Multi-color acoustooptic modulator

Abstract

An apparatus and method are disclosed for acoustooptically modulating and diffracting a plurality of optical wavelengths contained in laser light impinging on an acoustooptic cell to form a composite output beam comprising intensity modulated component beams of selected wavelengths present in the impinging laser light. To accomplish this, a plurality of amplitude modulated electrical signals of different fixed frequencies are applied to an electrical-to-acoustical transducer operatively attached to the cell. Every frequency applied to the transducer produces an acoustic wave within the cell to form a diffraction spectrum of the wavelengths present in the laser light impinging or incident on the cell. The acoustic wave producing electrical frequencies are chosen such that diffracted component beams of selected wavelengths are collinear. Thus, the collinear component beams form a composite output beam comprising the selected diffracted wavelengths. Non-collinear beams of the selected wavelengths as well as unwanted diffracted wavelengths and undiffracted beams are masked or blocked from further passage through the optical system. The amplitudes of the electrical signals producing the acoustic waves within the cell are modulated independently to control the intensities of the individual component beams of selected wavelengths present in the composite output beam. The laser light impinging on the cell can comprise a single multi-wavelength beam; two collinear beams of different wavelengths and a third noncollinear beam of another wavelength; or beams of different wavelengths can be mutually noncollinear, the angles of impingement being chosen in accordance with what electrical frequencies are applied to the transducer.

I claim: 
     
       1. An apparatus .[.including an acoustooptic cell.]. for .[.modulating and.]. diffracting .Iadd.source .Iaddend.light of different wavelengths .[.impinging on said cell.]. into a composite, collinear output beam of light comprising a selected number of the different wavelengths present in said .[.impinging.]. .Iadd.source .Iaddend.light, the .[.combination.]. .Iadd.apparatus .Iaddend.comprising: an acoustooptic cell .[.having.]. .Iadd.locatable in the path of such source light; .Iaddend.   electrical-to-acoustical transducer means operatively attached .[.thereto.]. .Iadd.to said cell.Iaddend. ;   .[.means for impinging multi-wavelength light upon said cell;.].   means for generating a .[.plurality.]. .Iadd.number .Iaddend.of electrical signals .[.in accordance with a.]..Iadd.corresponding to the .Iaddend.selected number of .Iadd.wavelengths in the .Iaddend.collinear output .[.beams.]. .Iadd.beam.Iaddend. , each signal being of a .Iadd.predetermined .Iaddend.different fixed frequency .Iadd.selected to cause diffraction of at least a portion of light of each of the selected wavelengths along a common output axis; .Iaddend.and   means for applying said electrical signals to said transducer means to form acoustic waves in said cell which diffract said .Iadd.source .Iaddend.light .[.impinging on said cell.]. to form said composite, collinear output beam of light of said selected number of different wavelengths.   
     
     
       2. The invention of claim 1 .[.including means for modulating.]. .Iadd.wherein: said selected number of the different wavelengths are fixed wavelengths of λ 1 , λ 2 , λ ..., λ n  ; .Iaddend.   said .Iadd.plurality .Iaddend.of electrical signals .Iadd.are .Iaddend.of different fixed .[.frequency.]. .Iadd.frequencies ƒ 1 , ƒ 2 , ƒ ..., ƒ n  selected such that ƒ 1  λ 1  = ƒ 2  λ 2  = ƒ n  λ n . .Iaddend.   
     
     
       3. The invention of claim 1 .Iadd.including means for modulating said electrical signals .Iaddend.wherein said modulating means comprises means for independently controlling the amplitudes of said signals of different fixed frequencies. 
     
     
       4. The invention of claim 1 wherein said .[.impinging means.]. .Iadd.source light .Iaddend.comprises a multi-wavelength laser light beam. 
     
     
       5. The invention of claim 1 wherein.Iadd.: .Iaddend. said .[.impinging means.]. .Iadd.source light .Iaddend.comprises at least two collinear laser light beams of different wavelengths and at least one other laser light beam of another wavelength.Iadd., said collinear beams impinging upon said cell at one incident angle and said other beam impinging upon said cell at another incident angle; and   said fixed frequencies are chosen in accordance with said incident angles to form said composite, collinear output beam. .Iaddend.   
     
