Experiment Of Light-operated Switch And Optical Phase Shifting

The interaction between the light and the atom is described in this thesis. The equations of motion of the density matrixes elements are deduced by using of the Schrodinger equation in the light and two level atom system. Utilizing the equations of motion, number calculation of the three level energy A type Electromagnetically Induced Transparent model has been done, obtaining the detuning relation between the probe beam and the pump beam, drawing the graph. Meanwhile, we introduced the equipments and the instrument tested and the fabrication which is needed for launching the optical switch experiment. We use the acoustic optical modulator in the optics on-off, for the extinction ratio of the acoustic optical modulator is greater than1000:1in general. The frequency and the phase of the radio-frequency signal will be brought in when modulating the light, because of such, we use the acoustic optical modulator realizing the optical phase shifting. One beam is acted as the reference beam, and the other beam phase can be appended arbitrarily just follow our demand, subsequently coincided with the probe beam, forming the steady Interference Fringes. The position between the light and dark streamers can be changed via the phase introduced by second beam, and this is verified the optical phase is introduced by the second beam definitely, and we can draw a conclusion:the amplified of phase introduced is twice of the radio-frequency signal’s. The reason is that radio-frequency signal addition to the acoustic optical modulator transformed to the ultrasonic wave is stationary field。Additionally, the diode laser need to frequency stabilization for light-operated switch experiments, it is required the detector, in order to detect the saturated absorption spectroscopy. It is usually weak for the saturated absorption spectroscopy signal, and will be easily embedded in noise. It is the key to solve this issue in the following experiments, the owning higher signal-to-noise performance subtracter is also introduced in this thesis, the intensity of the saturated absorption spectroscopy signal is amplified in the same time, and the fabrication of the subtracter is also successful, obtaining the clear saturated absorption spectroscopy signals graphs.Finally, according to the characteristics of the EIT and EIG designed the scheme of the light-operated switch experiments, and observed the on-off phenomenon via debugging the switch in the experiment. However, it hasn’t been perfect till now, there are many aspects can be improved for the switch, some explains have been provided in the thesis summaries.