Wireless power transmitter

Abstract

To provide a distributed resonator laser system using spatially divided retro-reflective elements defining a power transmitting unit and a power receiving unit, respectively.SOLUTION: In a distributed cavity laser system using spatially divided retro-reflecting elements defining a power transmitting unit and a power receiving unit, respectively, the incident beam is reflected back along a path that essentially coincides with the path of the incident beam, since the retro-reflector has no reversal point; The optical system may advantageously be configured as a pupil imaging system by virtue of the fact that the distributed cavity laser may operate with the beam in a collinear mode rather than a ring mode, thereby allowing the inclusion of elements within the distributed cavity that have optical power, may act as focusing / defocusing, expand the field of view of the system, and change the Rayleigh length of the beam, and allowing optical components, e.g., a gain medium or a photoelectric converter, to be placed at such a pupil without physical limitation.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to the field of distributed laser cavities using retroreflectors, and in particular to intracavity lasers. It is used in a system that wirelessly transmits power to portable electronic devices using the output light. [Background technology]

[0002] PCT application PCT / IL2006 / 00 published as WO2007 / 036937 1131 "Directional optical transmitter and receiver" and WO / 2009 / 008399 Published PCT application PCT / IL2009 / 000010 entitled "Wireless Laser Output Light" In the paper, a wireless power delivery system based on a distributed laser cavity is presented. Used in the present disclosure to describe a laser with its resonator mirrors split into free space. There is no particular predetermined spatial relationship between the resonator mirrors, but they are randomly arranged. The laser can operate between the end reflectors. One use of fabric laser cavities is to place end mirrors in the transmitter and receiver. Therefore, optical power is transmitted from a centrally located transmitter to a mobile receiver located far from the transmitter. Such a distributed laser resonator has the following end mirrors: Simple retroreflectors such as corner cubes, cat's eyes and arrays thereof are used. Retroreflectors differ from plane mirror reflectors in that they have a non-infinitesimal field of view The electromagnetic wave front incident on the retroreflector within its field of view is parallel to the direction from the wave source, but The wave is reflected back along the opposite direction, even if the angle of incidence of such a wave on the retroreflector is Even if the reflection has a value different from zero, reflection still occurs. This is because the mirror is precisely aligned with the wavefront. A plane mirror reflector that reflects back along the incident path with zero angle of incidence only when perpendicular. are different.

[0003] Many of these commonly available retroreflectors are, for example, the retroreflector 15 shown in FIG. As shown in FIG. 1, the reflected beam 11 follows a spatially different path than the incident beam 12. By passing through, the inversion of the optical image is caused around the inversion point 10 located on the retroreflector (or , or in the case of an array of retroreflectors, around a number of points) or in close proximity thereto.

[0004] Inversion around this point creates several problems in practical systems.

[0005] In many such simple retroreflectors, the reversal point provides optical access. The light source is located in an optically opaque location that cannot be reached, such as a corner cube retroreflector.

[0006] b. Designed for practical use, as further described in paragraphs (c) through (f) below. Distributed laser systems require optical elements to be placed inside the resonator. , the reversal point at the optically opaque location results in two beams that do not overlap. Therefore, in addition to paragraph (a) above, this may be problematic. means that the retroreflector reverses the beam direction around the reversal point 10. Therefore, if the beam direction in cylindrical coordinates is expressed by the azimuth angle θ and the rest is constant, then R When becomes -R, the direction is reversed. For two beams, overlapping R is equal to -R. must be zero, which determines that R is equal to 0 and reflection occurs at the opaque inversion point. This non-overlapping results in the following: By placing a necessary optical element having at least one non-flat optical surface in the beam path, As a result, the two beams are generally non-parallel, and the distributed cavity lasing occurs. Such an optical component explains the behavior of two parallel beams. As shown in Figure 2, this can cause each beam to be refracted differently, with beam 1 being One labeled beam 2 passes through the optical center 21 of the lens 20, and the other labeled beam 3 passes through the center. It passes through the offset point 23. Of course, after passing through the lens 20, the beam is no longer Not parallel. For a distributed resonator to work, the two beams must remain parallel. Therefore, the above-mentioned WO2007 / 036937 and WO / 2009 / 008399 As shown, such an optical component inverts the optical image with its retroreflector and then projects it onto an opaque reflector. It cannot be used in a cavity with a turning point. It is possible to design various optical elements, such as the lens configuration of a telescope, may have a narrow field of view and limited functionality, and require fixed separation between the beams. This can cause aberrations in both beams. This has hindered the practical application of the solution proposed by GJ Linford et al. in U.S. Patent 4,209, Issue 689, "Secure Laser Communication Systems," describes a method for detecting laser beams emitted from a telescope near the gain medium of a resonator. A distributed laser resonator for long distance communication is described. handles beams confined to the axial direction, with as limited a field of view as possible, including propagation angles close to the axis The longitudinal position of elements downstream of the cavity length, e.g., the gain medium, is not described. The beam is not spread, and therefore the telescope uses it to limit the beam divergence and field of view. In many other cases, a telescope is not necessary, but rather serves a different function. Other optical elements, such as focusing lenses, may be needed, but due to the double beam, The same problem arises from

[0007] c. Optical system designed for two beams to accommodate the two beams and the distance between them requires the use of components that typically have diameters at least twice the size of an equivalent single-beam system. This increases the cost and overall width of the system.

[0008] d. To compensate for the Rayleigh expansion, the beam generally needs to be focused, so However, two simple retroreflectors are not sufficient to achieve laser oscillation. In / 2009 / 008399, this problem was solved by using a heat focusing element. However, such a solution adds complexity because it requires starting it. I am troubled by this.

