Available Photonics Experiments:

P5834 Diffraction Gratings PDF Download page

  • Principle of gratings
  • Diffraction order
  • Transmission grating
  • Measuring wavelength
  • Spectral lamp
  • Line spectrum
  • Spectral resolution
  • Examples of investigations and measurements

Measuring the laser wavelength

By means of the provided green laser (9) its wavelength is determined by using a grating with known grating constants. A set of 5 gratings with:
80 lines / mm
100 lines / mm
300 lines / mm
600 lines / mm
1200 lines / mm
is provided to demonstrate and measure the spatial intensity distribution. By using a crossed second grating in addition, an impressive two dimensional Intensity pattern will be observed

Spectral resolution

The intensity distribution can either be determined by the optical scale or the provided photodetector. For each grating and beam expander a different pattern will be generated. Already from the visual impression the resolution can be determined but however also be measured bay means of the provided photo detector and digital voltmeter. It should be noted that the µA range is recommended for a linear relation between the photocurrent and the light intensity.

Diffraction of a line spectrum

The spectral lamp contains a modern energy saving lamp with integrated 220 VAC power supply and emits a spectrum as shown on the right.
The spectral lamp is used in connection with the set of gratings to analyse the effect of the grating constant with respect to the resolution of a line spectrum.

Spectrum of the lamp provided by manufacturer

Spectrum taken with grating with 1200 lines/mm
  • P5834 Diffraction Grating consisting of:
12B-11341Optical screen with XY scale on block
24B-06101Achromat f=40 mm, C30 mount
34B-07201Beam expander magnification 6x
44B-07241Beam expander magnification 2.7x
54B-07501Set of 5 transmission gratings
6ED-00101Adaptive power supply APS-05
7ED-02101PIN Photodetector, BPX61 with connection leads
8LS-00901Spectral lamp with slit and power supply
9LS-01101DIMO diode laser module, 532 nm
10MC-02501Profile Rail MG-65, 300 mm
11TP-00301Digital multimeter 3 1/2 digits
12XM-02101Triple swivel unit
13XM-10901Mounting plate C25 with carrier 20 mm
14XM-11001Mounting plate, including carrier 20 mm , C30
15XM-11082Mounting plate C50 with carrier 20 mm
16XM-11101Adjustment holder, 4 axes, carrier 20 mm