
Reflectance and Transmittance Spheres
• 8 inch interior diameter spheres
• For measurements of specular and diffuse hemispherical
reflectance and total transmittance
The 70679 and 70682 are for measurement of specular and
diffuse hemispherical reflectance and total transmittance using a
8/D geometry (8 degree beam incidence/Diffuse collection). The
70679 is good for the VIS-NIR regions and the 70682 is good for
UV-VIR-NIR (Note the ID of the 70682 is ~7.0”). The spheres
have 5 ports:
• Input port with 1.5 inch series male flange
• 1.0 Inch sample port, in-line with input port
• Detector port with 1.5 inch series male flange
MONOCHROMATORS SPECTROGRAPHS ARRAY
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MINISPECTROMETERS FT-IR
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• Accept a variety of port plugs and detector adapters
• 1.0 inch specular exclusion/inclusion port (for light trap or plug)
• Ideal for universal measurements and mixing two inputs for
lambertian sources
• Additional 2.0 inch port at north pole for comparison
measurement technique or center mounted samples
(custom holder required; contact a Sales Engineer with your
sample requirements).
SPECTROMETER
ACCESSORIES
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1356
Spectroscopy Instruments
MONOCHROMATORS
SPECTROGRAPHS
ARRAY
DETECTORS
A reflectance sample holder with 1 inch (25 mm) diameter,
0.5 inch (13 mm) deep cell holds the sample at 8° to the beam.
The clear aperture is 0.7 inch (18 mm). The holder is spring
loaded so that square, rectangular or irregular shapes with
dimensions up to 2 inches (51 mm) can be held against the
sphere wall. (The sample must fill the aperture.) The spring
loading allows you to quickly insert and remove the sample and
the 70496 White Spectral Calibration Disk. Light, which is
reflected from the sample strikes the port and is turned 8
degrees to the specular exclusion port. If a plug is at the
exclusion port, the light is re-captured in the sphere (specular
inclusion – total reflectance 8/D). If a light trap is used in the
exclusion port, the specular portion of the sample’s reflectance is
subtracted from the measurement (Specular excluded – diffuse
only reflectance 8/D– allows characterization of “gloss”). One
exclusion port plug is included with the sphere and one extra
port plug is included for the north pole port.
Conversely, if the 0° Sample Holder (also included with the
70679 and 70682 R/T Spheres) is used at the sample port and
the input beam is placed behind the sample port, then you can
qualify diffuse, normal or total transmittance of samples. If a plug
is used at the 1.0 inch port opposite the sample (former input
port), then all energy is included in the measurement (total
transmittance). If a light trap is used at this port opposite the
sample, then the normal transmitted beam (specular
transmission) is excluded by the trap (diffuse or normal excluded
transmittance – allows “haze” characterizations).
Ordering Information
Integrating Spheres
White Spectral Calibration Disk
The 70496 is a 1.25 inch (30 mm) diameter, 11 mm thick white
Zenith ® disk, for spectral calibration purposes. It has >95%
reflectance from 250 to 2500 nm (>98% from 400-1800 nm), is
durable, and is an almost perfect reflecting Lambertian diffuser. It
may be lightly abraded to restore performance if it becomes
dirty. The measured Hemispherical Reflectance Factor from 250
to 2500 nm is supplied for each disk. This calibration data is
traceable to NIST.
Accessories
Model
Description
70650 Port Plug, Barium Sulfate Coating, 0.5 inch
70651NS
Port Plug, Barium Sulfate Coating, 1.0 inch
70652 Port Plug, Barium Sulfate Coating, 1.5 inch
70653 Port Plug, Barium Sulfate Coating, 2.0 inch