[0009] e. An optical element having refractive power, for example an optical element having at least one non-planar surface, optical functions, such as achieving focusing, correcting aberrations, monitoring the system status, and To change the field of view or operate with different apertures to increase the performance / price of the system , it may be necessary to place it in the path of the beam. The two beams are essentially separated. Therefore, the aperture needs to be enlarged and it is difficult to block ghost beams. It may be difficult.

[0010] f. It is difficult to place imaging optics inside the resonator, so it is necessary to form an image of the receiver position. Such information may be difficult to obtain from a receiver or multiple devices connected to the transmitter. It may be necessary to monitor several receivers.

[0011] Since the direction and position of the beam in the system are unknown, the two PCT publications mentioned above Further problems arise in the distributed laser system shown in Figure 1 and the direction-sensitive components. Know where to place, for example, polarizers, wave plates, frequency doubling crystals, etc. in the beam path. It becomes difficult to use the detectors and gain media with limited space. The problem with knowing how to do this is that you don't know where to place these parts horizontally, It gets difficult.

[0012] Therefore, the present invention overcomes at least some of the above-mentioned drawbacks of conventional systems and methods. A fabric laser cavity architecture is needed.

[0013] The disclosure of each publication in this and other sections of the specification is incorporated herein by reference. The entire contents are incorporated herein by reference. Summary of the Invention

[0014] This disclosure describes a novel exemplary system for achieving distributed cavity laser operation using retroreflective elements. A system and method are described in which spatially separated retroreflective elements are used to transmit power to a power transmitting unit. One transmitter can be connected to several receivers with simple and easy configuration. The gain medium is advantageously located in the transmitter unit so that it can operate together with the transmitter. The described system and method adds a simple retroreflector to such a conventional laser oscillation system. The present invention also provides a method for solving the double beam problem associated with using a laser. solves the problem of determining both the lateral and longitudinal positions of various optical components within a laser cavity. This has a secondary effect on the laser oscillation characteristics of the resonator. This has the effect of enabling some or all of the features.

[0015] a) Allows retroreflection along the path of the incident beam, so that the incident and returning beams have the same path This characteristic makes the distributed laser different from the ring mode laser described in the prior art. It is possible to operate with beams in collinear mode rather than in coaxial mode.

[0016] b) An element with optical power, e.g., an element with one or more non-planar optical surfaces, is used as the exit / return beam. These components can be arranged in a modular system, where, among other things, Convergence / divergence Expanding the system's perspective Change the Rayleigh length of the beam Adaptation to particular working distances of the beam may be performed.

[0017] c) The parts can be positioned to ensure that the light always passes through the center of the part. This allows for areas within the system where components can be integrated to reduce size and cost and increase efficiency.

[0018] d) The optical components can be arranged to ensure that the light is always parallel to the optical axis. The system has an area where

[0019] e) Having an area in the system where an image of the receiver's position is formed and monitoring the receiver. This can be done.

[0020] f) A functional element that is highly sensitive to a laser beam but does not require laser oscillation operation itself. This allows for placement in areas where it is known that the laser beam cannot reach. The system has:

[0021] In order to achieve at least some of the above requirements, and thereby to It operates with the necessary functions and safety features for the practical application of such lasers in the environment. As will be explained shortly, this disclosure provides a distributed cavity laser that can A distributed laser with some novel features is proposed.

[0022] First, practical applications are based on retroreflectors that can reflect a beam back onto itself. The objective is to fabricate the end mirrors of the cavity using the same optics as the input and return beams from each retroreflector. Basically, the propagation paths are the same but opposite. In some examples of retroreflectors, the beam enters the cat's eye through the central region of its entrance aperture. Conventional cat-eye retroreflectors and converging / diverging cat-eye retroreflectors (one hemisphere) Two hemispheres, or multiple elements within them, that focus light onto the surface of the other hemisphere. (including complex structures with additional focusing) and multiple element (general purpose) cat's eye retroreflective a holographic retroreflector, a phase conjugate mirror, and reflecting a beam onto itself This includes reflective spherical mirrors, which can reflect light with a diverging beam as a result of reflection. This can be achieved by using focusing elements elsewhere along the beam path. This can be resolved.

[0023] However, such retroreflectors are prone to aberrations and other beam propagation problems, such as focusing. or divergence, excitation of higher-order beams, or other artifacts, which provides uniform quality laser radiation with acceptable power conversion efficiency and within generally accepted safety standards. In order to ensure the oscillation, it is necessary to process the This may limit the field of view, so it is not a practical system. Optical magnification may be required to fabricate the system. The stem components may not have the optimum, i.e., required, size or field of view. It can be corrected by using additional optics within the laser cavity. To overcome this and improve the overall laser system performance, the beam power in the resonator must be adjusted. It is necessary to add other optical components to the system that act to compensate for the undesired effects. It may be possible or advantageous to use a conventional distributed laser cavity with a double beam geometry. Therefore, inserting additional optical components into the beam is less effective due to this double beam geometry. However, this objective was now achieved by using a two-beam ring resonator instead of a conventional one. By using a single beam collinear resonator according to the disclosed exemplary resonator structure, It becomes possible.

[0024] Further intracavity optical components or subsystems may be used, and The objectives that can be achieved by using these are as follows:

[0025] (a) Using a telescope to expand the angular field of view of either the transmitter or receiver unit. It can be great.

[0026] (b) Using a telescope, the Rayleigh length of the system can be increased or decreased, thus This allows for an increase in the operating range (increasing the Rayleigh length) or a decrease in the operating range (reducing the Rayleigh length). (In this case) a single element can be selected from several elements within the range. .

