Reflectance and Transmission Spectroscopy
Reflectance and transmission spectroscopy are powerful optical measurement techniques used to characterize thin films, coatings, semiconductor materials, and engineered surfaces. By analyzing how light is reflected from or transmitted through a sample, researchers and manufacturers can evaluate film thickness, optical properties, coating performance, and material characteristics without contacting or damaging the sample.
StellarNet thin film metrology systems combine high-performance spectrometers, optical accessories, and advanced analysis software to provide fast, non-destructive measurements for optical coating characterization, semiconductor process monitoring, photovoltaic materials, display technologies, and advanced materials research.
- Measure %Transmission, Optical Density (OD), Absorbance, and Reflectance of films, filters, coatings, fibers, lenses and just about any optical element
- Optical Metrology Systems include a mini spectrometer, light source, and a metrology accessory such as a reflectance probe or transmission fixture
- Systems available for 190-2500nm wavelength range
- Resolutions better than 1nm with high stability research grade optical performance and repeatability
- SpectraWiz Mobile App and new interface options via SMART-Control
Optical Metrology & Filter Measurements
The most commonly used instrument for the measurement of the optical performance of filters, films, and optical components is a spectrometer. Easily measure %Transmission, Optical Density (OD), Absorbance, and Reflectance of just about any optical element for purposes of R&D, quality control, production, or simply to better understand your system.
Using a StellarNet fiber optic spectrometer coupled to a reflectance probe and fiber optic light source, it is possible to measure film thickness by detecting the sinusoidal fringe pattern from the samples specular reflectance. Choose between various StellarNet spectrometers to suite your Thin Film and/or optical measurement requirement. StellarNet offers model spectrometers that range from 190-2300nm. Dual channel configurations, extended range detectors, or high resolution optics can be employed to suite your optical measurement.
A fiber optic sample probe is powered with a fiber optic light source – SL1 tungsten krypton bulb (see other options below). For measuring the color of solid samples, an integrating sphere, such as the IC2, is used in place of the fiber optic reflectance probe to improve measurement consistency. The IC2 also acts as a cosine receptor to improve irradiance measurements. A white reflectance standard, such as the RS50 also listed below, is required to generate a reference for subsequent measurement of solid samples. For more information on color applications, refer to Color Measurement Systems.
Filter Transmission Measurements (200-1700nm) using a SL5 UV-VIS Deuterium Halogen Light Source, Transmission Fixture, Optical Fibers and Y-splitter fiber, and BLACK-Comet + DWARF-Star DUAL-DSR System
Specular Reflectance Measurement 280-900nm using an SL1-Filter Tungsten Halogen Lamp, R600 Reflectance Probe, and a BLACK-Comet Spectrometer
Visible Filter Transmission Measurements (220-1100nm) using a SL1-Filter Halogen Light Source, Transmission Fixture, and F600 Optical Fibers
Reflectance and Transmission Sample Spectra
Transmission Measurements of Neutral Density Filters. With a StellarNet optical metrology system you will never have to guess again.
RED-Wave-NIR-InGaAs– silver film for reference surface
Lens, filters, films, coatings, and plastics sometimes will have interesting characteristic fringe patterns in the far NIR. Be sure to test your samples!
Transmission spectra of various sun glass brands for color and UV blocking optical properties
When Should I Use Reflectance vs Transmission?