70654 Port Plug, PTFE Coating, 0.5 inch
70655 Port Plug, PTFE Coating, 0.5 inch
70656NS
70657NS
Port Plug, PTFE Coating, 1.5 inch
Port Plug, PTFE Coating, 2.0 inch
70658 Port Plug, Diffuse Gold Coating, 0.5 inch
70659 Port Plug, Diffuse Gold Coating, 1.0 inch
70660 Port Plug, Diffuse Gold Coating, 1.5 inch
70661 Port Plug, Diffuse Gold Coating, 2.0 inch
70463 Port Adapter, SMA Terminated Fiber
70496 White Spectral Calibration Disk,
Reflectance/Transmittance Spheres
77829 Light Source Coupling Ring, 1.5 Inch Series, Double Female,
Set Screw
MINISPECTROMETERS
FT-IR
SPECTROMETERS
Model
Description
70665 Monochrometer Integrating Sphere, PTFE 250-2500 nm, 2 inch, (2) 1/2 inch Ports
70666 Monochrometer Integrating Sphere, Barium Sulfate 360-700 nm, 2 in, (2) 1/2 in Ports
70667 Monochrometer Integrating Sphere, Diffuse Gold 7.5-10mm, 2 in,(2)1/2 in Ports
70668 Fiber Optic Integrating Sphere, Barium Sulfate 360-700 nm, 4 in, (3) 1 in Ports
70669 Fiber Optic Integrating Sphere, PTFE 250-2500 nm, 4 inch, (3) 1 inch Ports
70670 Fiber Optic Integrating Sphere, Diffuse Gold 7.5-10 mm, 4 in, (3)1 in Ports
70671 General Purpose Integrating Sphere, Barium Sulfate 360-700 nm, 4 in, (3) 1 in Ports
70672 General Purpose Integrating Sphere, PTFE 250-2500 nm, 4 inch, (3) 1 inch Ports
70673 General Purpose Integrating Sphere, Diffuse Gold 7.5-10mm,4 in, (3)1 in Ports
70674 General Purpose Integrating Sphere, Barium Sulf. 350-1300 nm, 6 in, 3 1.5 in Ports
70675 General Purpose Integrating Sphere, PTFE 250-2500 nm, 6 in, (3) 1.5 in Ports
70676 General Purpose Integrating Sphere,Diffuse Gold 7.5-10mm,6 in,(3)1.5 in Ports
70677 Uniform Source Integrating Sphere, Barium Sulfate 350-1300 nm, 8 in, (3) 2 in Ports
70678 Uniform Source Integrating Sphere, Diffuse Gold 7.5-10 mm, 8 in, (3) 2 in Ports
70679NS
Reflectance/Transmittance Sphere, Barium Sulfate 360-700 nm, 8 in, (5) 1&2 in Ports
70682NS
Reflectance/Transmittance Sphere, PTFE 250-2500 nm, 8 in, (5) 1&2 in Ports
*PTFE spheres aren’t coated; they are machined from a thermoplastic material.
SPECTROMETER
ACCESSORIES
Phone: 1-877-835-9620 • Fax: 1-949-253-1680

Spectroscopy Instruments
1357
Fig 4 Dimensional diagram of Monochromator Integrating Spheres.
70668 BARIUM SULFATE
70670 DIFFUSE GOLD
6.23
(158.2)
4.23
(107.4)
FIBER OPTIC INTEGRATING SPHERES
PORT
PLUG
4.45
(113)
70669 PTFE
4.45
(113)
4.45
(113)
MONOCHROMATORS SPECTROGRAPHS ARRAY
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11 mm
FERRULE
ADAPTER
11 mm
FERRULE
ADAPTER
1.5 INCH
SERIES
MALE
FLANGE
1/4-20
TAPPED
HOLE
2.44
(61.9)
Fig 5 Dimensional diagram of Fiber Optic Integrating Spheres.
1.5 INCH
SERIES
MALE
FLANGE
1/4-20
TAPPED
MOUNTING
HOLE
2.80
(71.1)
MINISPECTROMETERS FT-IR
SPECTROMETERS
Fig 6 Dimensional diagram of General Purpose Integrating Spheres.
SPECTROMETER
ACCESSORIES
Email: sales@newport.com • Web: newport.com

1358
Spectroscopy Instruments
70677 BARIUM SULFATE
70678 DIFFUSE GOLD
MONOCHROMATORS
8.73
(222)
8.23
(209)
1.5 INCH
SERIES
MALE
FLANGE
2.0 INCH
APERTURE
WITH
MOUNTING
HOLES
LIGHT BAFFLE
SPECTROGRAPHS
4.39
(111.5)
1/4-20
TAPPED
HOLE
PORT
PLUG
Fig 7 Dimensional diagram of Uniform Sources Integrating Spheres.
ARRAY
DETECTORS
LIGHT
TRAP
PORT
PLUG
INTER-
CHANGEABLE
PORT
PLUG
INPUT
BEAM
70679 BARIUM SULFATE AND
70682PTFE R/T SPHERE IN
“TOTAL HEMISPHERICAL”
REFLECTANCE MODE
1.5 INCH
SERIES
MALE
1/4-20 FLANGE
TAPPED
HOLE
SAMPLE
HOLDER
LIGHT
TRAP
PORT
PLUG
PORT
PLUG
70679 BARIUM SULFATE AND
70682 PTFE R/T SPHERE IN
“TOTAL HEMISPHERICAL”
TRANSMITTANCE MODE
INTERCHANGEABLE
1.5 INCH
SERIES
MALE
1/4-20 FLANGE
TAPPED
HOLE
SAMPLE
HOLDER
INPUT
BEAM
MINISPECTROMETERS
Fig 8 Diagram of Reflectance/Transmittance Integrating Spheres.
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Phone: 1-877-835-9620 • Fax: 1-949-253-1680