[0027] (c) Using a focusing system in either the transmitter or receiver unit, The object can move from the transmitter to the receiver or to the receiver, and therefore This reduces the size of the beam at the receiver and therefore reduces the size of the receiver.

[0028] (d) Compensating for thermal lenses using lenses, grin lenses or curved mirror systems. or, for example, when using a ball mirror retroreflector, other undesirable effects in the system. The lens effect can be compensated for.

[0029] (e) Polarizers can be used to limit the polarization of light propagating within the laser oscillation system.

[0030] (f) Using a wave plate, (i) The polarization of the system can be limited.

[0031] (ii) a transparent object inserted into the beam and accidentally tilted at or near Brewster's angle Unintentional laser oscillation by the surface can be prevented.

[0032] (iii) Improvised and unauthorized use of receivers can be prevented.

[0033] (iv) The sensitivity of safety devices can be increased.

[0034] (g) Optical elements can be used to correct aberrations caused by various parts of the system. Cut.

[0035] (h) Use intracavity optics to amplify both forward and backward light. The gain medium can be made smaller, increasing gain and reducing size.

[0036] More details regarding some or all of these components are provided in the Detailed Description section below. do.

[0037] The presence of collinear counter-propagating beams makes it possible to treat such an optical component or subsystem as a laser. It can be placed in a resonator and achieve the objectives described in the previous paragraph. This is a major departure from conventional lasers, whether concentrated or distributed, where The imaging or focusing function is usually not integrated into the laser cavity. This can cause hot spots on the coating or on the component itself, or can lead to plasma generation within the resonator. It is usually undesirable to form a focal point within the laser cavity, as this can cause No other components are required inside the laser cavity other than those required for the lasing process itself. To minimize optical losses, simplify the system, and mitigate ghost beams, the resonator Attempts are usually made to avoid including such additional components within the In distributed laser cavities for applications of the type described in this disclosure, the transmitter and receiver units The dot can be placed anywhere within the environmental volume of the distributed laser cavity, and the laser , for a wide range of angles of incidence of the incoming and outgoing beams on each end mirror, with the desired efficiency. Since it must continue to operate, the wide angle angular steering of the end mirrors of the cavity and the gain medium is required. This is necessary to avoid damaging the laser oscillation process by allowing the laser to emit light from different angles of incidence. An intracavity optical subsystem is required to handle the light beam.

[0038] To facilitate these objectives, the exemplary distributed laser resonators described in this disclosure are The benefits of this approach are achieved through a novel design that involves the use of pupil imaging. The light coming from the incident angle and passing through the pupil forms an image on a given image plane, and the position of the image on this plane is determined by the angle of the pupil. It can be defined as the total light intensity from each different angle of incidence. All light, even though it is spatially spread, comes from a particular angle of incidence. All light from the image plane is transferred to the same spatial point on the image plane, provided that it passes through the pupil area. Light from different angles of incidence will produce different spatial points on the image plane. Therefore, the pupil itself is Based on these properties of the pupil imaging system, a definition can be given. A pictorial explanation of this concept is given below. This is done in Figure 3 in the Detailed Description section below.

[0039] The exemplary distributed cavity laser systems described in this disclosure are configured to have pupil imaging properties. This provides the following benefits to the system: The arrangement of optical components or subsystems within the laser system ensures a compact and easily designed laser system. This is also an important criterion for the optical imaging subsystem, as it requires the various components to be positioned in their optimum positions. Depending on the desired purpose, there are several different criteria that come into play. The system has an area, components are arranged in the area, and light from all angles of incidence is incident on those components. The design must ensure that the beam passes through the center of the product. The size of those components can be reduced, thus lowering costs and increasing efficiency This can be achieved with one pupil or multiple pupils of an imaging system with a pupil. Therefore, such a position or positions can cause such a component to lasing. Suitable for use as a gain medium, photovoltaic conversion detector, monitoring diode, etc. are.

[0040] In practice, a pupil imaging system is a focusing element, e.g., a lens, whose focal length is determined from the desired position of the pupil. The above definition of the behavior of a pupil-based imaging system is based on the fact that light is focused onto a lens. In terms of the Fourier transform between the angular and spatial information generated by passing through the lens, This can be easily explained using the Fourier transform method. A lens is a device that measures the distance that light travels through its focal length. This is explained by the mathematical Fourier transform of angles into positions. In a lens system, light emitted from the focal point of the lens at a certain angle to the optical axis is reflected by the lens. After passing through the lens, it moves a certain distance from the optical axis, which is a distance that depends on the angle, and then It is oriented parallel to the plane of the image, thus resolving all the angular information and converting it into fully spatial information. Spatial information can be reconverted into angular information by reversing the direction of light. The beam at the pupil of a single lens system does not have spatial information (the pupil point is predefined). Since the image is a 3D image, it only has angle information.

[0041] When the laser system is in operation, the laser beam is focused at the center of the front pupil of the transmitter and the center of the front pupil of the receiver. The beam is formed between the center of the front pupil and the transmitter. actually only has angular information passing through a known point. Then the transmitter optics The front pupil is imaged onto the internal pupil plane where the medium can be optimally positioned. The beam passes through the center of the receiving medium so that an accurate image of the front pupil of the system is formed at that location. Then, along the beam path, lenses placed at their focal distance from the internal pupil collect angular information. If there is no angle information, it is difficult to immediately place components that are sensitive to angle information. A telecentric region is formed.

[0042] Generally, throughout this application, the pupil effect refers to the amount of light passing through a beam when it enters a lens. by the actual pupil, as realized by the actual physical location in space This is achieved by projecting the image of the actual pupil onto another point in the system. References to pupils and pupils recited in the claims are understood to encompass both of these situations. It is intended to include.

