United Technologies Corporation

Jack W Davis

Paul R Blaszuk

Clyde O Brown

Alan C Eckbreth

A CO.sub.2 gas laser is equipped with a gas mixture control arrangement which introduces into the interior of the laser, of the constituent component of water, only hydrogen, in such amounts based on the instantaneous humidity of the gas mixture that the dew point of water vapor resulting from the combination of the thus introduced hydrogen with incidental oxygen present in the laser interior as an incident to the operation of the laser is maintained within a predetermined range.

Laser gas composition control arrangement and method

A damage resistant laser mirror is disclosed comprising a copper substrate highly polished to an optical finish coated with a thin layer of molybdenum or tungsten. The composite has good reflecting properties, is damage-tough, and conducts heat well away from the reflective coating. The superior adhesion of the coating is demonstrated by the fact that severe staining can be removed from the surface of the mirror by abrasive polishing without removing or damaging the coating.

Damage resistant coated laser mirror

An apparatus adapted for rotating a beam of radiation to obtain azimuthal and radial time averaging of the intensity distribution incident onto a workpiece is disclosed. The apparatus includes a housing adapted for rotation about a centerline axis, an entrance port and an exit port adapted for transmitting a beam of radiation through the housing, an inverter disposed within an internal passage within the housing and fixedly attached to the housing for rotation therewith includes a first mirror having a reflective surface angularly disposed to the rotation axis adapted for reflecting radiation incident thereon to a second mirror, a second mirror having a reflective surface adapted for reflecting radiation incident thereon to a third mirror having a reflective surface angularly disposed to the rotation axis adapted for passing radiation incident thereon through the exit port. Radiation passing through the housing is rotated about its propagation axis at an angular frequency twice the angular rotation rate of the housing. In one embodiment the third mirror has its centroid displaced from the centerline axis such that each ray in the rotating beam traces out an epicycloid instead of a circle thus averaging out some of the radial variations in the intensity distribution. The effect of spikes, hot spots, or the like in the intensity distribution are effectively time averaged over an interaction area on a workpiece when the rotation frequency is greater than the characteristic response time of the material of the workpiece.

Reflective beam rotator

Discharge electrodes suitable for CO.sub.2 and other electrically excited gas lasers are improved by the substitution of a single row of electrodes having an emissive area greater than the pin electrodes of the prior art and being spaced a greater distance upstream from the power electrodes.

Laser discharge electrode configuration

In an optical system, primarily adapted for use in light scattering diagnostics e.g. Raman, Rayleigh, laser fluorescence, an obscuration means is placed between the sample volume (or object) and a light collecting means (such as a lens or mirror) to limit the backscattered light collection passed through an aperture to a shorter length along the optical axis, thereby increasing the spatial resolution of the system. In general, the effective obscuring diameter is determined as twice the ratio of the square of the distance between the image of the aperture within the sample volume and the collection means to the distance between the collection means and the aperture, times the ratio of the aperture diameter to the desired length of sample volume. In refractive embodiments, obscuration is provided by an opaque disc adjacent a collection lens. In a second embodiment, obscuration is provided by a coaxial arrangement of independent fiber optical light pipes. In a third embodiment, Cassegrainian-type reflection optics are used.

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East Hartford, CT, United States of America

Jack W Davis