Available Photonics Experiments:

P5822 Refraction of light PDF Download page

  • Rainbows
  • Refraction of light
  • Total reflection
  • Snell - Descartes law
  • Guiding of light
  • Optical fibre
OX-02
  • Examples of investigations and measurements
OXP-02.01 Snell’s law
A half-round transparent disc is used to verify Snell’s law of refraction and total reflection. The advantage of the disc lies in the fact that the leaving beam passes the curved surface always under 90° avoiding additional refraction. The disc is mounted on a turn table which can be rotated perpendicularly with respect to the optical axis of the collimated laser beam (3). On the rotatable arm of the swivel unit (6) a crossed hair target (2) is mounted into its holder (1) serving as goniometer to measure the angle of refraction. This experimental set-up allows measuring the deflection of the beam in relation to the angle of incidence verifying Snell’s law for the transition of light from air to a dense medium and vice versa.
OX-02.02 Refraction on plates
When a beam passes a transparent plate the it shows a particular kind of deflection, it is parallel shifted in relation to the incident beam. This parallel offset depends on the thickness and angle of incidence of the beam. The plate is mounted on a turn table as part of the swivel unit (6). The rotatable arm is turned into the zero position without the plate. By turning the table different angles of incident can be set and the deviation observed by the crossed hair target(2).
OX-02.3 Total reflection inside a slab
A laser beam entering declined a transparent slab or thin plate is propagating in a zigzag course due to multiple reflections throughout its way inside the slab. This effect is exploited in a variety of laser systems also termed as slab laser. In this way the length of the beam path inside the amplifying media is enhanced resulting in higher output of the system. The zigzag beam path can be observed in side the slab and by tilting the slab the numbers of reflection can be changed impressively.
OX-02.04 Optical fibres
The light propagation in optical fibres is based on the same principle as for the total reflection in slabs. As “light pipe” or optical fibre a piece of plastic optical fibre (7) is used. It demonstrates how light is confined in a narrow tunnel by total internal reflection. The optical fibre is mounted to a holder in such a way that the green beam of the DPSS laser (DPSS = diode pumped solid state) enters the fibre. If necessary the beam can be aligned by adjusting the fine pitch screws of the adjustment holder (4) in XY direction as well as its azimuth and elevation angle.
OX-02.05 Rainbow
“The rainbow has a place in legend owing to its beauty and the historical difficulty in explaining the phenomenon.” The mystery of the rainbow is lifted by using a transparent cylinder as two dimensional model of a raindrop. A laser beam acts in the same way as the sun rays which are affected by the raindrops to generate a rainbow. The process of refraction and total reflection is demonstrated and explained in an impressive way. The “rain drop model” is asymmetrically mounted onto a turn table and allows the simulation of different angle of incidence of the laser beam
  • P5822 Refraction of light consisting of:
Item Code Qty Description
1 2B-0224 1 Mounting plate 40, C25
2 2B-1130 1 Crossed hair target
3 4S-0226 1 Dimo diode laser module, 532 nm (green), YAG
4 ED-0010 1 Adaptive power supply APS-05
5 MC-0250 1 Profile Rail MG-65, 300 mm
6 XM-0210 1 Triple swivel unit
7 XM-0330 1 Optical fibre model
8 XM-1040 1 Collection of mounted models
9 XM-1110 1 Adjustment holder, 4 axes, carrier 20 mm