Abstract: A flashlamp system is described which permits the use of flashlamp tubes of increased diameter for higher average power capability while retaining the desirable characteristics of a small diameter, wall stabilized tube which includes small image size, short pulse duration and high ionization level. A series of low level pre-pulses are applied to the flashlamp prior to a main pulse to form a low density region along the flashlamp discharge axis for the main pulse for generating radially directed acoustic waves, thereby to confine the main discharge to a small low density region near the tube center. When Xenon flashlamps are used, this results in a higher ionization level of the molecules along the axis of the flashlamp which increases the ratio of the short-lived XeII emission to long-lived continuum, thereby effectively reducing pulse duration.

Abstract: The problems of collimating, synchronizing and combining a plurality of laser beams to generate a composite beam are substantially reduced by the use of one or more lasers especially adapted to lase in two or more separate wavelengths. Specifically, a composite beam generating system comprises at least one multiwavelength laser for emitting a multiwavelength beam having at least two separated wavelength components, one or more additional lasers for generating respective additional beams, and means for combining the multiwavelength beam with one or more additional beams. In a preferred embodiment, a four-component multiwavelength composite beam is generated by polarization combination of the outputs of a pair of orthogonally polarized two-component multiwavelength lasers.

Abstract: A CO.sub.2 medium is optically pumped by a five micron CO laser to the 03'0 level which radiates with 16 micron emission to the 02.degree.0 level. The resulting 16 micron laser finds application in laser uranium enrichment operating to provide excitation of uranium hexafluoride particles. Terminal level blockage, or bottlenecking, in the 02.degree.0 level is optionally avoided for continuous mode operation by 10 micron excitation with a CO.sub.2 laser from the 02.degree.0 to the 00.degree.1 level. The CO.sub.2 is then diluted by mixing nitrogen gas with it to promote energy transfer to the V=1 vibrational level of the nitrogen, thereby insuring maintenance of the inversion necessary for efficient, high power lasing in the 03'0 to 02.degree.0 transition.

Abstract: A CO.sub.2 laser capable of emitting at 16 microns in the transition from the 02.degree.O to the 01'0 energy levels. The laser is particularly adaptable for use in laser enrichment to photoexcite uranium hexafluoride molecules. The CO.sub.2 medium is originally excited to many levels above and including the 02.degree.0 level. De-excitation to the 02.degree.0 level is induced from several upper levels populating it highly for improved laser gain. The transition between the 02.degree.0 and 01'0 levels at 16 microns is then permitted by depopulating the 01'0 level with 5 micron radiation from a CO laser. In the preferred case, excitation of the CO.sub.2 medium is by an electronic discharge, and all levels are excited from the ground state by the discharge without selectivity. The pumping from the terminal 01'0 level maintains the inversion for 16 microns lasing.

Abstract: A system for frequency locking the output of one or many laser amplifiers to a reference laser oscillator beam without injection of the reference beam into the amplifier medium. This avoids the necessity of exciting at the frequency of the desired output and of beam splitting from the oscillator to inject a portion of the oscillator radiation into each of several controlled amplifiers. The amplifier includes a lasing medium confined within a cavity and having a portion of the radiation in the medium directed onto a closed loop. A frequency selecting element is supplied within the closed loop and controlled electronically to maintain a predetermined frequency relationship to the laser beam of the reference laser oscillator. Radiation in the closed loop is thus controlled in frequency and a portion of it within the amplifier medium is diverted for repeated medium traversals in an unstable cavity configuration to achieve a desired amplification and pulse elongation.