Beam laser systems paul merritt pdf download

The system of claim 4 , further comprising: a second liquid crystal layer sandwiched between a third and a fourth substrate for fine tuning of the beam position. The system of claim 3 , further comprising: a PTR phase plate as a holographic material to provide a photosensitivity down to approximately zero spatial frequency for a stationary part of phase compensation, wherein the optically controlled liquid crystal modulator provides a variable part of phase compensation to create a tunable phase plate for aberration compensation and fine tuning of phase retardation in an optical system.

A method comprising the steps of: focusing a controlled laser beam on a liquid crystal layer sandwiched between a first and a second substrate;. The method of claim 8 , further comprising the step of: focusing the controlled beam on the liquid crystal layer with a lens. The method of claim 8 , further comprising the step of: controlling a power of the controlling beam to control a deflection angle of the e-component of the controlled beam.

The method of claim 8 , further comprising the step of: placing a collimator in the controlled beam after the controlled beam passes through the liquid crystal layer to adjust divergence of the controlled beam. The method of claim 11 , further comprising the step of: optical beam switching in optical connectors. The method of claim 11 , further comprising the step of: optical beam switching in multi-channel laser systems.

The method of claim 11 , further comprising the step of: optical beam switching in one of a beam scanner, pointer, and a target tracker. The method of claim 11 , further comprising: creating a tunable phase plate for aberration compensation or fine tuning of phase retardation in optical systems, wherein a stationary part of phase compensation is provided by a PTR phase plate which is feasible because this holographic material provides photosensitivity down to zero spatial frequency and a variable part of phase compensation is provided by means of the liquid crystal layer.

The method of claim 8 , further comprising the step of: modifying a distribution of power density across an aperture of the controlling beam to create an optical elements selected from a group comprising a prism array, lens, lens array, Fresnel prism, Fresnel lens, and a diffractive grating with variable period.

The method of claim 16 , further comprising the step of: using a Bragg grating recorded in a photosensitive PTR glass for angular magnification of the controlled beam for large angle beam deflection; and. The method of claim 16 , further comprising the step of: using one of an amplitude, a phase masks and a combination of at least two coherent beams to produce an interference pattern of having a preselected profile.

USP true Process for production of high efficiency volume diffractive elements in photo-thermo-refractive glass. Sensitization of photo-thermo-refractive glass to visible radiation by two-step illumination.

USA true Optical beam steering and switching by optically controlled liquid crystal spatial light modulator with angular magnification by high efficiency PTR Bragg gratings. USB1 en. Programmable fuse and anti-fuse elements and methods of changing conduction states of same. USB2 en. Aperture-sharing light beam two-dimensional positioning tracking method and device. Methods and apparatus for human vision correction using diffractive waveplate lenses.

Non-moving optical beam steering using non-pixelated liquid crystal optical phased arrays. Fabrication of high efficiency, high quality, large area diffractive waveplates and arrays. Optical arrangement and method for influencing the beam direction of at least one light beam. Broadband imaging with diffractive waveplate coated mirrors and diffractive waveplate objective lens.

Igor V. Paul F. Use of bragg grating elements for the conditioning of laser emission characteristics. Use of volume bragg gratings for the conditioning of laser emission characteristics. Use of Bragg grating elements for the conditioning of laser emission characteristics.

Use of volume Bragg gratings for the conditioning of laser emission characteristics. Diffractive waveplate lenses for correcting aberrations and polarization-independent functionality.

A kind of aperture light beam two-dimensional localization tracking and device altogether. USA en. KRA en. TWIB en. Stay et al. EPA2 en. Dominic et al. Measurement and modeling of the angular dispersion in liquid crystal broadband beam steering devices. The primary is a concave focusing mirror. As the secondary mirror's axial distance between it and the primary mirror is changed under control of the secondary, the telescope's focal length is adjustable.

This allows the real-time controller, either manually or under computer control, to focus the beam for maximum backfire setting effect on the target. Moving now to FIG. Assembly 50 is the power system which, as stated earlier, provides controlled electric power for all system assemblies and also for the electric-driven laser. The Waste Heat Control and Cooling Assembly 52 , maintains the desired temperatures throughout the system.

This electronic computer assembly uses pointing techniques that have matured mostly under military technology development. In the ABL program we perfected the technique for computer controlled autonomous target acquisition and tracking.

In the present embodiment, both Joy Stick and pre-planned computer autonomous track setting and GPS-assisted execution will be provided. Techniques for tracking the hot spot's path are similar to those we have developed for laser weapon systems. Completing the laser beam odyssey through the system module, the beam leaves the HEL 48 and enters the Beam Transfer Assembly This unit resizes the laser beam and cores it as needed to fit the requirements of the turret assembly.