| Application | Preferred Technique | Why? |
|---|---|---|
| Semiconductor Wafers | Reflectance | Opaque silicon substrates make reflectance ideal for oxide, nitride, and photoresist measurements. |
| Photoresists | Reflectance | Fast, non-contact measurement on silicon wafers during lithography and process control. |
| Optical Coatings | Reflectance & Transmission | Used together to characterize coating performance, thickness, and spectral response. |
| Optical Filters | Reflectance & Transmission | Verifies transmission bands, blocking performance, and multilayer optical designs. |
| Anti-Reflective (AR) Coatings | Reflectance | Measures low reflectance and coating thickness on optical components. |
| Solar Cells & Photovoltaics | Reflectance | Evaluates anti-reflective coatings, TCOs, and photovoltaic thin films. |
| Display Technologies (OLED, LCD & MicroLED) | Reflectance | Characterizes display coatings, ITO, OLED layers, and optical films. |
| Transparent Glass & Polymer Films | Transmission | Ideal for highly transparent substrates where transmitted light provides additional information. |
| Silicon Photonics & PICs | Reflectance | Characterizes waveguides, dielectric films, and multilayer photonic structures. |
| Laser Optics & Dielectric Mirrors | Reflectance | Measures high-reflectivity coatings, dielectric mirrors, and laser optical components. |
Reflectance and Transmission System Options and Pricing
Spectrometers for Optical Metrology Applications
BLACK-Comet
Concave Grating spectrometer for UV-VIS. C(190-850nm) or CXR (280-900nm) $3,950.00
BLACK-Comet-SR
Super Range Concave Grating spectrometer for UV-VIS-NIR. C-SR (200-1080nm) or CXR-SR (220-1100nm) $4,450.00
GREEN-Wave
Low cost spectrometer designed for teaching labs $2,350.00
DWARF-Star
Compact NIR spectrometer with miniature size (5″x2″x3″) and extremely robust design with 512 element PDA, range 900-1700nm, 2.5nm resolution with 25um slit, 16-bit digitizer, high speed USB-2. $15,500.00
DWARF-Star-1024
Compact fiber optic spectrometer with miniature size (5″x2″x3″) and extremely robust design with 1024 element InGaAs PDA, range 900-1700nm, 1.25nm resolution with 25um slit, 16-bit digitizer, high speed USB-2. $21,525.00
RED-WaveNIRX-512
Extended range NIR spectrometer for 900-2300nm with 512 element cooled PDA $26,250.00
RED-WaveNIRX-1024
Extended range NIR spectrometer for 900-2300nm with 1024 element cooled PDA $33,600.00
Light Sources and Fiber Optic Accessories for Optical Metrology
SL1 Miniature VIS-NIR light source with 10,000 hour Tungsten Krypton bulb for 300-2200nm Requires UP12V $710.00
SL3 15 Watt Deuterium light source with 4000 hour bulb, has integrated 0.5" diameter filter holder Requires UP24V $2,155.00
SL5 Miniature Deuterium+Halogen light source for UV-VIS, with independent lamp and shutter Requires UP12V $2,150.00
TXF-4 Vertical transmission fixture with variable path length, includes 2 collimating lenses. $580.00
F600-VISNIR Armored fiber optic cable, 600um core, 2 meter with black PVC jacket $210.00
RS50 Reflectance standard to set white reference, 50mm diameter $365.00
RFX-2 Reflectance fixture with integrated light source & F600-VIS-NIR fiber optic cable $575.00
RPH2 Reflectance Probe Holder block that maintains a 45 and/or 90 degree angle and user set distance from sample (0-3/4"). $210.00
RTIP45 45° angled tip for reflectance probes; includes locking screw for positioning $160.00
R600-8-UVVIS-SR Reflectance probe for UV and Visible; 7 around 1 with 600um fibers $785.00
R600-8-VISNIR Reflectance probe for Visible and NIR; 7 around 1 with 600um fibers $785.00
SpectraWiz Software
Free SpectraWiz Software
The powerful SpectraWiz® spectrometer software is provided free of charge with every spectrometer instrument. This includes drivers and customizable software for Windows. The SpectraWiz software is considered the “Swiss Army Knife of Spectroscopy” and may be used to accurately measure wavelength emissions, reflectance, transmission, absorption, concentrations, and absolute intensities. In addition to real-time spectroscopy, SpectraWiz® has built-in applications for SpectroRadiometry, SpectroColorimetry, ChemWiz chemistry lab concentration analyzer, and UV level monitors. Download SpectraWiz Software FREE
ChemWiz for iPhone and Andriod – Chemical Absorbance App
The ChemWiz App for all WiFi enabled StellarNet spectrometers makes real-time chemical absorbance measurement quick and easy. Acquire full spectrum analysis, create calibration methods, and record calculated concentration data! This intuitive app lets users control their spectrometer from their phone or tablet reducing lab bench clutter and improving overall lab experience. Save spectra, absorbance, and concentration data, export as .ABS text data file, screenshot, and/or PDF report with all parameters listed.
ile, screenshot, and/or PDF report with all parameters listed.
