Resonant acousto-optical device

Claim 2

An acousto-optical device for intermittently transmitting a light beam comprising: a body of photoelastic material transparent to the wavelength of the light beam to be transmitted, said body of photoelastic material being shaped so as to provide a resonant cavity for acoustic waves; means for generating a beam of acoustic waves in said body of photoelastic material at one of the resonant frequencies thereof, the direction of propagation of said beam of acoustic waves being such as to cause Bragg scattering of the light beam; and means for interrupting said beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said resonant cavity so that corresponding transmitted interruptions meet reflected interruptions to provide gaps in said beam of acoustic waves in order to permit said light beam to be transmitted through said body of photoelastic material when said gaps coincide with said light beam.

Claim 3

The acousto-optical device of claim 1, wherein said body of photoelastic material is in the form of a rectilinear solid.

Claim 4

The acousto-optical device of claim 2, wherein said means for generating a beam of acoustic waves comprises an electro-mechanical transducer mounted on one end of said rectilinear body of photoelastic material, and a single generator connected to said electro-mechanical transducer for driving said electro-mechanical transducer to generate resonant acoustic waves in said rectilinear body of photoelastic material.

Claim 5

The acousto-optical device of claim 3, wherein said electro-mechanical transducer comprises a piezoelectric crystal.

Claim 6

The acousto-optical device of claim 3, wherein said electro-mechanical transducer and rectilinear body of photoelastic material act as a frequency determining element of said signal generator.

Claim 7

The acousto-optical device of claim 3, wherein said means for interrupting said beam of resonant acoustic waves comprises means for inhibiting the signals from said signal generator to said electro-mechanical transducer, and timing means for operating said inhibiting means twice during each time interval required for said acoustic waves to traverse said resonant cavity.

Claim 8

The acousto-optical device of claim 6, wherein said timing means operates said inhibiting means to inhibit the signals from said signal generator to said electro-mechanical transducer twice during a time period T 2L/v where v is the velocity of the acoustic waves in the body of photoelastic material and L is the length of said resonant cavity.

Claim 9

The acousto-optical device of claim 7, wherein said timing means operates said inhibiting means to inhibit the flow of signals from said signal generator to said electromechanical transducer once during each time period T L/v where v is the velocity of the acoustic waves and L is the length of said resonant cavity.

Claim 10

The acousto-optical device of claim 1, wherein said means for interrupting said beam of acoustic waves operates to interrupt said beam of acoustic waves for time intervals commensurate with the rise time of laser oscillations.

Claim 11

An acousto-optical device for intermittently transmitting a light beam comprising: a body of photoelastic material transparent to the wavelength of the light beam to be transmitted, means for generating a first beam of resonant acoustic waves in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said body of photoelastic material being shaped so that said beam of acoustic waves propagated by said first beam generating means are reflected from an interior surface of said body of photoelastic material and are returned to said first beam generating means along a first predetermined path; means for generating a second beam of resonant acoustic waves in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said body of photo-elastic material being shaped so that said beam of acoustic waves generated by said second beam generating means are reflected from an interior surface of said body of photoelastic material and are returned to said second beam generating means along a second predetermined path, the length of said second predetermined path being different from the length of said first predetermined path; means for interrupting said first beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said first predetermined path; and means for interrupting said second beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said second predetermined path, whereby said light beam is transmitted through said body of photoelastic material when transmitted and reflected interruptions in said first and second acoustic beams coincide with said light beam.

Claim 12

An acousto-optical device for intermittently transmitting a light beam comprising: a body of photoelastic material transparent to the wavelength of the light beam to be transmitted, means for generating a first beam of resonant acoustic waves in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said body of photoelastic material being shaped so that said beam of acoustic waves propagated by said first beam generating means are reflected from an interior surface of said body of photoelastic material and are returned to said first beam generating means along a first predetermined path; means for generating a second beam of resonant acoustic waves in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said body of photo-elastic material being shaped so that said beam of acoustic waves generated by said second beam generating means are reflected from an interior surface of said body of photoelastic material and are returned to said second beam generating means along a second predetermined path, the length of said second predetermined path being different from the length of said first predetermined path; means for interrupting said first beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said first predetermined path; and means for interrupting said second beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said second predetermined path, whereby said light beam is transmitted through said body of photoelastic material when transmitted and reflected interruptions in said first and second acoustic beams coincide with said light beam.