     
       6. An apparatus for recording a color image corresponding to a color image on a storage medium onto color sensitive photographic recording material, said apparatus comprising: means for scanning said medium with multi-wavelength light that is modulated in accordance with the color image on said medium;   photoelectric means for receiving the modulated light and for generating a number of electrical signals, each of which is representative of a different selected wavelength within the modulated light;   means responsive to said photoelectric means for modulating said electrical signals;   an acoustooptic cell having electrical-to-acoustical transducer means operatively attached thereto;   means for impinging multi-wavelength laser light upon said cell;   means for applying said modulated signals to said transducer means to produce acoustic waves in said cell which diffract said laser light into at least one composite, collinear output beam of said different selected wavelengths; and   means for scanning said photographic recording material with said composite, collinear output beam of light to record a color image thereon corresponding to the color image on said medium.   
     
     
       7. The invention of claim 6 further comprising means for synchronizing said photographic recording material scanning means with said medium scanning means. 
     
     
       8. An apparatus for recording a color image corresponding to a color image on a positive transparency onto color sensitive photographic recording material, said apparatus comprising: means for scanning said transparency with multi-wavelength light that is modulated in accordance with the color image on said transparency;   photoelectric means for receiving said modulated light and for generating a number of electrical signals of different fixed frequencies, the signals corresponding in number to a selected number of different wavelengths of modulated light;   means responsive to said photoelectric means for modulating said electrical signals;   an acoustooptic cell having electrical-to-acoustical transducer means operatively attached thereto;   means for impinging multi-wavelength laser light upon said cell;   means for applying said modulated electrical signals to said transducer means to produce acoustic waves in said cell which diffract said laser light to form at least one composite, collinear output beam of said different selected wavelengths; and   means for scanning said photographic recording material with said composite, collinear output beam to record a color image thereon corresponding to the color image on said transparency.   
     
     
       9. The invention of claim 8 further comprising means for synchronizing said photographic recording material scanning means with said transparency scanning means. 
     
     
       10. An apparatus for recording a color image corresponding to the positive of a negative image on a color transparency onto color sensitive photographic material, said apparatus comprising: means for scanning said negative transparency with a multi-wavelength beam of light to modulate the wavelengths thereof in accordance with the image on said negative transparency;   photoelectric means for receiving said modulated beam of light for generating electrical signals of different fixed frequencies in accordance with a number of different selected wavelengths in the modulated beam;   means responsive to said photoelectric means for amplitude modulating said electrical signals;   an acoustooptic cell having electrical-to-acoustical transducer means attached thereto;   means for impinging multi-wavelength laser light upon said cell;   means for applying said modulated electrical signals to said transducer means to produce acoustic waves in said cell which diffract said laser light to form at least one composite, collinear output beam of said different selected wavelengths; and   means for scanning said photographic recording material with said composite, collinear output beam to record a color image thereon corresponding to the positive of the negative image on the transparency.   
     
     
       11. An apparatus for recording a color image corresponding to a color image on an opaque support onto color sensitive photographic recording material, said apparatus comprising: means for scanning the color image on said support with a multi-wavelength beam of light the light of different wavelengths being reflected by and modulated in accordance with the color image;   photoelectric means for receiving the modulated wavelengths of light for generating electrical signals of different fixed frequencies in accordance with a number of different selected wavelengths present in the reflected light;   means responsive to said photoelectric means for modulating said electrical signals;   an acoustooptic cell having electrical-to-acoustical transducer means operatively attached thereto;   means for impinging multi-color laser light upon said cell;   means for applying said modulated electrical signals to said transducer means to produce acoustic waves in said cell which diffract said laser light to form at least one composite, collinear beam of said different selected wavelengths; and   means for scanning said photographic recording material with said composite, collinear output beam to record a color image thereon corresponding to the color image on said support.   
     
