摘要:
The high power laser includes a high gain medium (>80%) such as a lightly doped Nd:YAG rod contained within an unstable optical resonator of the type wherein power flows outward from the optical axis of the resonator. The output beam is coupled out of the resonator by means of a coupling device having a high coupling factor (>55% of the circulating power inside the optical resonator) and in a preferred embodiment the coupling factor is as high as 80-90%. The optical resonator is preferably a confocal resonator employing one concave mirror and one convex mirror. The convex mirror forms the output coupling device for providing a high degree of diffraction output coupling around the periphery of the output mirror. The output beam is collimated in the region of the output mirror. The curvatures of the two mirrors forming the optical resonator are dimensioned to take into account the positive focusing lens effect of the high gain medium produced by a transverse thermal gradient in the high gain medium encountered in use when pumped by flash lamps. The laser is Q-switched by means of a linear polarizer and a pulsed KD*P quarter wave plate. The output beam has 25 megawatts of peak power with a pulse width of 10 nanoseconds, a pulse repetition rate of 10 pulses per second. The output beam has a power density of 75 megawatts per square centimeter.
摘要:
A tunable source of infrared radiation is obtained by irradiating an assemblage of Raman active gaseous atoms or molecules with a high intensity pumping beam of coherent radiation at a pump frequency .omega..sub.p to stimulate the generation of Stokes wave energy at a Stokes frequency .omega..sub.s and to stimulate the Raman resonant mode at the Raman mode frequency .omega..sub.R within the irradiated assemblage where the pump frequency .omega..sub.p minus the Stokes frequency .omega..sub.s is equal to the Raman mode frequency .omega..sub.R. The stimulated assemblage is irradiated with a tunable source of coherent radiation at a frequency .omega..sub.i to generate the output infrared radiation of the frequency .omega..sub.0 which is related to the Raman mode frequency .omega..sub.R and the input wave .omega..sub.i by the relation .omega..sub.0 =.omega..sub.i .+-..omega..sub.R. In one embodiment the interaction between the pump wave energy .omega..sub.p and the tunable input wave energy .omega..sub.i is collinear and the ratio of the phase velocity mismatch factor .DELTA.k to the electric field exponential gain coefficient T is within the range of 0.1 to 5. In another embodiment the pump wave energy .omega..sub.p and the tunable input wave energy .omega..sub.i have velocity vectors k.sub.p and k.sub.i which cross at an angle to each other to compensate for phase velocity mismatches in the medium. In another embodiment, the Stokes wave energy .omega..sub.s is generated by pump energy .omega..sub.p in a first Raman cell and .omega..sub.s, .omega..sub.i and .omega..sub.p are combined in a second Raman mixing cell to produce the output at .omega..sub.i.
摘要:
Systems, methods, devices and apparatus are implemented for producing controllable charged particle beams. In one implementation, an apparatus provides a deflection force to a charged particle beam. A source produces an electromagnetic wave. A structure, that is substantially transparent to the electromagnetic wave, includes a physical structure having a repeating pattern with a period L and a tilted angle α, relative to a direction of travel of the charged particle beam, the pattern affects the force of the electromagnetic wave upon the charged particle beam. A direction device introduces the electromagnetic wave to the structure to provide a phase-synchronous deflection force to the charged particle beam.
摘要:
Photodarkening in active fiber or waveguide devices (e.g. lasers, amplifiers, and incoherent sources such as ASE sources) can be reduced by altering the dopant concentration along the length of the doped fiber. A fiber or waveguide device includes two or more intentionally doped fiber or waveguide sections having different concentrations of one or more dopants. The dopants provide optical gain responsive to pump radiation provided to the fiber device by a pump source. A first optical intensity in a first of the fiber or waveguide sections is greater than a second optical intensity in a second of the fiber or waveguide sections. A first dopant concentration in the first fiber or waveguide section is lower than a second dopant concentration in the second fiber or waveguide section. Thus the dopant concentration is reduced in sections of the fiber or waveguide device having a higher optical intensity. The optical intensity can be due to pump radiation and/or signal radiation. Reduced dopant concentration in regions of high optical intensity reduces photodarkening.
摘要:
A monolithic crystalline material for quasi-phase-matching is described. The material includes a plurality of wafers of an odd multiple of coherence length thickness, having their faces bonded together by diffusion bonding. The wafers are oriented relative to one another to alternate their signs of nonlinear susceptibility. The invention also includes a method for producing optical radiation of a selected frequency by quasi-phase-matching, several specific methods and materials based on the discovery responsible for the invention, a generator for radiation of 60 THZ frequency of significant power, and a method of fabricating the material.
摘要:
A nonlinear waveguiding optical converter in a solid state body. The waveguide is provided with compositionally differing region (domains) of dominant electrical polarization in succeeding regions transverse to the path of guided radiation.
摘要:
A high power injection-locked laser system (10) is disclosed which includes master and slave lasers (12, 14) both of which are solid state lasers having continuous wave outputs. The slave laser has an output power at least ten times greater than the master laser. In the preferred embodiment, the slave laser is at least one-hundred times as powerful as the master laser. In accordance with the subject invention, a servo-loop control system is used to maintain the injection locked condition. A discriminant signal is generated that is indicative of drift in the slave laser cavity. The discriminant signal is used adjust the length of the slave laser cavity to maintain the locked condition.
摘要:
A moving slab laser includes a slab carriage driven to-and-fro along a precise rectilinear reciprocal path by a liner motor under the control of a computer. The reciprocal motion of the slab is precisely guided by cross roller ways or ball bushing bearings to minimize non-rectilinear motion-dependent output beam steering effects. In one embodiment, the lasant slab is separated into a pair of axially spaced geometrically identical portions which are reciprocated in opposite directions to cancel motion direction dependent beam steering effects.
摘要:
A stable high gain laser includes a Q switched multiple axial mode high gain oscillator, an oscillator for generating a stable optical wave at a first frequency, the first frequency being within the band of the multiple modes of operation, and a coupler for injecting the stable optical wave into the high gain oscillator whereby the axial mode nearest to the frequency of the injected wave selects a single axial mode and through gain saturation suppresses other modes of the high gain oscillator.