The bandwidth of a batio 3 selfpumped phase conjugate mirror is measured in three different ways. An ideal phase conjugate mirror pcm reflects a light wave in which the wave vector and amplitude are reversed and are complex conjugated to the incident wave to create pcw 6,7. Osa phase conjugation through brillouinenhanced four. Multidirectional retroreflector assembly with a common. The earth is a nonlinear medium, and provides a very good phase conjugate mirror in the range of 0. Retroreflectors are used in various optical setups to return the incoming light parallel to the incoming beam, but with a lateral displacement. The bandwidth of a batio3 selfpumped phase conjugate mirror is measured in three different ways. Mungan, spring 2001 the eye of a cat can be modeled as a lens with a mirror at the focal plane. In the plane of the aperture stop there is an amplitudephase. In addition to corner reflectors, there are also cats eye reflectors and phase conjugate mirrors. Weak laser light reflected from a remote retroreflector was input to a highgain conjugate mirror. The resulting amplified output returns to the retroreflector owing to its phase conjugate nature. Either a phase conjugate mirror pcm or conventional mirror cm can be used to accomplish the.
Polarization change after propagation through a prism retroreflector output polarization of laser light measured after reflection from each sextant of a prism retroreflector. Evaluation of the returned electromagnetic signal from. Unlike an ordinary mirror, a retroreflector bounces an oncoming beam. Lasers at observatories on earth are aimed at retroreflectors planted on the moon during the apollo program 11, 14, and 15, and the two lunokhod missions. In addition to these three reflecting faces, there is a. Nonlinear optics nlo is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the polarization density p responds nonlinearly to the electric field e of the light. Mzthod of caicuiating retroreflectorarray trahisfer functions david a. The added phase is the key difference between a retroreflector and a phase conjugator fig. This page was last edited on 10 january 2019, at 00. Oct 07, 20 theyre everywhere in car taillights, traffic signs, and reflective tape on clothing. The physics of phase conjugate mirrors sciencedirect. To create the phase conjugate beam, the imaging beam with amplitude a 3 is first directed into a phase conjugate mirror fluid 55 cell. Jackel, inon moshe, and raphael lavi aberration correction in doublepass amplifiers through the use of phaseconjugate mirrors andor adaptive optics.
Electromagnetic equivalent model for phase conjugate mirror based on the utilization of lefthanded material guoan zheng1, lixin ran3, and changhuei yang1, 2 1department of electrical engineering, california institute of technology, pasadena, california 91125 2department of bioengineering, california institute of technology, pasadena, california 91125. Amplitude noise reduction of ion lasers with optical feedback. The physics of phase conjugate mirrors 5 basov et al. Electromagnetic equivalent model for phase conjugate. For the love of physics walter lewin may 16, 2011 duration. Theyre everywhere in car taillights, traffic signs, and reflective tape on clothing. A surface can be made partially retroreflective by depositing a layer of tiny refractive spheres on it or by creating small pyramid like structures. A phase conjugate mirror pcm has a remarkable property of cancellation the backscattering wave of the lossless scatterers. Aberration correction in doublepass amplifiers through the. Phase conjugate mirrors require a comparatively expensive and complex apparatus, as well. Both techniques allow an amplification of the conjugate wave compared to the incident wave. Electromagnetic equivalent model for phase conjugate mirror based on the utilization of lefthanded material guoan zheng1, lixin ran3, and changhuei yang1, 2 1department of electrical engineering, california institute of technology, pasadena, california 91125.
Pdf phaseconjugated directional diffraction from a. Retroreflector definition of retroreflector by merriam. The image produced is the inverse of one produced by a single mirror. The solution is based on a set of two coupled secondorder wave equations and does not assume the slowly varying envelope approximation. A third, much less common way of producing a retroreflector is to use the nonlinear optical phenomenon of phase conjugation. Electromagnetic equivalent model for phase conjugate mirror. The solution to the boundaryvalue problem for a simple model of the phase conjugate mirror is presented. Phase conjugated directional diffraction from a retroreflector array hologram. The double phase conjugate mirror dpcm is a selfpumped fourwave mixing geometry in which two mutually incoherent noncollinear pump beams intersect in a photorefractive nonlinear medium fig. Response of a batio 3 phase conjugate mirror to broadband. The pump 1 beam amplitude a 1 is also delayed and directed. A retroreflector sometimes called a retroflector or cataphote is a device or surface that reflects light back to its source with a minimum of scattering. This technique is used in advanced optical systems such as highpower lasers and optical transmission lines.
