公开(公告)号：CA861739A

公开(公告)日：1971-01-19

申请号：CA861739D

Applicant: IBM

Inventor： WIEDER HAROLD ,  MYERS ROBERT A

公开(公告)号：DE1639264A1

公开(公告)日：1970-07-09

申请号：DE1639264

申请日：1968-01-10

Applicant: IBM

Inventor： ANTHONY MYERS ROBERT ,  WIEDER HAROLD

IPC: H01S3/101 ,  G02F1/28

Abstract: 1,139,970. Lasers. INTERNATIONAL BUSINESS MACHINES CORP. 5 Jan., 1968 [13 Jan., 1967], No. 734/68. Heading H1C. A laser includes an angularly degenerate resonant cavity comprising a first reflecting surface 11 and an electro-optical element 20 presenting a second reflecting surface 21, the refractive index of a selected portion or portions of the element being variable in such a way that stimulated emission occurs from a laser active medium 10 in the cavity along a selected path or paths. Fig. 1, shows a scanner. Element 20 has a dielectric reflecting surface 22 spaced from the conducting reflective surface 21 such that the element defines an etalon normally resonant at the output wavelength of the laser. The element is formed as the face of a cathode ray tube 23 which can be controlled to direct electrons on to a selected portion of surface 22. The resulting local electric field changes the refractive index of a portion of element 20 so that it is no longer resonant near this portion. The corresponding portion of surface 21 then becomes highly reflective and forms a high- Q resonant cavity with its own image in mirror 11. All other possible modes remain in low-Q conditions and are suppressed. The initial resonant condition of element 20 is adjusted by controlling its temperature, or the initial mechanical or electrical stress applied to it. In Fig. 2 two laser cavities have a common electro-optical element 30, which is in this case normally non-resonant so that the cavities are not coupled. Laser A is pumped above its lasing threshold, whereas laser B is just below threshold. When a region of dielectric reflector 35A is selected by an electron beam from 37 or 39 the etalon becomes resonant in this region, and the two cavities are coupled for a mode which resonates in the cavity between mirrors 31A and 31B and through the " window " formed in element 30. Mirror 31B (or 31A) is partially transparent. The provision of two electron guns 37, 39 permits the performance of logic. Since the etalon formed by element has a series of transmission peaks corresponding to different electric field strengths it is possible to open a " window " with an electron beam from one gun (binary 1), to close it again with a second beam (binary 0), and re-open it with a third (binary 1), there being a delay between the placing of a charge on the element and its decay. Instead of using an electron beam the dielectric reflector 22 or 35A may be replaced by a mosaic of conductive and reflective areas, each connected individually to a voltage source.

公开(公告)号：DE1949026A1

公开(公告)日：1970-04-09

申请号：DE1949026

申请日：1969-09-27

Applicant: IBM

Inventor： WIEDER HAROLD

IPC: H01S3/10 ,  G02F1/03 ,  G02F1/05 ,  H01S3/00 ,  H01S3/06 ,  H01S3/08 ,  G02F1/00

Abstract: 1,251,590. Lasers. INTERNATIONAL BUSINESS MACHINES CORP. 27 Aug., 1969 [30 Sept., 1968], No. 42564/69. Heading H1C. An image converter comprises a multimode He-Ne laser 12 having the end mirrors 24, 26 of its resonant cavity reflective to visible radiation but transparent to infra-red radiation to give a visible output, some of the modes being depopulated by an incoming infra-red image 15 so that the visible output is the negative of this image. The infra-red image of object 14 may first be amplified in intensity by one or more He-Ne lasers 10 having lenses 16, 20 separated by twice their focal distance f. A lens 22 backing mirror 24 directs the image into the laser cavity 12, in which there are of the order of 10 6 transverse modes, and lenses 28, 30 project the image on to mirror 26. This latter mirror is partially transmitting to visible radiation, and the visible output is projected on to a screen 36 by lens 34. Those modes occupying the same spatial positions as the incoming infra-red image are depopulated, and since He-Ne media have a greater gain at infra-red frequencies than in the visible spectrum, the output from modes depopulated by intense parts of the image is wholly infra-red. In less intense areas of the image, only a part of the output from such modes is infra-red, and hence the visible output on screen 36 is the complement of the infra-red input image. Mirror 26 may be made reflective to infra-red radiation so that the incoming image passes through cavity 12 twice. Other active media in which the gain is greater in the infra-red than in the visible waveband may be used, such as ionized mercury.