     
       12. An apparatus for recording an image on a color sensitive photographic recording material from color information in a storage medium, said apparatus comprising: means for directing a multi-wavelength beam of light onto said storage medium to produce a first X-Y scanning beam;   means for receiving the wavelengths of light as modulated by the color information and for converting a number of different selected modulated wavelengths of said light into electrical signals, each of which is modulated by a signal of different fixed frequency;   means responsive to said multi-wavelength beam of light and to said electrical signals for producing a second X-Y scanning beam comprising a group of different selected wavelengths of light corresponding in number to the number of different selected wavelengths;   means for synchronizing the second X-Y scanning beam with the first X-Y scanning beam; and   means for exposing said photographic recording material with said second X-Y scanning beam to record an image thereon representative of the color information derived from said storage medium.   
     
     
       13. The invention of claim 12 wherein said producing means for said second X-Y scanning beam comprises: an acoustooptic cell having electrical-to-acoustical transducer means operably attached thereto;   means for impinging a multi-wavelength beam of laser light upon said cell; and   means comprising a summing amplifier responsive to said modulated electrical signals and interconnected to said transducer means for producing acoustic waves within the cell which diffract the light beams impinging upon the cell to form a composite, collinear output beam comprising wavelengths of light corresponding to said group of different selected wavelengths.   
     
     
       14. The invention of claim 12 wherein said first and second scanning beams are derived from a common laser source and are coupled to a common synchronizing means. 
     
     
       15. An apparatus for recording a color image corresponding to color information on a color storage medium onto color sensitive photographic recording material, said apparatus comprising: means for scanning said storage medium with a multi-wavelength beam of light in a single dimension of scan;   means for moving said storage medium in a direction substantially perpendicular to said dimension of scan to produce an effective X-Y scan of the medium;   means responsive to a number of different selected wavelengths of the scanning beam as modulated by said medium for generating a corresponding number of electrical signals, each of said signals being modulated by a signal of different fixed frequency;   an acoustooptic cell having electrical-to-acoustical transducer means operably attached thereto;   means for impinging a plurality of laser produced light beams of different wavelengths upon said cell;   means responsive to said modulated electrical signals and interconnected to said transducer means for diffracting said multi-wavelength beam of light to produce a composite, collinear output beam of light comprising said different selected wavelengths;   means for moving said collinear output beam in scanning synchronism with the medium scanning means; and   means for exposing said photographic recording material with said collinear output beam to record color images thereon corresponding to the color information on said storage medium.   
     
     
       16. The invention of claim 15 wherein said collinear output beam has a scanning direction corresponding to and synchronized with the scanning direction of said medium scanning beam and the photographic recording material is moved in a direction corresponding to and synchronized with that of said medium. 
     
     
       17. The invention of claim 16 wherein said collinear output beam and medium scanning beams are derived from the same laser source and are responsive to a common synchronizing means. 
     
     
       18. The invention of claim 15 wherein said diffracting means includes: means for summing the plurality of modulated electrical signals of different fixed frequencies to produce said composite, collinear output beam; and   means for varying the amplitudes of said electrical signals of fixed frequencies to control the intensity of said composite, collinear output beam.   
     
     
       19. An apparatus for recording color images corresponding to color information carrying video signals onto motion picture film, said apparatus comprising: laser source means for producing multi-wavelength light;   means for converting video signals carrying color information to electrical signals of different fixed frequencies which are modulated in accordance with the color information carried by said video signals;   means responsive to said electrical signals for diffracting light from said source means into a composite, collinear output beam comprising a number of different selected wavelengths present in said light;   means for moving said collinear output beam so as to produce an X-Y scanning motion of said beam;   means for synchronizing said X-Y scanning motion with said video signals; and   means for exposing motion picture film to said collinear output beam to record images on said film corresponding to said color information.   
     