Phaseconjugate mirrors require a comparatively expensive and complex apparatus, as well. How retroreflectors measure the moon as a piece of common safety equipment, retroreflectors have saved countless lives. Directional properties of the ccr are due to the total internal reflection tir from its three orthogonally placed mirror surfaces, and have found. In a twodimensional retroreflector figure 2, is con structed through the vertex parallel to the incident ray and the reflected ray s.
Geri abstract conjugateoptical retroreflector cor display systems have the potential for providing inexpensive h ighresolution imagery aheadmounted display hmd conf uration. The principle of operation of this relatively straightforward boresight control system is extended to a higher order control phase conjugate system by using a retroreflector array, and a matching deformable mirror and wavefront sensor as shown in fig. A phaseconjugatemirror inspired approach for building. By using a hollow retroreflector, it is insensitive to the orientation of the four mirror retroreflector, i. Here, we present optical phase conjugationmirror with a one wave configuration for both input and phase conjugated beams fig. We show different schemes for realizing pcms and discuss characteristics such as reflectivity, fidelity, and time behavior. The resulting amplified output returns to the retroreflector owing to its phaseconjugate nature. Phase conjugate mirrors are used to provide optical feedback, thresholding, and gain. The most economic choice is a solid glass retroreflector, where the input and return beams travel through glass such as nbk7, but its applications are more limited. Optical devices such as retroreflectors scotchlite for example. In this paper we report on the application of phaseconjugate mirrors pcms for optical measurement techniques.
Overview our broadband hollow retroreflectors are constructed of three frontsurface mirrors assembled into a cornercube. Osa phase conjugation through brillouinenhanced fourwave. Optical measurements with phaseconjugate mirrors springerlink. By measuring both the angle through which the output beam is steered and the angle through which the output coupler is tuned it is found that the direction of propagation of the laser output is parallel to the normal to the mirror irrespective of the angle with the retroreflector. Both operate on similar principals, however with variations. Aberration correction in doublepass amplifiers through.
We propose and experimentally demonstrate naturally occurring phase conjugation by actively coupling arbitrary light fields into a singlemode. The similarity of a phase conjugate mirror to the interface of a matched rhm righthanded material and a lhm lefthanded material prompts us to explore the potentials of using the rhmlhm structure to achieve the antiscattering property of the pcm. The angle of incidence at which the device or surface reflects light in this way is. Unlike the picture of the aollo 11 array, this one has sunlight on its face, enabling a better view of the array of corner cubes. This is the main this is the main conceptbehindtherealtimeholography,betterknownasdegeneratefourwave. Using this system, laser trackers are used to probe locations inaccessible to the more conventional srms. Despite atmospheric effects the phaseconjugate return energy measured. A retroreflecting mirror was positioned one cavity length 170 cm from the output coupler of a largeframe cw arion laser that was operated in a single line 514 nm multilongitudinalmode configuration, i. Phaseconjugated directional diffraction from a retroreflector array. Pdf an optical adaptive resonance neural network utilizing.
Two scattered beams are generated that are counterpropagating to the pumps and are their phase conjugate replicas. As in time reversal, the wave reemitted by a phase conjugation mirror will autocompensate the phase distortion and autofocus itself on its initial source, which can be a moving object. Multidirectional retroreflector assembly a common virtual. Method for autoalignment of digital optical phase conjugation. There are a number of different studies of retroreflector arrays currently being done to assist in the design of future retroreflector arrays and obtain a better understanding of the properties of current retroreflector arrays. Lasers at observatories on earth are aimed at retroreflectors planted on the moon during the apollo program 11. Retroreflectors are used in transportation systems as unlighted nighttime. Response of a batio 3 phase conjugate mirror to broadband and. The retroreflector is used as a stable mirror in one arm. Broadband hollow retroreflectors newport corporation.
Megahertzrate shockwave distortion cancellation via. Phaseconjugated directional diffraction from a retroreflector array hologram. In the language of nonlinear optics, the interacting beams result in a nonlinear polarization within the material, which coherently radiates to form the phase conjugate wave. Despite atmospheric effects the phase conjugate return energy measured. The vertex of a retroreflector is balh7ay between the lines defined by the incident and the reflecte rays. The mirror causes incident light to be backreflected through the eye, thereby doubling its intensity inside the active layer and improving the cats night vision.
