Optical radition is part of the electromagnetic spectrum, covers from ultraviolet (UV), visible, to infrared (IR) light, with the wavelengths from 100 nm to 1mm. Optical radiation metrology is the science of measurement for light, including the measurement of optical radiation, characterization of light sources and optical detectors / sensors, measurement of optical properties of materials, and so on.


The Optical Radiation Metrology Lab successfully developed an optical phantom to simulate the optical property of human skin as well as the layer structures of the epidermis and dermis. The optical phantom can be used as reference for Optical Coherence Tomography (OCT) and Reflectance Confocal Microscopy (RCM) in cosmetics and dermatological diagnostics.

Measurement for additive manufacturing is a new focus of Optical Radiation Metrology Lab. We started a project on accurate in-situ monitoring and adaptive close loop feedback control for additive manufacturing process recently. In this project, we will develop the characterization method for the additive manufacturing materials, and the monitoring tools, eg. power meters and CCD cameras, in process monitoring.

Measurement Standards and Dissemination

The Optical Radiation Metrology Lab is responsible for the development, maintenance and dissemination of Singapore’s national measurement standards for radiometry, photometry, spectrophotometry and fiber optics to ensure all relevant measurements are traceable to SI units in Singapore. With these capabilities, the lab provides traceable calibration and measurement services to the industries. Beyond measurement traceability dissemination, it also aims to advance measurement technologies in optical radiation metrology. These measurement technologies open up opportunities for R&D and manufacturers in industry.

Optical Radiometry Standard

Traceable to our primary standard for optical radiometry - cryogenics radiometer, and primary standard for optical radiation source, we provide measurement services in radiometry for photodetector spectral responsivity scale characterization, solar cell efficiency measurement, fiber optics measurement, laser power meters, UV meters, and so on. For fiber optics, we do calibration or testing for OTDR, fiber optics source, fiber optics power meter, optical spectral analyser, wavemeter.

Services Provided:

  • Photodetector spectral responsivity calibration: 250 nm – 1640 nm
  • Calibration for reference solar cells: efficiency, I-V, short circuit current, under standard testing conditions
  • Calibration of laser power meters and laser measurement: 400 nm – 900 nm
  • Calibration of UV meters: 254 nm, 312 nm, 334 nm, 365 nm, 405 nm, 436 nm
  • Calibration of Fibre Optic equipment, and measurement of fiber optic devices
  • Fiber optics power at 850 nm, 1300 nm, 1310 nm, and 1550 nm
  • Optical spectrum analyser calibration at 1310 nm and 1550 nm
  • Fiber distance, optical attenuation and return loss of OTDR at 1310 nm and 1550 nm

Photometry Standard

We provide measurement services in photometry for color, spectral transmittance/reflectance, illuminance meters, lamps and LEDs. For lamps and LEDs, we do measurement for luminous flux, luminous intensity, spectrum, spectral irradiance and so on.

Services Provided:

  • Calibration of lamps and lux meters:
  • Tungsten lamps, LEDs, illuminance meters, luminance meters, spectral irradiance, colour rendering index, color temperature, colorimeters…

  • Measurement of optical properties of material:
  • Spectral transmittance and reflectance


training courses

We provides trainings for technical professionals and managers on optical measurement. These trainings aim to introduce metrological concepts and practical knowledge in the optical measurement.

Courses conducted in the past:

  • Accurate Measurement of Laser/Light Sources and Calibration of photodetectors
  • Light and Colour Measurements
  • Fiber Optics and Measurement Techniques
  • UV measurement

International Comparisons

To ensure the international equivalence of CMCs, the Optical Radiation Laboratory participated in many international comparisons in both the photometry and radiometry domains. NMC is currently the member in the Consultative Committee for Photometry and Radiometry (CCPR) and also the member in the Asia Pacific Metrology Programme (APMP) Technical Committee for Photometry and Radiometry (TCPR).

Recently participated international comparisons:

  • APMP.PR-K3 Luminous intensity
  • APMP.PR-K4 Luminous flux
  • APMP PR-S3 APMP Supplementary Comparisons of LED Measurements
  • CCPR-K2.a.2016 Key Comparison on Spectral Responsivity 900 nm – 1600 nm
  • CCPR-K2.b.2016 Key Comparison on Spectral responsivity 300 nm - 1000 nm
  • APMP.PR-S8 Supplementary Comparison on Optical Fiber Length
  • CCPR-K6 Key Comparison on Spectral Regular Transmittance
  • CCPR-K1.a Key Comparison on Spectral Irradiance 250 nm - 2500 nm
  • EURAMET.PR-S5 Reference Solar Cells at Standard Test Conditions

Research Projects

research project

In-situ Melt Pool Temperature Monitoring and Close-loop Control for LAAM. In metal additive manufacturing, melting pool thermal behavior determines the quality of the process and processed parts. Accurate temperature distribution measurement is a key for ensuring consistent process. This project aims to develop method for melting pool temperature distribution measurement in laser assisted additive manufacture (LAAM). By studying the correlation between key parameter of the distribution and processed part quality, a close loop control system will be developed for consistent AM process.


interesting stories

Color and human eyes

Optical radiometry is described and measured in purely physical terms, using physical quantities and units that have general application throughout the physical sciences. Photometry is about visible optical radiation, described and measured in such a way that the results correlate as closely as possible with what the relevant visual sensation would be of a normal human observer. Hence color is a term studied in photometry.