     
       20. An apparatus for producing a color display comprising: laser source means for producing multi-wavelength light;   means for generating a selected number of electrical signals of different fixed frequencies and for modulating the signals generated thereby;   acoustooptic means optically coupled with said laser means and responsive to said electrical signals for producing a composite, collinear output beam containing a number of different selected ones of the wavelengths present in the light from said laser means; and   means for directing said composite, collinear output beam onto a screen to produce said color display.   
     
     
       21. The invention of claim 20 wherein said beam directing means includes means for scanning said screen with said composite, collinear output beam. 
     
     
       22. A method of producing a composite, collinear beam of light comprising a plurality of different selected wavelengths derived from the wavelengths in one or more laser light sources; the method comprising the steps of: propagating multi-wavelength laser light;   generating a number of electrical signals of different fixed frequencies;   modulating said signals to provide signals of predetermined intensities; and   acoustooptically diffracting said propagated laser light in accordance with said electrical signals to form a composite, collinear output beam comprising a number of different selected wavelengths corresponding in number to said number of electrical signals.   
     
     
       23. The invention of claim 22 wherein propagating laser light comprises propagating a multi-wavelength beam of laser light. 
     
     
       24. The invention of claim 22 wherein propagating laser light comprises propagating at least two wavelengths of laser light. 
     
     
       25. A method for recording a color image corresponding to a color image on a positive transparency onto a color sensitive photographic recording material comprising the steps of: propagating a beam of multi-wavelength laser light;   scanning the transparency with said multi-wavelength beam of light;   receiving the beam as modulated by the transparency;   generating a number of electrical signals of different fixed frequencies, each of which is modulated in accordance with the intensity of a respective one of a corresponding number of different selected wavelengths present in the received modulated beam;   acoustooptically diffracting said propagated laser light in accordance with said modulated electrical signals to form a composite, collinear output beam including said selected wavelengths; and   scanning said photographic recording material with said composite, collinear output beam to form a color image thereon corresponding to the image in the transparency.   
     
     
       26. A method of recording a color image corresponding to a color image in a negative transparency onto a color sensitive photographic recording material comprising the steps of: propagating a beam of multi-wavelength laser light;   scanning the transparency with said multi-wavelength beam of light;   receiving the beam as modulated by the transparency;   generating a number of electrical signals of different fixed frequencies, each of which is modulated in accordance with the intensity of a respective one of a corresponding number of different selected wavelengths present in the received modulated beam;   acoustooptically diffracting said propagated laser light in accordance with said modulated electrical signals to form a composite, collinear output beam including said selected wavelengths; and   scanning said photographic recording material with said composite, collinear output beam to form a color image thereon corresponding to the image in the negative transparency.   
     
     
       27. A method of recording a color image corresponding to a color print onto a color sensitive recording material comprising the steps of: propagating a beam of multi-wavelength laser light;   scanning the color print with said multi-wavelength beam of light;   receiving light reflected from and modulated by the color print;   generating a number of electrical signals of different fixed frequencies, each of which is modulated in accordance with the intensity of a respective one of a corresponding number of different selected wavelengths presented in the reflected modulated light;   acoustooptically diffracting said propagated laser light in accordance with said modulated electrical signals to form a composite, collinear output beam including said selected wavelengths; and   scanning said color sensitive photographic recording material with said composite, collinear output beam to form a color image thereon corresponding to that of the color print.   
     
     
       28. A method of recording color information carried by television signals on color sensitive motion picture film comprising the steps of: propagating a beam of multi-wavelength laser light;   generating a number of electrical signals of different fixed frequencies, each of which is modulated in accordance with the color information carried by the television signals;   acoustooptically diffracting said propagated laser light to form a composite, collinear output beam including a number of different selected wavelengths corresponding in number to said electrical signals; and   scanning the color sensitive motion picture film with said composite, collinear output beam to record a color image on said film in accordance with the color information carried by the television signals. .Iadd. 29. The invention of claim 1 wherein:   said source light comprises at least three input light beams of different wavelengths, each of said input light beams impinging upon said cell at an incident angle different from that of the other input light beams; and   said fixed frequencies are chosen in accordance with said incident angles to form said composite, collinear output beams. .Iaddend.