公开(公告)号：DE1956747A1

公开(公告)日：1970-06-11

申请号：DE1956747

申请日：1969-11-12

Applicant: IBM

Inventor： WILLIAM SMITH ARCHIBALD

IPC: H01S3/08 ,  G01B9/02 ,  G02F1/29 ,  G02F1/33 ,  G06K7/12 ,  G11C13/04 ,  H01S3/098 ,  H01S3/101 ,  H04N3/12 ,  H01S3/10

Abstract: 1280520 Modulating light INTERNATIONAL BUSINESS MACHINES CORP 15 Oct 1969 [13 Oct 1968] 50567/69 Heading H4F [Also in Divisions G2 and H1] An optical device includes means for providing an ordered array of coherent light beams, the beams being separated in space and frequency by equal distances and by equal frequency differences respectively, and means for combining the beam so that a moving interference pattern is obtained. The interference pattern is caused to move along a linear path. In one embodiment (Fig. 3) the plurality of beams 34-1, 34-n is produced within the laser cavity, an aperture plate 44 being provided for this purpose. A linear variation in cavity length is provided by a step tuning wedge 33. The ordering to give the predetermined phase and equal frequency differentials is by an acoustic wave modulator 36. This may lock only transverse modes, or, if present, both transverse and longitudinal modes. In an alternative embodiment a beam 102 (Fig. 5) from a single laser 100 is circularly polarized and after reflection from a partially reflecting mirror 106 is reflected by three other mirrors 108, 110, 112 to give the ordered array. The frequency differences are caused by frequency shifters 122, 124 (electro-optic devices), a lens 126 combining the beams to move from the moving interference pattern along a line 130. In a further embodiment the separate beams emanate from separate lasers. Alternatively a single longitudinal and transverse mode laser beam (Fig. 4, not shown) passes an acoustic wave modulator operable at a given frequency. A mirror configuration co-operates with the acoustic wave modulator to provide the plurality of beams. The modulator has an antireflective coating on a surface facing a mirror of the configuration.

公开(公告)号：DE1764153A1

公开(公告)日：1971-05-13

申请号：DE1764153

申请日：1968-04-11

Applicant: IBM

Inventor： BURNS GERALD ,  WILLIAM SMITH ARCHIBALD

IPC: H01S3/101 ,  H01S3/10

Abstract: 1,147,587. Lasers. INTERNATIONAL BUSINESS MACHINES CORP. 12 March, 1968 [13 April, 1967], No. 11874/68. Heading H1C. A laser beam is emitted in a required direction by transmitting an ultrasonic beam transverse to the plurality of resonant paths in a degenerate optical resonator, the ultrasonic beam causing that resonant path which is diffracted at the Bragg angle to become effective. Scanning is effected by changing the frequency of the ultrasonic beam so that a different resonant path is diffracted at the Bragg angle. The ultrasonic beam may be propagated through the active medium 6, Fig. 1, which may be ruby, neodymium-doped yttrium aluminium garnet or suitably doped LiNbO 3 , or the beam may be transmitted through an ultrasonic medium 26, Fig. 2, separate from a ruby or a gaseous active medium 25. The degenerate resonator is formed in Fig. 1 by spherical mirrors 2, 4, and the active medium 6 is provided with curved surfaces 16, 18 which assist in focusing laser light in the resonator on to the spherical mirrors. The ultrasonic beam is produced in the active medium by applying a signal from a high frequency oscillator 10 to a zinc oxide or cadmium sulphide transducer element 8 cemented or vapour deposited on the active medium, the transmitted ultrasonic beam being absorbed on the other side of the active medium by an absorber 12 such as glass. A transducer element is unnecessary if the active medium has piezo-electric properties, e.g. a suitably doped LiNbO 3 crystal. In Fig. 2 the resonator is formed by a spherical mirror 2 incorporating an operative stop 32 and a plane mirror 24, the arrangement in association with a lens 30 providing separate paths for each direction of light diffracted in the separate fused quartz or water ultrasonic medium 26, the arrangement neutralizing a shift in the laser light frequency which would otherwise be obtained. Two dimensional scanning may be obtained by using two orthogonal ultrasonic media.

公开(公告)号：DE1764270A1

公开(公告)日：1971-06-16

申请号：DE1764270

申请日：1968-05-07

Applicant: IBM

Inventor： STEVENS SHIREN NORMAN ,  WILLIAM SMITH ARCHIBALD

IPC: G02F1/09 ,  G02F1/33 ,  G02F

公开(公告)号：DE1937842A1

公开(公告)日：1970-02-12

申请号：DE1937842

申请日：1969-07-25

Applicant: IBM

Inventor： BURNS GERALD ,  WILLIAM SMITH ARCHIBALD ,  VICTOR SHMITH WILLIAM

IPC: G02F1/05 ,  G09G3/34 ,  G11C11/22 ,  G11C11/23 ,  G11C13/04

Abstract: 1,253,168. Modulating light. INTERNATIONAL BUSINESS MACHINES CORP. 22 July, 1969 [7 Aug., 1968], No. 36770/69. Heading H4F. [Also in Division G4] An optical switch which may be used as a memory element comprises means for applying an electric field across a crystal of Gd 2 (MoO 4 ) 3 , parallel to its c-axis, the crystal being ferroelectric and showing reversible birefringence, i.e. it will remain in one of two birefringent states depending on the polarity of the last applied electric field above a threshold (switching) value, the two states being related in that the fast and slow axes are interchanged. In one embodiment the crystal is provided with transparent silver electrodes and forms a quarterwave plate so that linearly polarized input light emerges as circularly polarized, of a hand dependent on the state of the crystal. A further quarter-wave plate and an analyser will then block or pass the emergent light to a detector. An X-Y addressable array of such cells is also described and shown, and the subsequent quarter-wave plate and analyser may be formed as a unitary film over the array. In a second embodiment, one electrode is reflective, e.g. silver or copper, and the other is in the form of strips or is transparent, so that linearly polarized laser light directed by a beam splitter through the crystal is reflected back through the splitter with left or right circular polarization. An electron gun charges the reflective electrode either negatively, with a low voltage beam, or positively, by secondary emission, using a higher energy beam, and so switches the crystal. Light from the beam splitter is again passed through a quarter-wave plate and analyser. An array of such memory cells may be operated by a single electron beam and the analysed light passed to the photo-conductive layer of an electron beam scanning tube.