Pdf ray trace through a cornercube retroreflector with complex. The patented fabrication technique enables as fine as 1 arc second return beam parallelism with 3 wavefront distortion at an affordable price. Retroreflector definition is a device that reflects radiation such as light so that the paths of the reflected rays are parallel to those of the incident rays. Polarization change after propagation through a prism. We report what is to our knowledge the first demonstration of brillouinenhanced fourwave mixing over a long atmospheric path. Phase conjugation is an interesting wave phenomenon in which both the direction of propagation and the overall phase factor for each arbitrary plane wave component are precisely reversed during reflection from a phase conjugate mirror pcm 1, 2. Phaseconjugate mirrors on the basis of photorefractive crystals offer interesting possibilities of application for optical measurement systems. Our retroreflectors use the corner cube method to reflect a parallel return beam back from its source. All structured data from the file and property namespaces is available under the creative commons cc0 license. The nonlinearity is typically observed only at very high light intensities values of atomic electric fields, typically 10 8 vm such as those provided by lasers. In this paper we report on the application of phase conjugate mirrors pcms for optical measurement techniques. A preliminary study of a retroreflective mirror resonator.
Basic methods and algorithms the retroreflective property of a retroreflector results from three reflecting faces which are mutually perpendicular to each other. The ongoing lunar laser ranging experiment or apollo landing mirror measures the distance between surfaces of earth and the moon using laser ranging. Retroreflector definition of retroreflector by the free. Files are available under licenses specified on their description page.
The apparatus uses a shared aperture component to sample the outgoing laser beam and the incoming target beam, a retroreflector array to reverse the direction of the subaperture samples of the. Unlike an ordinary mirror, a retroreflector bounces an oncoming beam of light straight back to its source, no matter the angle. Practical nonlinear phase conjugators, however, add a constant phase. That is, the highly pressurized internal portions of the earth are already trembling, electro magnetically at those frequencies, but in scalar em resonance due to combined em waves and their phase conjugate replicas. He institute for lasers, photonics and biophotonics, state university of new york at buffalo. This is expected with phase conjugate resonators 8. Evaluation of the returned electromagnetic signal from retro. Papers phase conjugate optics and realtime holography core. These results suggest that a retroreflector is similar to an optical phase conjugate mirror, but with important differences. Our mrr mems device has the characteristic that it can be made to act as a normal plane mirror, or it can be deformed.
Apr 28, 2014 phase conjugate mirrors on the basis of photorefractive crystals offer interesting possibilities of application for optical measurement systems. The solution to the boundaryvalue problem for a simple model of the phaseconjugate mirror is presented. Comparison of a phase conjugate mirror with a conventional mirror. A process and apparatus are disclosed for aligning a laser beam from a laser transmitter with an incoming laser beam, and driving any sensed tilt differences on an aperture and subaperture basis to zero. Retroreflectors reflect incident light back toward the direction of the light source, operating over a wide range of angles of incidence. Typically they are constructed in one of two different forms, 90deg corner cubes or high indexofrefraction transparent spheres with a reflective backing.
While input beams normal to the base strike each face of the retroreflector at a roughly 55 angle of incidence 1, the s and p polarization components experience different phase delays and are split differently, depending on the order of surfaces they reflect from. Onewave optical phase conjugation mirror by actively. In a retroreflector an electromagnetic wavefront is reflected back along a vector that is parallel to but opposite in direction from the waves source. Phaseconjugate mirrors are used to provide optical feedback, thresholding, and gain. By using a hollow retroreflector, it is insensitive to the orientation of the fourmirror retroreflector, i. Soviet journal of quantum electronics nonlinear optical. Introduction the work described in this report was begun as part of the lageos study program formerly called cannonball supported by grant ngr 09015164 from the national aeronautics and space administration nasa. The key point to appreciate is that a conjugate mirror yields reflected wavefronts that are identical to those of the incident ones.
1190 1494 915 734 353 984 40 829 61 1477 280 1526 400 1249 316 987 1139 640 1499 1531 29 1520 104 771 1330 1429 132 387 1107 1393 302 369 1286 414 392