United States of America As Represented by the Secretary of the Air Force

Other

Robert D Rathge

LaVerne A Schlie

Gordon D Hager

Philip R Cunningham

Robert F Shea

A repetitively pulsed chemical oxygen-iodine laser having a resonant cavity containing a lasing medium in the form of a flowing mixture of excited oxygen and iodine atoms and an iodine absorption region within the resonant cavity. The iodine absorption region includes a source of iodine atoms and a magnetic field associated therewith. Selectively altering the magnetic field results in changing the absorption characteristics of the iodine atoms and therefore effectively pulses the output of the laser.

Repetitively pulsed Q-switched chemical oxygen-iodine laser

A continuous wave photolytic iodine laser has a gain cell for receiving a continuous supply of gaseous fuel. The gain cell is connected to laser beam transfer optics, a laser resonator for shaping a laser beam, and a lamp. The lamp is driven by a microwave subsystem such that a laser gain medium is pumped through the gain cell. The continuous wave photolytic iodine laser of the present invention incorporates a closed loop fuel system for presenting gaseous fuel to the gain cell at a rate sufficient to sweep any lasing by-products out of the gain cell, thereby preventing quenching of the lasing process. The fuel system also includes a condenser for converting the gaseous fuel to a liquid after it has passed through the gain cell, a scrubber for removing the by-products of the lasing process from the fuel, and an evaporator for converting the recycled liquefied fuel back to a gas. The closed loop fuel system also includes a pump for pressurizing and transporting the liquefied fuel. Provision of pulsed, high energy ultra-violet radiation to the interior gain modules provides a pulsed photolytic iodine laser with a plurality of gain modules, generating very high energy/high power laser output radiation pulses. These output pulses from a laser with a plurality of gain cells can be a frequency greater than 1 Hz.

High power photolytic iodine laser

A high power, closed cycle photolytic atomic iodine laser system having a high molecular weight gas as a laser fuel and which requires a high velocity flow of the laser fuel, the laser fuel to be in a selected low pressure range, and the laser fuel to be of very high purity. The laser system has a turbo-molecular blower for circulating the laser fuel. The turbo-molecular blower provides the high velocity flow, the selected low pressure through the laser gain cell, and a high compression ratio. The velocity is in a range of about 1 m/s to 100 m/s, the compression ratio being in a range from about 10:1 to 1000:1, the selected low pressure in a range of about 5 to 60 Torr, and the turbo-molecular blower not contaminating the laser fuel of the closed cycle fuel system by the use of ferrofluidic rotary seals. The turbo-molecular blower has a blower assembly that provides a continuous, high velocity and pressurized gas flow. The turbo-molecular blower has a housing with at least one inlet and at least one outlet for the laser fuel. The housing has a cooling source thereabout to reduce heating caused by the high molecular weight gas flowing therethrough. The blower has a motor assembly mounted externally to the housing and thereon for powering the rotor of the blower assembly; the motor assembly having a motor of at least one horsepower.

Photolytic iodine laser system with turbo-molecular blower

A repetitively pulsed, high energy, closed cycle photolytic atomic iodine lasers operates at 1.315 microns. Using an iodine (I.sub.2) removal system for the photolyzed C.sub.3 F.sub.7 I laser fuel, more than 70 joules/pulse is output in the fundamental mode from a M=3 confocal unstable resonator at a 0.5 Hz repetition rate. The closed cycle iodine (I.sub.2) removal system consisted of a condensative-evaporative section, two Cu mesh I.sub.2 sections, and an internal turbo-molecular blower. This closed cycle system uses C.sub.3 F.sub.7 I gas at 10-60 torr absent of I.sub.2. The turbo-molecular blower is able to push high molecular weight gases at high velocities. The turbo-molecular blower is able to produce longitudinal flow velocities greater than 10 m/s through the 150 cm long by 7.5.times.7.5 cm.sup.2 cross sectional photolytic iodine gain region. In addition to the high energy output, the resulting 7-12 .mu.sec laser beam has a beam quality less than 1.5 times diffraction limited with a coherence length greater than 45 meters, and a polarization extinction ratio better than 100:1. The laser beam was observed to jitter less than 1 microradian. In order to produce high energies, higher repetition rates, and variable pulse widths, a transverse flow gain cell is employed along with electro-optical switches for the flashlamps.

Repetitively pulsed, closed cycle, photolytic atomic iodine laser

The scalable and stable, cw photolytically excited atomic iodine laser operates at 1.315 nm. An initial power level of 55 watts/liter was obtained via the cw photolysis of an alkyl-iodide gas like C.sub.3 F.sub.7 I. The greatly enhanced laser performance was achieved using a microwave excited, electrodeless Hg plasma lamp excited with a d.c., low ripple cw microwave radiation. Both high flow, air cooling and liquid dimethyl polysiloxane cooling of these high pressure Hg lamps provided long lifetime operation with the latter promoting, stable laser operation. Transverse flow of the above gas for the removal of the quenching by-product I.sub.2 is incorporated into the laser. To insure good laser amplitude stability, both the high power magnetrons and the lamps are liquid cooled. The scalable, prolonged and stable operation of this laser system is possible via use of a closer cycle, condensative/evaporative fuel system coupled to a high flow, internal blower for heavy gases. Over the excitation length of 25 cm, an average small signal gain coefficient of 2%/cm. is produced by exciting the transversely flowing gas from one side. Higher powers are achieveable by exciting the gas from both sides, increasing the ultraviolet lamp radiation with higher microwave power and/or more efficient UV operating plasma lamps, and/or adjusting the UV lamp emission into the C.sub.3 F.sub.7 I absorption in the 240-320 nm region.

Scalable and stable, CW photolytic atomic iodine laser

In a high power microwave excited plasma system including a microwave energy source operatively coupled to a plasma tube for generating a plasma within the tube, a gaseous medium within the tube for supporting a plasma and a reflector for focusing radiation emitted from the tube, an improved cooling system for the tube is provided which comprises a jacket surrounding the tube and defining a passageway therearound, a source of liquid dimethyl polysiloxane, and a circulator for conducting the liquid dimethyl polysiloxane through the passageway in heat exchange relationship with the tube.

Coaxial liquid cooling of high power microwave excited plasma UV lamps

A transverse flow CW atomic iodine laser system uses a closed cycle fuel system to operate in a continuous mode. An elliptical pump cell having a Hg arc lamp cooled by deionized water irradiates with UV energy C.sub.3 F.sub.7 I gas to produce excited atomic iodine. A transverse flow section attached to the pump cell channels C.sub.3 F.sub.7 I gas into a laser cell where lasing occurs. The flow section has upstream and downstream flow cavities, triangular shaped, that channel the laser gas. A diffuser and flow straighteners are placed in these cavities to make the flow velocity across the transverse laser axis as uniform as possible so as to produce very stable laser gain output.

Growing community of inventors

Albuquerque, NM, United States of America

Robert D Rathge