[0043] By applying the definition of pupil imaging system from the above-mentioned distributed laser structure of this disclosure, The effect of the proximity is observed when a thin disk-shaped gain medium is used, which is placed in the image plane of the pupil imaging system. Light passing through the pupil from a certain direction always has a second magnitude relative to the telescope output after passing through the telescope system. This means that the beam is focused onto a disk of gain medium at the pupil of the The gain medium, whose thickness is significantly smaller than its lateral dimensions, is directed toward the transmitter through an entrance pupil. Laser oscillation occurs efficiently regardless of the direction of incidence of the laser beam. The stem is thus optimal if the retroreflector used in the system does not have a reversal point. In this case, the incident beam is reflected back colinearly from the retroreflector. This position of the gain medium relative to the elements of the imaging system is such that the imaging system is positioned at the input level of the transmitter containing the gain medium. This applies whether the imaging system is a lens or a retroreflector just before the gain medium is located. In either of these situations, the gain medium receives light from all incident directions within its field of view. is positioned relative to the imaging element so that it is focused onto the gain medium. Examples of how this can be accomplished are described in the detailed description section of this disclosure.

[0044] Furthermore, the system is designed so that the beams coming from different angles are parallel to each other in those regions (i.e. Other areas other than the pupil position that are optically directed through the The optical system must operate independently of the angle of incidence of the beam on the input lens. The substrate may be designed to have other areas where optical components can be placed.

[0045] Furthermore, the system is designed to have an area (image plane) in which an image of the field of view of the system can be formed. These areas must be designed to accommodate the placement of such optical subsystems. This is particularly useful for forming an image of the receiver's position, for example.

[0046] Furthermore, the system must be designed to have areas through which the laser beam does not pass. There must be a laser beam therein, where the part to be affected by the laser beam can be placed. Such components may monitor the level of such parameters, for example, as the gain medium fluorescence level. detectors that monitor the level of the pump diode beam, or directly in the gain medium. a pump beam sensor that monitors other wavelengths by their effect on their generation in the body; and It may also be a safety sensor. [Means for solving the problem]

[0047] One exemplary embodiment of the system described in this disclosure is a distributed cavity laser system. The distributed cavity laser system includes: (i) directing the beam incident on them along a path that essentially coincides with the path of the incident beam; first and second retroreflectors that reflect light in opposite directions; (ii) a gain medium disposed between the first and second retroreflectors; (iii) an output cap positioned to direct a portion of the beam impinging on it out of the resonator; With plastic, (iv) an output coupler so that the part of the beam directed out of the resonator strikes it; a beam absorbing component disposed relative to the (v) at least one optical element disposed between the retroreflectors and having at least one non-planar optical surface; and two optical components, the gain medium essentially having at least one non-planar optical surface. The optical system is disposed at the pupil of the optical system incorporating at least one optical component.

[0048] In the distributed cavity laser system described above, the beam absorbing component is a photovoltaic power converter or The at least one optical component may be either one of the heat conducting components. To define the entrance / exit pupils so that light passing through the lens at multiple different angles is directed toward the gain medium. Alternatively, the at least one optical element may be at least one lens arranged on the at least one optical element. The product defines an entrance / exit pupil so that light passing through the pupil at multiple different angles is directed toward the gain medium. It may also be a mirror positioned to

[0049] Furthermore, in accordance with an exemplary embodiment, such a system may include a refracting beam. The lens may further include a second lens arranged such that the center and the This creates a region of propagation parallel to the axis connecting the two media.

[0050] Furthermore, at least one optical component having at least one non-planar optical surface is The gain medium may be part of an optical system having an entrance / exit pupil imaged It can be placed in the eyes.

[0051] In any of the exemplary distributed cavity laser systems described above, the first and second retroreflectors At least one of the reflectors must not have an inversion point. Furthermore, the optical system must be such that at least It must have one image plane and at least one telecentric area. It may be possible.

[0052] Additionally, the distributed cavity laser system may further include a sensor located at the pupil. The output coupler may be part of one of the retroreflectors, or it may be a It may be independent of the reflector.

[0053] Additionally, other embodiments of the distributed cavity laser systems described in this disclosure include: (i) A beam incident on it is directed along a path that essentially coincides with the path of the incident beam. a first retroreflector that reflects in the opposite direction; (ii) directing the beam incident on it along a path essentially coinciding with the path of the incident beam; a second retroreflector that reflects light in the opposite direction; (iii) a gain medium disposed between the first and second retroreflectors; (iv) the gain medium is disposed at the image plane between the first and second retroreflectors; and a lens system positioned so as to

[0054] In such a system, a lens system is disposed at the opposite end of the gain medium. The optical system further has an external pupil plane defined by a gain medium at an internal pupil plane, and light passing through the external pupil from any direction is incident on the gain medium at an internal pupil plane. In any of these systems, the system has at least one It may also include a telecentric region. In this case, it may include a photosensor that forms an electronic image on the imaging plane. Further components that can be incorporated into the system include a telecentric region. The optical system may further include a polarizer, a multiplying optic, or one or more wave plates located in the optical region to manipulate the light components. The system may further include a sensor located at the pupil. [Brief explanation of the drawings]

