| 摘要 |
PURPOSE:To improve a modulation frequency and modulation speed by using the ac-Stark effect of the supersonic speed appearing when a laser beam is projected on and executing the polarization and modulation of incident laser light. CONSTITUTION:A level shift is generated by the ac-Stark effect in the peak of a very high frequency pulse train 7 having a plane wave shape when said pulse train 7 is projected on a medium 1. Then, the periodic change in absorptivity and change in refractive index of a pulse interval lambdam are generated in the medium. An incident beam 5 senses only the periodic change in the modulation frequency in the medium and, therefore, the diffraction of the incident beam is the same as in an ultrasonic wave deflector if the angular frequency omega of the incident beam is also detuned from the resonance in the same manner as for the angular frequency of driving light. This modulation frequency is larger by 3-4 digits than the modulation frequency of an ultrasonic modulator. Since the modulation speed is determined by the time required for the driving pulse light to cross the incident beam, the modulation at the speed higher by 4-5 digits than the ultrasonic modulator is possible if the diameter of the incident beam is assumed to be constant.
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