Available Photonics Experiments:

P5821 Absorption and Emission PDF Download page


  • Absorption
  • Beer - Lambert law
  • Fluorescent plates
  • Stimulated Emission
  • Phosphorescence
  • LED - Emission
  • Examples of investigations and measurements
Lambert Beer Law
The Lambert-Beer law relates the absorption of the light to the properties of the material where the light is propagating. Within a first experiment the influence of the absorbing material on the intensity of transmitted light is investigated. The absorbing probe is made from PMMA also known as acrylic glass or Plexiglas (17). It is positioned on top of the carrier in such a way that three different lengths are used to measure the resulting intensity. In the same way the LED can be changed to observe the relation to different wavelength.
Absorption spectrum
With the white light LED (9) and the provided optical grating (6) the spectral distribution of the absorption spectrum of the fluorescent filter (5) can be observed on the optical screen. The absorption spectrum is imaged by means of the lenses (3) to the optical screen (13). The emission of the LED is collimated by the lens (2) and passes the fluorescent filter. The white LED mainly consists of red, green and blue lines and serves as spectral lamp in this concept.
  Fluorescence spectrum
Within the same set-up as before the excitation of the provided fluorescing samples (5) with LED’s of different wavelengths are performed. By means of the grating and the lenses the spectra of the LED is imaged to the optical screen. When inserting the fluorescent plates (5) additional lines will appear and others vanish.
Phosphorescence
The phosphorescing sample (4) is irradiated with different wavelength provided by the LED (9,10,11). The wavelength dependant sensitivity is measured by the provided photodetector (8) and the multimeter (15). Once the sample is irradiated for a certain time it is turned in its holder facing the photodetector.
In the same way the phosphorescence decay is measured as a function of time. The provided sample has a decay time of a couple of minutes so that the measurement can easily be taken by the multimeter reading.
  • P5821 Absorption and Emission consisting of:
Item Code Qty Description
1 3L-0390 1 BNC-Banana adapter connection leads 2x4 mm plugs
2 4B-0040 1 Plano-convex lens f=40 mm, diameter 25.4 mm, mounted in click 30 mm
3 4B-0060 2 Plano-convex lens f=60 mm, diameter 25.4 mm, click 30
4 4B-0130 1 Phosphorescing sample, click 25
5 4B-0670 1 Set of 3 fluorescent filters
6 4K-T600 1 T - grating 600 l/mm
7 ED-0010 1 Adaptive power supply APS-05
8 ED-0200 1 Photodetector Si PIN
9 LS-0010 1 LED white
10 LS-0020 1 LED red
11 LS-0050 1 LED blue
12 MC-0100 1 Screen holder on carrier 20
13 MC-0112 1 Optical screen 80 mm x 40 mm with horizontal and vertical scale
14 MC-0260 1 Profile Rail MG 65, 500 mm
15 TP-0030 1 Digital multimeter 3 1/2 digits
16 XM-0190 2 Plate holder on carrier 20
17 XM-0610 1 Absorption unit
18 XM-1090 1 Mounting Plate, including carrier 20 mm, C 25
19 XM-1100 3 Mounting plate, including carrier 20 mm , C30
20 XM-1110 1 Adjustment holder, 4 axes, carrier 20 mm