A pulsed ruby laser is caused to oscillate substantially in a single mode to increase its coherence length. This is accomplished by the provision of one or more dye cells containing chlorophyll d as a saturable absorber for the laser radiation. The dye cell has a length of no less than one-quarter and no more than two-thirds that of the optical laser cavity and preferably has a length of approximately one-half that of the cavity. Due to the provision of such a long chlorophyll d dye cell the ini...

Holographic contour maps with closed controllable spacing of the range contours are made with one or two ruby lasers. For example, two ruby lasers may be provided, each being operated at a different temperature so as to illuminate the object with two separate frequencies. Alternatively, one of the rods may consist of pink ruby and the other of dark ruby. Also, two separate exposures may be taken, each being made with the ruby laser operated at a different frequency. This may be accomplished by s...

In a time-variable reflectivity laser of the type having a cavity, total reflection mirrors at the ends of the cavity, a ruby rod in the cavity for emitting radiation, a xenon lamp for pumping the ruby rod, a Glan polarizer in the cavity, a cell having electrodes in the cavity for changing the polarity of light, and apparatus for energizing the energy source and for energizing and deenergizing the cell in a predetermined sequence to discharge light from the cavity. The energizing apparatus consi...

A multifrequency laser oscillator which generates coherent light of two closely adjacent optical frequencies in rapid succession for recording contour holograms by the double exposure technique. The two light frequencies are selected by an optical intercavity frequency selector which is rotatable to a first position to select one frequency and to a second position to select the other frequency. The described laser oscillators have a ruby lasing medium and lase at the R.sub.1 and R.sub.2 transiti...

A multifrequency laser oscillator which generates coherent light of two closely adjacent optical frequencies in rapid succession for recording contour holograms by the double exposure technique. The two light frequencies are selected by a pair of frequency selecting reflectors at one end of the oscillator resonator cavity. At least one of these reflectors is movable between an active position where it reflects the laser beam to select one light frequency and an inactive position where the other ...

A laser of the type which generates linearly polarized light and including optical means for self-alignment. Among such polarized lasers are, for example, solid state lasers and particularly ruby lasers, as well as various gas lasers employing Brewster windows. The problem is solved by utilizing a corner reflector in the laser cavity which generates two parallel laser beams. In order to achieve effective laser operation the polarization determining aspect of the laser, that is the crystal axis o...

A ruby or other solid laser is made to generate two or more closely adjacent optical frequencies. By illuminating an object to be recorded holographically with the laser light, range contours are generated when the hologram is reconstructed. The range contours can be made to have distances on the order of 5 millimeters or more by utilizing a ruby laser. To this end, one of the two boundaries of the optical cavity for the laser is formed by a suitable mode selector, such, for example, as a Fabry-...

Holographic apparatus for taking holograms in transmission with lasers of limited coherence permitting a wide-viewing angle on the order 50.degree. to 60.degree.. The apparatus features an angle between the reference and scene beams, at the hologram, on the order of 90.degree.. Once the laser beam is enlarged and collimated there is no need for any additional lenses in the path of the reference beam. The scene beam includes a diffuser and a lens system between the light diffuser and the object b...

A standing light wave within the active lasing medium of a laser oscillator is avoided, to prevent periodic bleaching of the medium and thereby foster single mode oscillation and improve coherence. The coherent light propagating from each end of the lasing medium is directed to the opposite end of the medium through a ring resonator cavity with an optically folded portion having a region through which the light waves propagating in each direction around the cavity travel first in one direction a...

A standing lightwave within the active lasing medium of a laser oscillator is avoided to prevent periodic bleaching of the medium and thereby foster single mode oscillation and improve coherence. A Faraday isolator and an optical rotator located within the opposite end regions of the laser resonator cavity, between the lasing medium and cavity end reflectors, changes the direction of polarization of the coherent light propagating through these cavity regions and blocks oscillation of light which...