Tunable LED Uniform Light Sources: SpectralLED®

Don’t get bogged down with the complexity of other light sources.

Gamma Scientific’s line of SpectralLED Tunable Uniform Light Sources make previous light source technologies obsolete.

Offering easy spectral simulation capabilities, a high number of unique LED channels, and blindingly bright output power, nothing else on the market compares to the SpectralLED.

And just because it’s easy to use doesn’t mean you have to sacrifice performance or accuracy. Gamma Scientific’s proprietary spectral calibration techniques and powerful spectral fitting engine allow for unsurpassed precision and repeatability in the output spectrum, all seamlessly integrated into the unit firmware.

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Video webinar presentation of SpectralLED® Tunable Light Source

Brief video demonstration of RS-7 SpectralLED® Tunable Light Source using 35 discrete LED wavelengths covering the Visible and NIR range


  • Unprecedented Resolution and Accuracy – 32 Discrete LED Wavelengths Covering the Visible and NIR
  • Powerful Synthesis Engine – Quickly Simulate any CIE Illuminant or Macbeth™ / X-RITE™ Color Patch
  • Flexible Interface – Built-in RMS Spectral Fitting for Simulation of Any User Imported Spectra
  • Uniform 75mm Radiance Output Port or Optional Baffle Tube for Irradiance
  • Easily Adaptable – for Automated Test Systems and Production Line Integration
  • Pure DC Constant Current Drivers and Built-in Optical Feedback Photodiode System – Ensure Accurate Output in Real Time
  • On-board Thermal Electric Cooler and Feedback – for LED Temperature Control
  • ISO/IEC 17025 NVLAP Calibration Laboratory (Lab Code 200823-0) – Ensures Superior Wavelength and Color Accuracy


Unprecedented Resolution and Accuracy for Camera and Image Sensor Calibration

Light sources are only as accurate as the calibration. As a world leader in high performance spectroradiometers, and with an in-house ISO/IEC 17025 NVLAP Accredited Calibration Laboratory (Lab Code 200823-0), you can trust Gamma Scientific’s NIST-traceable calibration that comes programmed into every SpectralLED® source.

Replace multiple instruments with a single device. With a fully spectrally tunable output spectrum, all you need is one SpectralLED to generate any arbitrary spectral power distribution. Whether it be blackbody, daylight, fluorescent, LED, or something completely unique, the SpectralLED can give you an accurate match.

Replace monochromators with a solid stage design. By sweeping through individual LED channels, the SpectralLED can emulate a traditional monochromator light source. With no moving parts and no halogen input illumination, the solid state SpectralLED is the clear choice for demanding applications.

Unlimited possibilities for limitless spectra. With independent 16-bit control on 35 LED channels, there are virtually infinite possibilities for what the SpectralLED can do for you. Compared with other “next-gen” LED light sources, the SpectralLED offers more channels, brighter output, higher accuracy, and more powerful features for simulation. No external software is required, the SpectralLED firmware controls RMS fitting, calibration storage, and presets. Direct integrating into production lines or test systems is easy with universally compatible USB and RS-232 interfaces.

Gamma Scientific SpectralLED light sources feature a proprietary electrical design for superior accuracy and reliability. The completely redesigned drive electronics provide a pure DC constant current LED drive with floating differential sensing. This means there is no flicker and no uncertainty in the drive current. Couple that with built-in optical feedback, and the SpectralLED is able to accurately control optical output power to within a fraction of a percent. On-board thermal control maintains the LED substrate temperature to ensure spectrum is stable even at high drive currents.

Industry Applications

  • Camera and Image Sensor Calibration (CCD, CMOS, etc.)
  • Ambient Light Sensor Calibration
  • Detector Responsivity
  • OEM Camera Manufacturing
  • Spectrum/Illuminant Simulation
  • Diagnostic Medical Imaging
  • Technical and Industrial Photography


Measurement Applications

  • White Balance
  • Quantum Efficiency
  • Spatial Non-Uniformity
  • Pixel Defects
  • Cross Talk
  • Vignetting Correction
  • Sensitivity
  • Signal-to-Noise
  • Linearity
  • ISO Speed
  • Saturation Exposure
  • Dynamic Range