[0055] The presently claimed invention will be more fully understood from the following detailed description taken in conjunction with the drawings. [Figure 1] FIG. 1 shows a typical conventional cube corner retroreflector in which the reflected beam traverses a spatially different path than the incident beam, thereby causing optical image inversion around a point located on the retroreflector. [Figure 2] 2A-2C are schematic diagrams illustrating the results of placing a lens in the beam path of a retroreflector, such as that shown in FIG. 1, having an optical reversal point, resulting in spatially separated propagating beams. [Figure 3] FIG. 1 illustrates how the pupil, i.e., pupil plane and pupil imaging, can be visualized as used in the present disclosure. [Figure 4A] FIG. 1 shows a schematic diagram of a cat's eye retroreflector that can retroreflect a beam passing through its reversal point. [Figure 4B]FIG. 1 is a diagram illustrating a telecentric retroreflector using a flat reflecting mirror. [Figure 5] FIG. 1 is a schematic diagram of a small spherical reflecting mirror that retroreflects a beam toward the center of the sphere. [Figure 6] 1 is a schematic diagram of a distributed laser system according to one exemplary embodiment of novel structural features described in this disclosure, illustrating the location of the system's pupil. [Figure 7] 7 shows a schematic representation of the distributed laser system of FIG. 6, including details of its components, illustrating further components of the laser oscillation system. [Figure 8] FIG. 10 shows a representation of a beam profiling unit that determines the presence of any perturbations to the propagating beam shape. [Figure 9] FIG. 10 illustrates how an auxiliary lens can be used to create a telecentric region in the system. [Figure 10] FIG. 8 is a diagram illustrating a schematic of how several pupils can be incorporated into the pupil imaging system shown in FIGS. [Figure 11] FIG. 10 shows a schematic diagram of the use of beam inaccessible areas for various monitoring functions. [Figure 12] FIG. 10 is a diagram illustrating the use of mirror focusing of the transmitter instead of the lens focusing described above. DETAILED DESCRIPTION OF THE INVENTION

[0056] First, referring to FIG. 3, FIG. 3 is a block diagram of the device described in the Summary of the Invention section of this disclosure. To clarify these explanations visually, let us visualize the pupil, i.e., the pupil plane and pupil image formation. In FIG. 3, the lens 24 is positioned in space. All parallel beams passing through 25 form image points on the image plane 26. For example, parallel beams 27 will be focused to a point 27a on the image plane, while the parallel beam 28 will This will form a focused image point 28a on 26.

[0057] The system is designed or configured to handle non-collimated beams with a specific radius of curvature. If the image plane moves through space, it can still exist. In this application, the beam width is basically the same as or The area near the pupil, which has a significantly larger width, is called the "pupil," and the surface where the beam converges is called the "eyepiece." A telescope generally has an entrance pupil and an exit pupil, and the light passing through the entrance pupil is called an "image plane." The light beam can also pass through the exit pupil. Two pupils are used, one pupil is optically aligned with the other pupil. It is placed in space as if it were a statue.

[0058] Referring now to FIG. 4A, FIG. 4A shows the structure of a conventional cat's eye retroreflector 30. The cat's eye retroreflector 30 is shown in FIG. 4A, and the beam is reflected by the lens 32. The beam is then recursively reflected back along its incident path, provided that it passes through the reversal point 31 at the center. In such a retroreflector, the concave mirror 33 is positioned at the entrance lens 3 2, precisely at the focal distance from the entrance lens 32, and The beam incident on each of the incident lenses 32 is focused onto the mirror surface of the concave mirror 33. Elevation beams are focused at different spatial locations on the mirror surface. Explain the importance of the reversal point. To do this, two incident beams are shown in Figure 4A. Beam 35 coming from the region in the upper left of the drawing is The light passes through the reversal point 31 at the center of the lens 33 and strikes the reflecting mirror 33 at a perpendicular angle of incidence. On the other hand, the beam coming from the bottom left of the drawing The mirror 36 passes through the lens 32 at a position away from the reversal point 31 and is mirrored at a non-zero angle of incidence. The light strikes the target 33 and is reflected back down a path 37 that is parallel to but not coincident with the incident path. Rays passing through the central inversion point of the lens at any angle of incidence will be directed along their own paths. Since the light is retroreflected in the opposite direction, this position represents the pupil of the cat's eye optical system. However, the pupil is an ideal location for placing the gain medium of the laser cavity. Because it is located in the center of the lens, the use of this simple cat's eye retroreflector is limited, but Therefore, unless the gain medium also functions as a lens, e.g. Unless shaped or using thermal lensing properties caused by the gain medium during lasing Therefore, it is difficult to place a gain medium there.

[0059] Therefore, referring to FIG. 4B, FIG. 4B shows a configuration in which the pupil of the retroreflector of FIG. 4A is A telecentric retroreflector 40 is shown schematically, which solves the problem of non-alignment. The reflecting mirror is a plane mirror 43, and similar to FIG. 4A, the plane mirror 43 is 2 to the focal length. The pupil, shown as pupil region 44 in FIG. The focal length of the lens 42 is equal to the focal length of the input side of the lens 42. The light rays are usually focused to a position on the reflecting mirror based on their angle of incidence and centered on the pupil. The reflected light is reflected back along its incident path. 4A, the pupil plane is 47 is now physically outside the focusing lens and is an optical component, e.g., a gain medium or photoelectric conversion element. Transducer (if it is only partially absorbing), aperture or output to block ghost beams The coupler can be placed at such a pupil without any physical restrictions.

[0060] An alternative to the cat's eye type retroreflector mentioned above is a retroreflector that does not have a reversal point, yet still A retroreflector is a device that can retroreflect a beam by itself. An example of such a device is shown in Figure 5. As shown in the figure, the small spherical reflective mirror 50 is a spherical reflective mirror. As shown by the beam 52 incident perpendicularly on the mirror, the beam is directed towards the center 51 of the sphere. The spherical mirror is retroreflected and diverges, while the beam 53 is incident horizontally on the sphere. Beams not directed towards the center of the sphere are not retroreflected but are reflected off the sphere in some other direction. and dissipates in that manner.

