Electro-optic effect of crystal (Pockels effect)
Experiment contents and related  subjects:
Observe the interference patterns formed by convergent polarized light through the LiNbO3 crystals and compare the difference among different voltage conditions to understand the difference between uniaxial and biaxial crystals.
Observe he different polarization states of output light under different oltages ,understand the Pockels effect mechanism.
Measure the half-wave voltage and determine the linear relationship betweenΔn and E to plot the modulation curves of laser.
Using a sinusoidal electric signal to modulate the crystal so as to achieve the optical transmission of electric signals, understand the influence to the modulation ,transmission process caused by working points.
To achieve the optical transmission of audio signals through extemal audio signal ,understand the principles and methods of extemal modulation in optical communication signal.
Features of the instruments:
Using semiconductor laser as the light source (650nm, 4mW).
The limiting aperture area of crystal is 5 × 5mm2.
The maximum voltage Vmax is ≥ 1600V which makes the phenomenon more clear and complete.
The process that the LN crystal changes from a uniaxial crystal to biaxial crystal under the electric field can be observed, the interference pattern is complete and clear.
Complete set of equipment:
Optical experiment guide, semiconductor laser, beam expander mirror . polarizer, analyzer, 1/4 wave plate, LN crystal accessories (including three-dimensional adjustment frame), laser power indicator, oscilloscope (self-contained), the audio signal source (self-contained )and etc..