The Model 211 Photometric sensors are our standard base unit, designed with spectral responsivity that matches the human visual response. The products incorporate a silicon detector combined with a spectrally matched photometric filter.  An integrated cosine filter significantly reduces directional sensitivity for ease of use.

Our wide range of optical power meters, photometric and radiometric sensors is complemented by ISO/IEC 17025 accreditation by NVLAP (NVLAP lab code 200823-0), resulting in unmatched performance and custom configuration as required.

  • Luminous Flux Measurements (lm)
  • Illuminance Measurements (lux)
  • Luminous Intensity Measurements (cd)
  • Removable Cosine Receptor

 Key Specifications                          Part No. U23-01-101

CIE V (λ) Function

 f1’  ≤ 3%(standard

 f1′  ≤ 1.5% (special order)

Detector Information

Silicon      1.0 cm2 active area

Rise Time

3 µ sec

Dynamic Range(1)

1 x 10-2 to 5 x 105 lux

Typical Response(1)

3.2 x 10-9 A/lux


ISO17025, NIST Traceable


2 meter, included

Compatible with the UDT Handheld and Benchtop series Optical Meters and Integrating Spheres.

(1) Stand alone with cosine receptor. Value may differ when used with integrating sphere, or with cosine receptor removed.


UDT Model 211 Photometric Sensor