[0061] Referring now to FIG. 6, FIG. 6 illustrates one of the novel structural features described in this disclosure. 1 shows a schematic diagram of a distributed laser system according to an exemplary embodiment of the present invention, e.g., It can be used to distribute power from a transmitting source to a remote receiver, which can be used to The power can be used to operate or charge the batteries of portable electronic devices One inherent feature of the optical design of such distributed laser systems is the need to reduce the lateral dimensions. A position within the system where components or elements of the laser oscillation system that must be installed can be advantageously located. , the pupil is positioned. Thus, for example, the gain medium is positioned at pupil 54, and 4 is a common pupil for the internal retroreflector 55 and for the internal end of the telescope 78, 8, pupil 54 functions as an internal pupil. Telescope 78 also has an external pupil on its outside. The external pupil is the exit / entrance pupil 57 of the transmitter, and the internal pupil is the pupil where the gain medium is located. The laser light from the exit / entrance transmitter pupil 57 is basically The beam propagates parallel to the center of the receiver entrance / exit pupil 58 and exits the receiver 59. The light between the two entrance / exit pupils (57, 58) is basically Since the two pupils 57 and 58 are parallel to each other, they are basically optically identical to each other. The receiver and transmitter can have optical components located there (due to the pupil imaging described above) as well. In that respect, each of the pupils of the system is essentially a separate pupil from the pupils of the other system. The telescope 78 shown in the embodiment of FIG. 6 generally includes a lens in its optical system. However, it is also possible to have a pupil at a desired position of the resonator and place a component, for example, a gain medium, there. It is understood that any other optical system that can be arranged may also be used. An exemplary system is shown in FIG. 12 below.

[0062] Referring now to FIG. 7, FIG. 7 shows details of the distributed laser system shown generally in FIG. The details are shown in the figure, which shows the details of the specific elements of the laser. The transmitter 60 includes a laser gain medium 61, a lens 63, and a rear mirror 62. Together they can retroreflect the laser beam back onto itself, e.g. form any kind of telecentric cat's eye retroreflector described in Body 61 may advantageously be a Nd:YAG lasing at 1064 nm. The receiver 65 is at the bottom of the drawing and includes an output coupler 66, which also The reflector must be part of a retroreflector that reflects the laser beam back onto itself. These three components, namely the rear retroreflector (including the lens 63 and the rear mirror 62), ), gain medium 61, and output coupler retroreflector (including output coupler 66 and lens 68). ) constitutes the basic laser oscillation system. Their relative position is a key element of the novelty of the presently described system. The beam propagates between two resonator mirrors 62 and 66 in free space 64, The internal cavity is a laser beam that delivers optical energy from the transmitter 60 to the receiver 65. As explained with respect to FIG. 6, the telescope 78 has two pupils, i.e., a gain medium. An internal pupil (relative to the transmitter) located at or very close to the body 61 and opposite the telescope 78 and an external (exit) pupil towards the free space propagation region 64 on the side. In addition to these pupils of the part, there are also internal pupils, i.e., This is the telecentric region of the telescope.

[0063] The transmitter rear mirror 62 in the exemplary embodiment shown in FIG. 7 is similar to that shown in FIG. 4B. 6. The gain medium includes a flat reflector located at the focal length of lens 63 in the same configuration shown in FIG. 61 is placed at the common pupil of the retroreflector and the internal pupil of the telescope 78, and The incident light is directed into the gain medium 61 and then reflected back to the retroreflector. A mirror 67 behind the gain medium 61 reflects the beam towards the rear retroreflector 62. , the beam passes through the gain medium 61 twice for each pass through the laser. However, the system The gain medium 61 may be formed without the mirror 67 and with the retroreflector 62. It is understood that a purely transparent configuration can be achieved by placing the can be.

[0064] The retroreflector of the receiver 65 in this embodiment is an output coupler 66, e.g., a partially reflecting mirror. and a lens 68 located at the focal length of the output coupler. That portion of the beam that passes through the reversal point in the center of the pupil, which is physically located at the center of the lens 68, It includes a cat's eye retroreflector that ensures that the light is reflected back along its incident path. The properties of the resonator are such that, if possible, the center of the beam passing through the pupil will produce efficient laser oscillation. beams pointing in other directions cannot produce laser oscillations and The center of the beam is developed using the other oriented portions of the beam. is the pupil of the receiver, and the receiver, as well as the transmitter, can see the incoming beam as long as it passes through the pupil. The output coupler 66 operates independently of the incident beam angle. , by another lens 69, onto a photovoltaic cell 70 which converts the optical power of the laser beam into electricity. This photovoltaic cell 70 is located at the other pupil, a focal distance away from the lens 69. The conventional distributed cavity laser has Photovoltaic cells with very large lateral dimensions that do not have the focusing capability enabled by this embodiment can be used. Need.

[0065] The above description is one possible example of components of an exemplary system of the type described in this disclosure. The transmitter may also be configured with several other special features beyond this configuration and the configuration shown in FIG. The transmitter 60 is located at the entrance / exit pupil 57 and is It may further include a beam blocking aperture 80 that blocks most of the reflected ghost beam. The elimination of such ghost reflections increases the security of the system. It may also have an entrance pupil 58 with a beam stop (not shown) for the same purpose. To transfer the position of the internal pupil to the surface of the external beam stop, a lens is attached to the entrance to the receiver. Furthermore, realizing such an image of the internal pupil is not achievable with many optical designs. It can be achieved.

