Abstract: An improved electro-optic modulator having reduced amplitude of acoustic resonances is provided. Acoustic energy is efficiently removed from the electro-optic crystal and channeled into electrode and side dielectric bars where it is dissipated by materials acoustically matched to the electro-optic crystal, that is, materials that have acoustic impedances within .+-.15% of that of the electro-optic material.

Abstract: A waveguide coupler for coupling electromagnetic power between a first rectangular waveguide and a second rectangular waveguide includes a one-dimensional intermediate waveguide formed of two plates spaced apart by a distance equal to a common height of the two waveguides. This enables a wave emanating from the first waveguide to spread apart transversely so as to equal the width of the second waveguide, the width of the second waveguide being greater than the width of the first waveguide. A cylindrical lens is located between the intermediate waveguide and the second waveguide to provide for a conversion between a cylindrical wavefront and a planar wavefront. The coupler is operative in reciprocal fashion such that a wave emanating from the first waveguide spreads out in width and is then converted to a planar waveguide prior to entering the second waveguide; and a wave emanating from the second waveguide is converted to a wave of contracting width for entry into the first waveguide.

Abstract: This invention discloses a narrow field of view scanner (10) incorporating two multi-faceted polygon scanning wheels (12, 16) having a slightly different number of facets (14, 18). Each scanning wheel (12, 16) turns at an angular rate such that a facet (14) on one wheel (12) rotates through a predetermined field of view at the same rate as a facet (18) on the other wheel (16). Further, each of the scanning wheels (12, 16) scan in opposite scanning directions. This does not necessarily mean, however, that the wheels are actually rotating in opposite directions. Because both of the scanning wheels (12, 16) are scanning in opposite directions, the scanning of one scanning wheel (16) substantially cancels the scanning of the other scanning wheel (12). Because of the difference in the number of facets (14, 18) between the two scanning wheels (12, 16), the scanning is not entirely cancel out.

Abstract: A method and apparatus which corrects the amplutide variation in the output in an electro-optic modulated laser system (10). Birefringence within the electro-optic crystal (25) causes elliptical polarization of the linearly polarized laser light (22) produced by the laser gain medium (16), in turn causing a loss in the laser output (27). The loss owing to the elliptical polarization is corrected by either applying a D.C. bias from voltage source (30) directly to the electro-optic crystal (25) or by inserting a quarter-wave plate (32) within the laser's resonant cavity.

Abstract: A method and improved apparatus for aligning a diffraction grating, as, for example, one used in tuning the output of a laser. The total angular misalignment .epsilon. between the incident and diffracted beams is a function of three angles: the tuning angle .theta.16, the angle of tilt .beta. between the plane of the grating 15 and the tuning rotational axis, and the angle .alpha. between the grating lines and the projection of the turning rotational axis in the plane of the grating 15. The present invention provides a method of aligning the diffraction grating so that the residual alignment error is very small over the desired range of tuning angle .theta. 16, by adjusting only .alpha. or only .beta. to zero at two reference tuning angles .theta..sub.0 and .theta..sub.1. Knowledge of the value of either .alpha. or .beta. is not necessary. For a CO.sub.2 laser tuned over the wavelength range 9.11 to 10.88 .mu.

Abstract: A reflectance-outcoupled laser resonator 10 with an improved electro-optical Q-switch 13, 18,19, 21 is disclosed which is alignment stable. The laser performance is insensitive to angular movements of the resonator elements. This resonator requires fewer optical components and lower total cost than other resonators which are designed to perform similar functions. The invention includes a laser medium 12, two prisms 13, 21, a polarizer 18, an electro-optic crystal 19, and an alignment wedge 20. A polarization preserving folding prism 13 allows great flexibility in resonator design by passing any arbitrary polarization state without change. A double end-reflector prism 21 serves as both cavity end reflectors of the resonator and also serves as a component of the Q-switch 13, 18, 19, 21.