The 46 is a storage space left to withdraw the turret assembly 42 when the laser is not in use in order to protect it from debris during flight. A bird strike protective cover, not shown, might also be used to close the aperture input. The operational concept for this first embodiment is as follows. Prior to the fire season, the helicopter is assumed to be outfitted at various times with differing modules for its many agriculture, power company, logging, and other tasks as has been done in the past.

Alternatively, the new laser backfire option may be used by a quick and straightforward replacement of the tank with the laser system module.

Hence it should arrive at the early stages of the fire in order to start setting a backfire downwind of the conflagration so as to remove possible fuel for the fire's spread. David Leigh and Zvika Avni Ref. They suggest a generic airborne laser to do this but no design information. In contrast, this patent provides example airborne laser systems that can serve this purpose.

In addition to the treetop backfires, more conventional ground level backfires may be set by the laser beam. As stated earlier, these backfires will be much quicker accomplished with the laser than by state-of-art non-laser system means. Finally, if after all the desired backfires are set, the craft can go into a infrared search mode for other hot spots or needed additional backfires. Alternatively it may return to base. To illustrate that in addition to helicopter designs, there are also fixed wing aircraft laser system module designs, we consider those aircraft here.

While those of us in the laser weapon system design field have considered pallet-loaded laser systems that could fit into large cargo aircraft like the Lockheed Martin CJ, the recent development of the previously discussed lightweight, smaller volume, higher efficiency and hence lower electric power and waste heat cooling requirements, RELI-class lasers makes the fixed wing fighter concept discussed here certainly possible.

Herlik U. In its militarized configuration shown, it is an incredible craft. Its overall length is One or two new fuel cells were placed in the nose, using some space that was previously occupied by the gun.

See also FIG. We also assume such modifications in FIG. Finally, we also assume the available envelope that Herlik used for his firefighting water tanks and pumps, but in our case for the laser module subsystem assemblies as seen in FIG. That envelope is about 4. The volume of this envelope is about 5.

Note that the U. And since our baseline RELI laser is being developed to have equivalent, or even lower volume and weight per unit output power, a 60 kW RELI system should find the available volume of 5. This laser system module seen in FIG. Note that the craft is outfitted, as was the helicopter, with , a Real-Time Fire Control Assembly which includes IR imaging, allowing it to let the pilot to see through smoke and also to operate at night.

Note that as with the first embodiment, the Turret needs to be stowed and its recess volume capped for protection whenever the craft is not setting backfires. This second embodiment has been described with reference to the A aircraft for illustrative purposes.

It is apparent to those skilled in the art of fighting fires from the air that different craft may be used without departing from the spirit and scope of this invention or the associated methods as claimed here.

These laser module systems may be attached to other craft to realize many of the same benefits. The purpose of showing the photos in FIG. After alerting the fire control group of the fire's location, the craft could then return quickly to base either for more retardant or, if desired, to make a quick exchange to convert to the laser system module which would allow it to fly out and begin backfire protection.

As previously stated, early backfire setting may drastically reduce the ultimate size of the conflagration and its loss of life and property and cost to extinguish. This laser system module-assisted fixed wing firefighter will operate much as the helicopter. Although it needs a runway unlike the helicopter, its cruise speed of mph would allow it to quickly get to the region where the backfire is to be set.

The laser system module aircraft will fight fires as follows. It will fly to a known fire's coordinates or locate the fire independently using its surveillance capabilities.

Of course these capabilities will allow it to identify and avoid flight hazards and to report such information to the fire controlling agency. Approval to begin setting backfires may be given along with the desired paths or a more free-lance approval given.

In either case the co-pilot fire manager aboard will enter the instructions into the laser beam pointing and tracking control system. Joy Stick operation or automatic operation will follow.

This backfire operation will continue until the desired path is completed. If the craft needs refueling it will return to refueling base and then quickly return to complete the backfire task.

If the gimbals are mounted on a moving or vibrating platform, these disturbances introduce additional tracking errors. Unlike target motion, this base motion disturbance can be directly measured using gyros and accelerometers, which are attached to the telescope.

The cartoon in Fig. However, the way it is shown, mounted on the telescope it would be sensitive to any vibration modes in the structure. One way to avoid this coupling could be to use an inertial reference unit IRU that includes a stable platform independent of the telescope structure. The HEL, shown simply in this cartoon as a box, provides the weapon beam to a pointing telescope, which is then mechanically boresighted optical axis made parallel to the tracking telescope.