[0066] The transmitter rear mirror 62 may be partially reflective and for monitoring purposes, the rear lead The beam splitter 71 is connected to the transmitter to allow the laser beam to pass through. A portion of the beam can be passed through to monitor the location of the receiver that causes the oscillation. This detector 72 may be in the form of a simple CCD camera, a quadrant photosensor or It can be any similar position detector. A simple algorithm is used for the position detection routine. By using the 1000-kV ... do.

[0067] Optionally, back leakage is performed to determine if there are any perturbations in the beam shape. Another part of the beam may be used to examine the beam profile. The leak beam is the Fourier transform of the beam shape at the pupil. To examine the file, a beam profiler 74 is positioned using a lens 75. This is necessary to create an image of the pupil on a surface that can be used to detect obstructions, such as the user's body part. This function is used as a safety feature to determine when a user enters the safe path. As long as the beam is not obstructed, the measured The resulting beam profile has a circular shape in most cases. When the beam enters the beam from a position, it is assumed that the output beam profile is The criticality of laser modes that can be destabilized by factors many times larger than the In the example shown in Figure 8, a small obstruction can cause significant degradation of the beam. The beam enters at a point to the side (determined by the orientation of the drawing), resulting in a distinct oval beam profile. A profile 77 is generated, which is immediately detected by the beam profiler 74. And for users who cause perturbations by entering the beam, To avoid potential damage, image processing algorithms are used to generate warnings or shutters. A shutdown signal can be generated in the laser system.

[0068] 7 may be used to expand the field of view of the transmitter 60. A polarizer may be placed in the telecentric region to limit the polarization of the light generated by the By limiting the polarization direction of the laser oscillation beam, On the other hand, laser oscillation occurs through a transparent surface that happens to have a Brewster angle, rather than intentionally. If the laser beam is unpolarized, the transparent surface will not Although the likelihood of insertion at an angle is low, it is still a present risk. However, in addition to the Brewster angle, the polarization direction of the beam becomes the Brewster angle, and the specified polarization If a transparent surface must be adjusted so that it can act as a reflector with The probability of accidental laser emission is very small, thereby increasing the safety of the system. Alternatively, a quarter wave plate can be added to the telecentric region of the transmitter or receiver to The beam polarization may be circular or unpolarized, thereby achieving an overall Brewster angle reflection. In another embodiment, each polarization direction directs the transmitter to one specific receiver. The polarization direction can be used to organize multiple special receivers so that they can be connected to the same receiver. .

[0069] A further focusing lens 79 is attached to the transmitter 6 to make a small compensating change to the Rayleigh length of the system. You can also enter 0.

[0070] Next, referring to FIG. 9, FIG. 9 shows how the telecentric region of the system is formed. This shows how a flat mirror cat's eye retroreflector can be used in a similar manner to the flat mirror cat's eye retroreflector shown in Figure 4B. In this method, when a lens 80 is located at its focal distance from the system pupil 81, the lens 80 refracts the beam in a direction parallel to the optical axis and on its path towards the image plane 82. The image plane 82 may be the rear plane mirror of a distributed laser cavity or any other plane mirror. The region where the beam propagates parallel to the optical axis is the telecentric region, where , any optical component whose performance depends on the direction of light passing through it can be placed The beam passing through the pupil at a different angle will be parallel and laterally shifted from the path shown in Figure 9. The beams are refracted into different paths, and the direction-sensitive component optically captures all of them in the same way. The configuration in Figure 9 shows the telecentric region as parallel to the optical axis, but the pupil is offset from its optical axis, the beam in the telecentric region tilted at different angles but still parallel to each other, they are detected by direction-sensitive optics. In the same way, such components are treated optically. multipliers, polarizers, wave plates of some kind, interference filters, or other laser systems It may even include additional associated lasing components.

[0071] Next, referring to FIG. 10, FIG. 10 shows some of the pupil imaging systems shown in FIGS. 6 and 7. The receivers Rx1 and Rx2 each have a front aperture The function of these pupils is to allow the incident beam from any direction The purpose is to ensure that the beam is directed towards the receiver's retroreflector. The aperture 103 is located at the entrance / exit pupil, and the light beam passing through the aperture 103 is desired from any outer angle. The light beam passes through the lens of the telescope 106. After that, it is focused onto the rear pupil of the telescope 106 where the gain medium 104 is located. The beam is emitted from the gain medium 104, passes through the telescope 106 and exits the transmitter Tx. The pupil position of the gain medium can also be determined by the position of the transmitter Tx. This diagram therefore shows the laser emission beam. shows how the light passes through several sequentially arranged pupils, and the pupils determine the behavior of the system. The beams propagating from the outside into the field of view at various angles intercept each of these components. a receiver or transmitter gain medium 104, a photodetector 70 and entrance / exit apertures 101, 102; 103 defines a surface that is focused onto an area of ​​small lateral dimensions suitable for placement as 103.