SpectraWiz MobileTM for Linux/RasPi
The SpectraWiz MobileTM for Linux/RasPi is designed to run directly on the SMART-Control spectrometer interfaces or can be packaged for your your requirements. Using the local access point or WiFi you can easily log in and run applications for General Spectroscopy, Radiometry, Colorimetry, and Concentration analysis.
The easy to use applications are written in python and provided free with purchase of a SMART-Control spectrometer upgrade. Source codes can be purchased separately and can be further customized to suite each user’s requirements. OEM customers can add their logos or additional computations and industrial customers can set their spectrometer and stream their data to PLCs or other process monitoring platforms. SMART-Control devices support RS232, 4-20mA Analog, 26 pin digital I/O, Ethernet, I2C and other options available upon request.
Interface Options
Standard Interface
The system includes a high speed plug & play interface using USB-2 connection.
zAP2 WiFi Upgrade
The zAP2 WiFi upgrade enables WiFi access to any spectrometer. Now use our new StellarRAD App on your iPhone or Android device. zAP2 WiFi upgrade can be added to all new and some old spectrometers in the field. Once added, the spectrometer runs as normal receiving power from the computer’s USB; if 5VDC power is connected directly to the BLUE-Wave, the zAP2 WiFi powers up and you can connect your device. Also, the zAP2 enables USB over IP and you can run SpectraWiz wirelessly on your Windows computer. $630.00
SMART-Control Interface Upgrade
The SMART-Control device offers communication flexibility and application specific customization for any StellarNet spectrometer. This add-on interface includes an integrated CPU with 1GB RAM and many communication protocols such as RS232, SPI, 4-20mA Analog for PLCs, Digital I/O, Ethernet, Wifi and many other options. The SMART-Control allows customers to move their spectrometers into process or OEM environments and stream their selected real world data. $2,100.00
Add Near Infrared to your Reflectance and Transmission System
StellarNet Dual-Detector Super Range (DSR) spectrometer systems combine two instru
ments to cover the ultra violet, visible and near infrared portions of the electromagnetic spectrum. The two instruments work as one creating a unified spectral graph over the entire wavelength region, 200-2300nm.
Sample Color and Composition
- Measure sample CIELAB color and quantitative composition simultaneously
- Fast, easy results with little to no sample prep using reflectance fixture.
Accessories for Reflectance and Transmission
Transmission Fixtures
TXF-4 includes two collimating lenses which allows the sample to be oriented vertically as shown above. The standard fixture allows a variable pathlength from 0 to 7cm. Custom posts can be designed to increase pathlength. Interchangeable parts allow the TXF-4 to be easily converted into the RPH-3 using the same base and stand.
TXF-IC2 Vertical transmission fixture with variable path length, includes 1 collimating lens and 1 miniature 2″ integrating sphere with 5/8″ port.
The integrating sphere collector is useful when measuring the transmission of thick samples such as bulletproof glass or samples with curved surfaces such as lenses.
Reflectance Accessories
The RPH Reflectance Probe has 6 illuminating fibers and 1 read fiber bundled together. As an option, the2R probe has 5 illuminating fibers and 2 read fibers. Fibers are offered in 400μm and 600μm diameters. The RS50 is a 50mm diameter white reflectance standard made of Halon. It is used to take reference measurements using the R400 Reflectance Probe. The white standard will reflect >97% of the light from 300-1700nm.
See more of StellarNet’s Reflectance probes and standards information!!!
StellarNet’s RFX-2 for Color Measurement Applications
Reflectance fixture has integrated light source to enable facile color measurement of solids and powders by placing sample on top.
Fiber Optic Cables
Ruggedized, multimode fiber optic cables are available with SMA-905 connectors, ¼ inch diameter. steel mono-coil armor with black PVC jacket. Sizes include 400, 600, or 1000μm core diameters
Optical Metrology Standards 
RS50 is a 50mm diameter white reflectance standard made of Halon. It is used to take reference measurements using the R400 Reflectance Probe. The white standard will reflect >97% of the light from 300-1700nm
RS-HR High-reflectivity Specular Reflectance Standard is a mirrored,fused-silica standard that can be used as a reference when 
measuring surfaces with high specular reflectance such as optical substrates, coatings, and metals
Technical Information Request
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