As shown in the cartoon, the HEL is mounted on the telescope, most systems have the HEL mounted off the telescope and coupled into the telescope by a beam path that enters the telescope along the rotation axes.

Finally, the range to the target must be measured so that a parallax correction can be applied to the pointing telescope. This slightly tilts its optical axis to intersect the tracking telescopes optical axis at the range of the target and thus place the HEL beam on the aim point. The team was led by Dr. Whitney Co. An aerial view of the laser facility is shown as Fig. The laser device and the pointing and tracking system were in the building on the left of the figure.

The very basic pointing and tracking system are shown in Fig. The test series investigated tracking, pointing, focusing, thermal blooming, and atmospheric distortions with a slewing beam to a moving target. The row of large room fans seen in Fig. The gimbaled flat pointed the beam at a down-range target board that was mounted on an instrumented railroad car, known as the Everglazer, which could be moved while being tracked. This target board is shown in Fig.

This large and distributed laser test system was not something that could be mounted in a vehicle as a weapon, but the test series investigated an large number of critical laser system problems that would all be studied for years afterward. These included pointing, tracking, jitter control, higher order aberrations, adaptive optics, and beam diagnostics. This test introduced many of the later concepts of beam control, although the packaging of the system needed many changes to support an effective weapon.

It was a three-gimbal mount outer and inner azimuth plus elevation. The HEL beam entered the beam director from the bottom along the azimuth axis of rotation and was routed up and around one of the side arms with folding mirrors. It entered the telescope along the elevation axis of rotation and used a steering mirror to turn the beam and point it at the secondary mirror.

This beam director has been used for many purposes since and is still in service. It is shown in Fig. This system was the first demonstration of a coarse and fine gimbal to reduce line-of-sight jitter. It also used a gyro on the inner gimbals to inertially stabilize the pointing telescope.

Both beam directors were built by Hughes Aircraft in the mids and were similar in design. Optical Engineering. They both had four gimbals: coarse azimuth and elevation gimbals for large angular coverage plus fine azimuth and elevation gimbals that were inertially stabilized using gyros. They also both had tracking telescopes mounted to the inner gimbals but with their own line-of-sight optics. Figure 9 shows the ALL with both the forward and aft fairing installed.

The forward fairing was later removed and replaced with a much smaller fillet-like fairing. There were several experiments on the ALL that measured the aero-optical effects of the airflow around the turret and how it affected the propagation of the laser beam.

The APT introduced several beam-control concepts. Note the beam angle sensor in the lower section of the APT. Additionally, there is a translation sensor just past the aerodynamic window close to the laser device.

These sensors measured tilt and translation between the laser device and the base of the APT and used beam steering mirror 1 and 2 Fig.

Another alignment system controlled the beam from the base of the APT to the output beam expander. This system. This system sent a cylindrical beam around the outside of the HEL beam and measured the tilt through the beam path from the base to the output beam expander. The inertial reference was obtained by a gyro on the back of the primary mirror that used the inner gimbal and beam steering mirror 3, in the beam expander, to keep the outgoing beam inertially stable.

This system proved to be a problem area. The beam-expanding telescope had several vibration bending modes and the autoalignment reference annulus flexed so much that the autoalignment system did not adequately measure or control the jitter on the output beam. A fix for this was to replace the autoalignment annulus mirror with a flat annulus mirror mounted around the secondary mirror. This meant the alignment system no longer measured the motion of the primary mirror, but it permitted operation of the system through the final flight tests.

There were also test flights that removed the output window from the APT to see if the airflow around the turret would permit propagating a beam without using the window.

The result was that an acoustic mode existed in the open port, which significantly increased the jitter of the output beam. The output window was flown for the remaining flight tests. Figure 11 is a reversed photograph of the NPT. Merritt interrupted his civil service career in to work for Hughes Aircraft until and then rejoined the civil service until retirement in He then worked for Boeing-SVS for 6 years.

During this time Boeing developed an internal class on laser systems that included not only beam control but details on optical design and propagation. Upon retirement from Boeing the author developed a subset of the Boeing class and has taught a beam control class for the Directed Energy Professional Society for about 8 years. Starting in on an intermittent basis, Dr.

Merritt taught control theory classes at the University of New Mexico, and after retiring from Boeing taught control theory classes at UNM every semester for 6 years. One of the beautiful things about beam control is the breadth of the material. It can be very basic with a minimum of math or it can be very complex with new mathematical approaches and new systems to understand.