Spectral Range380nm – 1000nm (Standard Version, Custom Configurations Available)
Spectral Output32 Discrete LED Channels, 3 Broadband LED Channels
Visible Resolution ≈15nm, NIR Resolution ≈50nm (Typical Channel Spacing)
Spectral Peaks1395nm, 405nm, 420nm, 430nm, 450nm, 460nm, 475nm, 495nm,
505nm, 520nm, 525nm, 535nm, 570nm, 595nm, 610nm, 700nm,
620nm, 630nm, 637nm, 660nm, 675nm, 685nm, 715nm, 730nm,
750nm, 760nm, 780nm, 805nm, 850nm, 895nm, 940nm, 965nm,
2700K Warm White, 3000K Warm White, 6500K Cool White
(Standard Version, Custom Configurations Available)
Spectral BandwidthChannel Dependent
Visible Typical ≈20nm FWHM, NIR Typical ≈50nm FWHM
Source Geometry75mm Diameter Uniform Output, Lambertian Radiant Source
Spatial Uniformity2≥ 97%
Optical GeometryBuilt-in Integrating Sphere, 200mm Diameter
(Other Output Geometries Available for Projection or Illuminator Applications)
Radiance Range3Typical Maximum ≈ 15,000μW/cm²/sr  Typical Minimum ≈ 15μW/cm²/sr (Spectrum Dependent)
Luminance Range3Typical Maximum ≈ 30,000cd/m² Typical Minimum ≈ 30cd/m² (Spectrum Dependent)
CCT Range1,900K – 40,000K
Preset SpectraCIE Illuminants A, B, C, D50, D55, D65, D75, E, F1-F12,
Macbeth™/X-Rite™ Color Patches
Custom Preset SpectraArbitrary Spectra can be Configured as Presets Using API
Gamma can Provide Factory Loaded Custom Presets, Use Part Number RS-7-PRE
(Spectral Information must be Provided by Customer at Time of Order)
Illumination Stability≥ 99.99% after settling
(Channel Dependent, Settling Occurs After ≈50ms for Radiance and ≈2000ms for Color)
Illumination Accuracy± 1% Absolute NIST Traceable, Calibration Stored Internally
Spectral Accuracy± 1nm Centroid Wavelength
Color AccuracyCIE 1931 x,y = ±0.003
Linearity< 0.1% RMS of full scale
Temperature StabilityActive Thermoelectric Cooler with Feedback, Temperature Control within ± 1 C°
Long Term DriftOutput: ≤ 0.2%
Spectral: ≤ 1nm (Typical, Channel Dependent)
Electrical Resolution16 bit DAC for Channel Current Drivers
(64 Independent DACs, Certain LED Channels Require Multiple Current Drivers)
24 bit ADC for Internal Radiance Monitor/Feedback
Dynamic Range AdjustmentSpectrum Dependent, 4-5 Decades Typical
LED ControlPure DC Constant Current with Floating Differential Sensing
SoftwareFirmware Contains Full Spectral Calibration and Handles Spectral Fitting, Preset Storage, Real-time Optical Feedback, Radiometric and Photometric Units Supported.
InterfaceUSB 2.0 Type B Connector and DB-9 Connector
Interface ProtocolSimple ASCII Commands with Optional Binary Block Transfer
Supported Operating SystemsUSB Drivers for Windows, OSX, and Linux via FTDI virtual COM port
Legacy RS-232 Serial Port for Integration into Automated Systems (no OS required)
Input Voltage and Power110-240 VAC, 50-60Hz, 600W Maximum
System DimensionsHeight: 405mm (16in), Width: 460mm (18.1in), Depth: 305mm (12in), Weight: 17.5kg (38.6lbs)
RS-7-175mm Output with Radiance Calibration.
RS-7-21-meter Integrating Sphere with 300mm Uniform Output Port with Radiance Calibration.  Compatible with up to 4 sets of RS-7 Drive Electronics Running in Parallel to Deliver Increased Output Power.
RS-7-3Fiber Optic Output with Irradiance Calibration
RS-7-4Wafer Testing Configuration with Irradiance Calibration
RS-7-5150mm Baffle Tube Output with Irradiance Calibration
RS-7-1-IRISUPGIris Upgrade for the RS-7-1. Variable Output Aperture using built-in motorized iris. RS-7 Firmware includes iris stepper motor control. Additional API commands are provided for easy adjustment of iris diameter.
RS-7-WAVEMONMulti-channel photodiode system provides amplitude feedback and real-time wavelength measurements. This assembly is a discrete module and can be used with any RS-7 optical configuration.
1. LED output wavelength can vary slightly from unit to unit, actual peak wavelength is typically ±5nm from the specified peak.
2. Uniformity measured using an 8° FOV at the output plane of the device. Uniformity spec is measured over the entire Ø 75mm active area, when considering only the center Ø 50mm area uniformity exceeds 98%
3. Spectra fit over a wavelength range of 380-780nm, maximum output is dependent on spectral content of the target spectra. Most CIE illuminants and color patches can fit to at least this level, typically spectra can far exceed this maximum, however some spectra cannot achieve this maximum

Wavelength Monitor System:

The Wavelength Monitor System is a multi-channel photodiode system which provides amplitude feedback and real-time wavelength measurements. It consists of three photodiodes each with an independent transimpedance amplifier circuit. Proprietary optical filtering techniques allows for wavelength accuracy of +/-0.25nm and repeatability of +/-0.05nm using only 3 photodiode channels. The Wavelength Monitor PCBA, photodiodes, and optical filter assembly is temperature stabilized using a Peltier cooler and thermistor in a PID feedback loop. This assembly is a discrete module which can be used in on any RS-7 output configuration (e.g. sphere, baffle tube, fiber optic output).




Motorized Iris:

The motorized iris for the RS-7-1 is a Variable Output Port Aperture using a built-in, motorized iris. RS-7 Firmware includes iris stepper motor control, and additional API commands are provided for easy adjustment of the iris diameter.

SpectralLED® Illuminant A (Blackbody) Simulation using RMS Spectrum Fitting. Target (Blue) Output (Red)

SpectralLED® Illuminant D65 (Daylight 6500K) Simulation using RMS Spectrum Fitting. Target (Blue) Output (Red)

SpectralLED RS-7-1

Standard configuration with 75mm output port, built-in integrating sphere, 35 unique channels, and unlimited spectral possibilities.

SpectralLED RS-7-2

For applications requiring a larger uniform output, this model offers 1-meter integrating sphere with an ultra uniform 300mm output port.

SpectralLED RS-7-3

For applications with tight mechanical space constraints, a fiber optic version is available. This system is custom configured for each customer’s application.

SpectralLED RS-7-4

Illuminator solution for wafer level testing of CCD and CMOS sensors.  Turnkey drop-in addition to commercially available systems.

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RS -7 Channel Spectra


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