Introduction to radiometry

Radiometry is the measurement of radiation in the electromagnetic spectrum. This includes ultraviolet (UV), visible and infrared (IR) light.

Electromagnetic radiation is characterized by its frequency of oscillation. The frequency determines the "color" of the radiation (see Figure 1). The speed of light is a constant, and frequency is related to wavelength by the relationship:

C = lg
C = speed of light
l = wavelength
g = frequency

The preferred units of measure for wavelength are nanometers (nm) and micrometers (µm, or "microns").

The visible region of the electromagnetic spectrum can be divided into the basic colors of the rainbow: red, orange, yellow, green, blue, indigo and violet. Red light has the longest wavelength in the visible region (770 nm). Violet has the shortest (380nm).

Ultraviolet light is shorter in wavelength than visible light. It extends from 10 nm to 380 nm. And like the colors of the visible region, UV can be subdivided into smaller regions. The UVA region ranges from 380 nm down to 340 nm and is the least harmful of UV radiation. The vacuum-ultraviolet (VUV) and UVC regions are shorter and are important to the study of cancer.

Infrared light extends from 770 nm to 100 microns. Its regions are known as near-IR, mid-IR and far-IR.

Measurements of optical radiation require specific methods to obtain accurate measurements. UDT supplies calibrated detector/filter combinations that cover from 200-1800 nm (0.2 to 1.8 mm). To obtain accurate measurements, one must understand the light source (i.e. laser, lamp, LED); the optical medium (i.e. air, water, optics); and the particular response characteristics of the detector.

Radiometers

Model S350 Optometer
Model S370 Single-Channel Optometer
Model S380 Dual-Channel Optometer
Model S471 Portable Optometer (New Handheld Optometer)

Radiometric Sensor Heads

Amplifiers

TRAMP Amplifier

Laser Power Attenuators

Model 2575 Integrating Sphere
Model 2500 Integrating Sphere
Model 2525 Integrating Sphere
Model 2550 Attenuators

Housing, Stands And Adapters

Model 101-1 Universal Sensor Housing
Model 102 Filter Holder
Model 103 Standard Lab Stand
Model 104 Filter Holder And Coupler
Model 104-Mini Filter Holder And Coupler
Model 108 Male Coupler
Model 108-Mini Male Coupler
Model 109 Heavy-Duty Lab Stand
Model 1718 Set-up Adapter