Abstract: A Raman cell for Raman shifting of a laser pump beam, to an output beam of a different wavelength, the cell containing a gaseous Raman medium at a pressure of 100-1000 PSIG. An input window for a pump beam is located at one end of the cell and an output window for a Raman shifted wavelength output beam is located at the cells opposite end. The output window is formed as a plane mirror having an inner face coated with dielectric thin films which provide a high reflectivity for the wavelength of the pump beam and a partial reflectivity at the cell's Raman shifted wavelength. The input window includes at least one lens that forms a converging lens for the pump beam which has a focal length in the Raman medium of about 3/2 of the cell's inner length to substantially focus the pump beam at the center of the cell after it is reflected back by the inner face of the plane mirror.

Abstract: Optical apparatus having an optical fiber to receive light incident thereon at one end, and a detector located adjacent the other end of the optical fiber to receive light passing through the optical fiber and emitting from the other end thereof to be incident on the detector for analysis purposes.

Abstract: Imaging devices often obtain images of a scene in which portions of the scene are obscured by particles that are interposed between the scene and the camera such as those images obtained when looking through falling snow or through particles stirred up by water currents in an underwater domain. An improved system for reducing the effects of those particles on reconstructed images of a scene consists of obtaining a number of images of a scene and replacing missing elements of the scene, which elements are ones obscured by the particles, with corresponding elements of the scene obtained from previous or following images in which those particular elements of the scene are visible. In this manner, a reconstructed image of the scene can be obtained in which the effects of the particles on the image is greatly reduced.

Abstract: A raman cell oscillator/amplifier arrangement comprising a cell containing a raman high pressure gas or liquid medium with an axicon being located at each end of the cell, one axicon having an input window for a laser pump beam and the axicon at the cell's other end having an output coupler for the raman process converted beam. The axicons directs the laser pump beam towards an extended line focus along the axis of the cell at a shallow angle, the extended line focus for each axicon being collinear with each other to produce an extended raman gain region. By suitable design, it can be ensured that the pump beam energy density at focus is lower than either an optical breakdown or Brillouin backscatter threshold. This provides a means of efficiently producing a raman laser or amplifier having an extended raman gain region without developing problems of optical breakdown, Brillouin backscattering or self-focusing in the case of a liquid raman media.

Abstract: An endoscopic laser instrument is adapted to treat selected areas of body tissue, such as the treatment and evaporation of tumors occurring on the inner of a bladder. The instrument comprises an outer tubular sheath having an optical fiber extending therethrough to emit a laser beam onto an adjustable mirror that reflects the laser beam exiting the fiber to selected areas of the bladder without changing the character of divergence of the beam once it has emerged from the fiber. A standard endoscope viewing optic is mounted in the sheath to permit a surgeon to visually inspect the bladder through a wide visual field. A gas, such as carbon dioxide, is continuously circulated through the instrument and into the bladder for inflation and purging purposes.