Acousto-optic polychromatic light modulator

An acousto-optic polychromatic light modulating apparatus comprising:

• an acousto-optic medium having a first face from which an acoustic wave is to be launched into said medium for interaction with a polychromatic input light beam, a second face upon which multiple color components of said polychromatic input light beam are collinearly incident, and a third face from which a light beam travelling through said acousto-optic medium is diffracted;
• a piezoelectric transducer mounted on the first face of said acousto-optic medium and to which a multi-frequency RF input signal is applied, said piezoelectric transducer being operative to launch a multi-frequency acoustic wave into said acousto-optic medium for interaction with said polychromatic input light beam as it travels through said acousto-optic medium;
• and
• a multi-frequency RF signal driver which is operative to generate a plurality of RF signals for selective application to said piezoelectric transducer in order to control the launching of acoustic waves by said transducer, such that a respective one of an RF signal that has been selected from among the plurality of RF signals generated by said RF signal driver for application to said piezoelectric transducer effectively interacts with only a respective one wavelength component of said polychromatic light beam, said respective one wavelength being different from another wavelength component of said polychromatic light beam, thereby modulating the wavelength composition of said polychromatic light beam and producing a color composition-modulated polychromatic output light beam the respective color components of which are collinearly diffracted from said third face of said acousto-optic medium.

A method of modulating a polychromatic light beam comprising the steps of:

• (a) directing said polychromatic light beam having multiple color components which are collinearly incident upon a first face of an acousto-optic medium, said acousto-optic medium having a second face from which an acoustic wave is to be launched into said medium for interaction with said polychromatic light beam as it travels through said acousto-optic medium, and a third face from which a modulated polychromatic output light beam is diffracted;
• (b) generating a plurality of RF signals;
• and
• (c) launching a multi-frequency acoustic wave from said second face into said acousto-optic medium for interaction with said polychromatic light beam as it travels through said acousto-optic medium in accordance with the plurality of RF signals generated in step (b), such that each RF signal among the plurality of RF signals generated in step (b) effectively interacts with a respectively different wavelength component of said polychromatic light beam, thereby modulating respectively different wavelength components of said polychromatic light beam to produce a color composition-modulated polychromatic output light beam the respective color components of which are collinearly diffracted from said third face of said acousto-optic medium.

A polarization independent acousto-optic polychromatic light modulating apparatus comprising at least one birefringent plate, an acousto-optic medium having an entrance face and an exit face, said birefringent plate being placed in the vicinity of either the entrance face, the exit face or both the entrance and exit faces of said acousto-optic medium, a piezoelectric transducer attached to said acousto-optic medium and operative to convert electrical signals supplied thereto into ultrasonic waves, said ultrasonic waves being launched from said piezoelectric transducer into said acousto-optic medium for interaction with a substantially collinear randomly polarized polychromatic light beam incident upon and traveling through said birefringent plate and said acousto-optic medium, an electronic driver which is coupled to said piezoelectric transducer and which generates signals containing a plurality of RF frequencies at respectively controllable amplitudes, thereby selecting a desired combination of wavelengths as well as polarization states in no more than two individually substantially collinear polychromatic output beams diffracted from said acousto-optic interaction medium, and wherein said acousto-optic medium, its mode and acousto-optic interaction length thereof are such that there is effective interaction by a respective one of said plurality of RF frequencies with only a predetermined wavelength contained in said polychromatic output beam.