A device is disclosed for producing a pair of synchronized intense 16 micron pulses in which stimulated rotational Raman scattering together with four wave mixing and pulse compression takes place in parahydrogen on an off-axis path between a pair of spherical mirrors.

An optically pumped atomic iodine laser with a lasing cavity formed by a sealed cell containing iodine vapor as the lasing medium. A tunable dye laser having an output wavelength in the 493-501 nm range is oriented so that its beam is directed into the lasing cavity. This pumps the iodine vapor and results in its dissociation into an atomic iodine medium that lases at 1.315 microns. An optical cavity is formed by two mirrors mounted around the sealed cell on the optical axis of the lasing cavity in a substantially confocal configuration. The two mirrors are more than 99.9% reflective of radiation emitted by the lasing iodine vapor, but pass more than 80% of the radiation from the dye laser. A total reflector to radiation from the dye laser is positioned outside the optical cavity to reflect radiation from the dye laser back through the lasing cavity. Mode matching lenses are mounted between the dye laser and the sealed cell to shape the dye laser beam to the approximate mode shape of the lasing cavity. The iodine laser output beam is passed through a long pass filter to remove any remaining dye laser beam. This laser is capable of indefinite use without replenishment of the lasing medium and the wavelength of its output beam is independent of the wavelength of the pumping beam from the dye laser.

Apparatus for producing tunable intense coherent radiation at approximately 628 cm..sup.-1 with a line width less than 0.1 cm..sup.-1. The apparatus includes an optical cavity containing a vapor cell and pumping means including at least one optical pumping source for directing energy at the cavity. In one embodiment the cavity encloses a material capable of stimulated emission in response to said pumping. The material has at least three atomic energy levels with at least a first and second atomic energy level separated by a particular energy quantum approximately equal to 628 cm.sup.-1 ; a transition from said first to said second atomic energy level favored over all other possible transitions from said first atomic energy level; said third atomic energy level, from which atoms can be pumped to said first atomic energy level in response to said pumping means. While this is consistent with classical laser operation the apparatus disclosed herein can also be used for stimulated Raman scattering. Tunability is achieved by tuning the pumping sources in the case of stimulated Raman scattering, or with the aid of the Zeeman or Stark effects for classical laser operation. Typical materials are potassium or strontium vapors. Several pumping arrangements are also disclosed.

An improved wick for a metal vapor laser is made of a refractory metal cylinder, preferably molybdenum or tungsten for a copper laser, which provides the wicking surface. Alternately, the inside surface of the ceramic laser tube can be metalized to form the wicking surface. Capillary action is enhanced by using wire screen, porous foam metal, or grooved surfaces. Graphite or carbon, in the form of chunks, strips, fibers or particles, is placed on the inside surface of the wick to reduce water, reduce metal oxides and form metal carbides.

Apparatus performs a method of generating one output laser pulses in a range of 2 to 5 microns using an intracavity feature. When a plurality of the output laser pulses are generated, a first output pulse may have any selected wavelength within the range and a second output pulse is temporally closely spaced relative to the first output pulse and may have a chosen wavelength differing from the selected wavelength. A pump laser cavity is provided with a tunable rod and an intracavity Raman device (in the pump cavity) to shift the wavelength of initial pump laser pulses. The intracavity Raman device generates radiation at first and second Stokes wavelengths, and the pulses at each wavelength are separated and are in separate paths for permitting separate operation thereon. The Raman device in the pump cavity increases the pump intensity inside the Raman cell and gives a much longer effective interaction length between the pump laser beam and the Raman medium. A first Stokes cavity for the first Raman shift overlaps the pump cavity such that the intensity in the first Stokes cavity is increased. A second Stokes cavity overlaps the pump cavity and is provided with one highly reflecting end mirror and one partially reflecting end mirror which serves as an output coupler for the output pulse which is in the wavelength range from 2 to 5 microns.