Source Measurement The most common measurements of sources

Source Measurement The most common measurements of sources include: Ø Radiance - Light emitted in a particular direction Ø Irradiance – Light falling onto a surface Ø Total flux – Total light emitted in all directions Optronic Laboratories, Inc.

Radiance Measurement Source Solid Collection angle Measurement area Ø Radiance is normally measured with a telescope Ø The solid collection angle corresponds to the size of the lens Ø The measurement area corresponds to the field-of-view of the telescope Optronic Laboratories, Inc.

Radiance Measurement Source Solid Collection angle Measurement area Ø The term “radiance” in this section also refers to related units such as luminance and radiant intensity Ø Radiant intensity applies to small or distant objects that are smaller than the telescope field-of-view Optronic Laboratories, Inc.

Radiance Measurement Ø Optronic Laboratories, Inc. manufactures a large range of telescope, microscope and imaging optic modules for radiance measurements Ø To illustrate a typical system for radiance measurement, we will use the OL Series 730 -9 Telescopes Optronic Laboratories, Inc.

The OL Series 730 -9 Telescopes Ø For luminance and radiance of sources from 200 nm to 14, 000 nm Reflex viewing Adjustable focus Wide range of lenses Optronic Laboratories, Inc.

The OL Series 730 -9 Telescopes Ø For luminance and radiance of sources from 200 nm to 14, 000 nm Here is how it works Light coming from the source… Optronic Laboratories, Inc.

The OL Series 730 -9 Telescopes Ø For luminance and radiance of sources from 200 nm to 14, 000 nm The sectional reflex mirror drawing lets the shows userwhat see happens whatinside is being themeasured solid housing If the mirror is flipped out of the way …is picked up at some distance and focussed by the OL 730 -9 Optronic Laboratories, Inc.

The OL Series 730 -9 Telescopes Ø For luminance and radiance of sources from 200 nm to 14, 000 nm The image is sent via the field-of-view aperture to the spectroradiometer Optronic Laboratories, Inc.

Radiance Measurement Putting together an OL 750 radiance system We start with an OL 750 monochromator And a detector Positive location & easy assembly Then we add the OL 730 -9 Optronic Laboratories, Inc.

Radiance Measurement We have a complete radiance measurement system Optronic Laboratories, Inc.

Irradiance and Total Flux Measurement Ø To measure irradiance (or illuminance), a cosine response integrating sphere such as the OL IS 670 is substituted for the OL 730 -9 Ø To measure total flux, a large sphere (typically 18 to 76 inches) is substituted for the OL 730 -9 Optronic Laboratories, Inc.

Irradiance Measurement A complete irradiance measurement system OL IS-670 nearperfect cosine response integrating sphere Optronic Laboratories, Inc.