[0072] Referring now to FIG. 11, FIG. 11 shows a beam splitter for various monitoring functions. Such areas are already shown in Figs. 7 and 8. 8, where a portion of the back leak beam from the rear mirror 62 of the resonator is The beam shapes 76 and 77 are monitored using the detectors. Monitor the function of the laser emission beam even if it is not in the beam path or a selected part of it. There is an area where a beam detector, e.g. a photodiode, can be placed. For example, the gain medium can be probed and changes observed therein can lead to lasing. Such a location is shown diagrammatically in Figure 11, where: The various parts are given the same reference numerals as in FIG. 7. Thus, positions 111, 112, 11 3. High sensitivity detectors can be used without affecting the beam and without damaging the detector. Thus, for example, the fluorescence of the gain medium can be monitored without the need for a A detector that observes the power level of the emitted light at a wavelength different from the laser emission beam is used to measure the intensity of the light emitted from the object, e.g. Beam power variations resulting from obstruction of part of the external beam path by a part of the body Any changes can be detected immediately and the monitor signal can be used to detect the presence of an invaded body part. To avoid such damage, the laser can be shut off immediately. In practical applications, the detector can be used to measure the pump power, for example, when it is changed due to pump diode heating. A filter was installed to observe secondary laser emissions of different wavelengths from the gain medium that occur when the laser is converted. The monitor signal can be used to adjust the temperature or current of the pump diode. The thermal lens sensor is also positioned in this way to restore the correct laser oscillation state. It may be used.

[0073] All of the above-described embodiments of the system are illustrated using a lens to focus the laser beam. Next, referring to FIG. 12, FIG. 12 shows the arrangement of the lens elements for defining the entrance and exit pupils. 1 shows a schematic diagram of a distributed laser system using mirrors instead of lenses, and the pupil is divided into multiple different The light transmitted at various angles is directed towards the gain medium. The beam retroreflected by the receiver 121 is reflected by a telescope system including a pair of mirrors 123, 123. 125. Gain medium 125 is focused by a laser beam. 5 is optimally located at the pupil at the inner end of the double mirror telescope.

[0074] It will be understood by those skilled in the art that the present invention is not limited by what has been particularly shown in the drawings and described above. Rather, the scope of the present invention extends to the various features described above and modifications and variations thereof. It is understood that the above description includes all possible combinations and subcombinations of modifications and variations thereof, and that those skilled in the art will readily understand the above description. You will realize that this is not a modern technology.

Claims

1. Reflects an incident beam back along a path that essentially coincides with the path of the incident beam. first and second retroreflectors; a gain medium disposed between the first and second retroreflectors; an output coupler positioned to direct a portion of the beam impinging on it out of the resonator; La and to the output coupler so that the portion of the beam directed out of the resonator strikes the output coupler. a beam absorbing element arranged in such a manner that At least one optical element disposed between the retroreflectors and having at least one non-planar optical surface and an optical component of The gain medium essentially comprises at least one non-planar optical surface. A distributed cavity laser system located at the pupil of an optical system incorporating one optical component.

2. The beam absorbing component is either a photovoltaic power converter or a heat conducting component. Item 1. A distributed cavity laser system according to item 1.

3. The at least one optical component adjusts the gain of light passing through the pupil at a plurality of different angles. At least one lens positioned to define an entrance / exit pupil for the medium.

3. The distributed cavity laser system according to claim 1 or 2.

4. The at least one optical component adjusts the gain of light passing through the pupil at a plurality of different angles. Mirrors arranged to define entrance / exit pupils towards the medium.

2. The distributed cavity laser system according to claim 1 ,

5. and a second lens positioned to refract the beam, thereby 5. The method of claim 1, wherein the optical waveguide forms a region of propagation parallel to an axis connecting the center of the lens and the gain medium.

10. A distributed cavity laser system according to claim 1.

6. The at least one optical component having at least one non-planar optical surface has an image forming surface.

6. The distributed cavity laser system according to claim 1, which is part of an optical system for 。

7. 7. The optical system of claim 1, wherein the gain medium is located at an imaged pupil of the entrance / exit pupil.

3. A distributed cavity laser system according to claim 1.

8. 8. At least one of the first and second retroreflectors has no inversion point.

10. The distributed cavity laser system according to claim 1,

9. 9. The resonator of claim 1, wherein the resonator supports a collinear beam mode. Distributed cavity laser system.

10. 10. The optical system according to claim 1, wherein the optical system has at least one telecentric area.

10. A distributed cavity laser system according to claim 1.

11. 11. The optical system according to claim 1, wherein the optical system has at least one image plane. Distributed cavity laser system.

12. 12. The distributed resonator of claim 1, further comprising a sensor located at the pupil. Laser system.

13. 13. The method of claim 1, wherein the output coupler is part of one of the retroreflectors.

10. A distributed cavity laser system according to claim 1.

14. 13. The optical fiber according to claim 1, wherein the output coupler is separate from the retroreflector.

10. A distributed cavity laser system as described herein.

15. Reflects an incident beam back along a path that essentially coincides with the path of the incident beam. a first retroreflector; Reflects an incident beam back along a path that essentially coincides with the path of the incident beam. a second retroreflector; a gain medium disposed between the first and second retroreflectors; a position between the first and second retroreflectors such that the gain medium is located at a pupil; and a lens system disposed on the cavity surface.

16. The lens system further includes an external pupil plane disposed at an end thereof opposite that of the gain medium. and light passing through the external pupil from any direction is directed toward the center of the gain medium at the internal pupil plane.

16. The distributed cavity laser system of claim 15,

17. 17. The optical system according to claim 15, wherein the optical system has at least one telecentric region.

10. The distributed cavity laser system according to claim 1,

18. 18. The optical system according to claim 15, wherein the optical system has at least one image plane. The distributed cavity laser system shown.

19. 20. The distributed cavity laser of claim 18, further comprising a photosensor for forming an electronic image of said imaging plane. The System.

20. A polarizer, a multiplier, or one of the optical components located in the telecentric region for manipulating the optical components.

18. The distributed cavity laser system of claim 17, further comprising at least one of the above wave plates. Tem.

21. 21. The distributed resonance sensor according to any one of claims 15 to 20, further comprising a sensor located at the pupil. Instrument laser system.

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