Claim 13

The acousto-optical device of claim 10, wherein the difference between the length of said first predetermined path and the length of said second predetermined path is greater than the product of the velocity of the acoustic waves in said body of photoelastic material and the length of said predetermined time interval for which said acoustic waves are interrupted by said interrupting means.

Claim 14

The acousto-optical device of claim 10, wherein said first and second means for interrupting said beams of acoustic waves operate to interrupt said beams of acoustic waves for time intervals commensurate with the rise time of laser oscillations.

Claim 15

The acousto-optical device of claim 10, wherein said body of photoelastic material is in the form of a rectilinear solid.

Claim 16

The acousto-optical device of claim 13, wherein said first and second beam generating means comprise electromechanical transducers mounted on one end of said rectilinear body of photoelastic material, and signal generators connected to said electro-mechanical transducers for driving said electromechanical transducers to generate beams of acoustic waves in said rectilinear body of photoelastic material.

Claim 17

The acousto-optical device of claim 14, wherein said electro-mechanical transducers comprise piezoelectric crystals.

Claim 18

The acousto-optical device of claim 14, wherein said electro-mechanical transducers and rectilinear bodies of photoelastic material act as frequency determining elements of said signal generators.

Claim 19

The acousto-optical device of claim 10, wherein said means for interrupting said first beam of acoustic waves operates to interrupt said first beam of acoustic waves twice during a period T 2L1/v where 2L1 is the length of said first predetermined path and v is the velocity of acoustic waves in said body of photoelastic material.

Claim 20

The acousto-optical device of claim 17, wherein said means for interrupting said second beam of acoustic waves operates to interrupt said second beam of acoustic waves twice during a time period T 2L2/v where 2L2 is the length of said second predetermined path and v is the velocity of acoustic waves in said body of photoelastic material.

Claim 21

The acousto-optical device of claim 18, wherein said means for interrupting said first and second acoustic beams operate to interrupt said first and second acOustic beams for pairs of intervals separated by a time equal to 2L0/v where L0 is the distance from said first and second beam generating means to the path of said light beam and v is the velocity of acoustic waves in said body of photoelastic material.

Claim 22

An acousto-optical de3ice for intermittently transmitting a light beam comprising: device a body of photoelastic material transparent to the wavelength of the light beam to be transmitted, means for generating a first beam of acoustic waves in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said body of photoelastic material being shaped so as to provide a resonant cavity for said first beam of acoustic waves; means for periodocally interrupting said beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said resonant cavity so that corresponding transmitted interruptions meet reflected interruptions at the path of the light beam to be transmitted; means for generating acoustic pulses in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said acoustic pulses being synchronized to coincide with sqid interruptions in said acoustic beam at the path of the light beam to be transmitted; an acoustic absorber mounted on said body of photoelastic material for absorbing said acoustic pulses; and means for selectively suppressing said acoustic pulses to permit transmission of the light beam.

Claim 23

An acousto-optical de3ice for intermittently transmitting a light beam comprising: device a body of photoelastic material transparent to the wavelength of the light beam to be transmitted, means for generating a first beam of acoustic waves in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said body of photoelastic material being shaped so as to provide a resonant cavity for said first beam of acoustic waves; means for periodocally interrupting said beam of acoustic waves for a predetermined interval twice during each time period required for said acoustic waves to traverse said resonant cavity so that corresponding transmitted interruptions meet reflected interruptions at the path of the light beam to be transmitted; means for generating acoustic pulses in said body of photoelastic material in a direction such as to cause Bragg scattering of the light beam to be transmitted, said acoustic pulses being synchronized to coincide with sqid interruptions in said acoustic beam at the path of the light beam to be transmitted; an acoustic absorber mounted on said body of photoelastic material for absorbing said acoustic pulses; and means for selectively suppressing said acoustic pulses to permit transmission of the light beam.

Claim 24

The acousto-optical device of claim 20 wherein said acoustic pulse generating means normally generates an acoustic pulse periodically during each time period required for said beam of acoustic waves to traverse said resonant cavity.

Claim 25

The acousto-optical device of claim 20 wherein the width of said acoustic pulses is substantially equal to said predetermined intervals of interruption of said acoustic beam.

Claim 26

The acousto-optical device of claim 22 wherein said predetermined intervals are commensurate with the rise time of laser oscillations.

Claim 27

The acousto-optical device of claim 20 wherein the portion of the surface of said body of photoelastic material in the path of said acoustic pulses is disposed at an angle incommensurate with 360* to the direction of propagation of said acoustic pulses.