Open resonator of a Nd:YAG laser

• Measure a characteristic of the pumping laser

Principle of a semi-conductor laser
Optical power/ current characteristic

• Configuration of a resonator

left resonator mirror: YAG crystal
right resonator mirror – semi-transparent  

• Concave mirror
• Absorption measurement of the YAG crystal to optimise the pumping laser
• Measurement of the lifetime of the laser level
• Passive and active Q-Switch to generate micropulses

Far field measurement of light sources e.g. LEDs, laser diodes, VCSELs

• Investigation of the radiation characteristic of optical sources
• Measurement of radiant intensity in W/sr

   of irradiance in W/m?
   and of optical power in W

• Complete half-space measurement with 2 DC motors
• Astigmatic radiation of a semi-conductor laser because of diffraction

Monochromator

Spectral measurement of light sources, e.g. LEDs, laser diodes, VCSELs and optical fibres

• Measurement of a spectrum of an LED, laser diode or halogen lamp
• Spectral attenuation measurement of an optical fibre
• Measurement of the colour of a plate using the spectral method

Polarisation modulation

of a HeNe laser with the aid of a Faraday rotator

• The magnetic field of a coil modulates the polarisation plane of a laser beam
• The beam is amplitude modulated by projecting the E-vector onto a fixed polarisation plane of a polarisation filter
• An audio frequency modulated to the beam is played back after the filter via a receiver on a loudspeaker