Готові списки джерел за темами / Optical phase conjugation

Добірка наукової літератури з теми "Optical phase conjugation"

Автор: Grafiati
Опубліковано: 4 червня 2021
Оновлено: 6 вересня 2023

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями

Оберіть тип джерела:

Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Optical phase conjugation".

Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.

Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.

Зміст

  1. Статті в журналах
  2. Дисертації
  3. Книги
  4. Частини книг
  5. Тези доповідей конференцій
  6. Звіти організацій

Статті в журналах з теми "Optical phase conjugation":

1

Damzen, M. J. "Optical Phase Conjugation." Optica Acta: International Journal of Optics 32, no. 6 (June 1985): 639. http://dx.doi.org/10.1080/716099688a.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Shkunov, Vladimir V., and Boris Ya Zel'dovich. "Optical Phase Conjugation." Scientific American 253, no. 6 (December 1985): 54–59. http://dx.doi.org/10.1038/scientificamerican1285-54.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Krolikowski, W., M. R. Belić, and A. Bledowski. "Phase transfer in optical phase conjugation." Physical Review A 37, no. 6 (March 1, 1988): 2224–26. http://dx.doi.org/10.1103/physreva.37.2224.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Ostermeyer, M., H. J. Kong, V. I. Kovalev, R. G. Harrison, A. A. Fotiadi, P. Mégret, M. Kalal, et al. "Trends in stimulated Brillouin scattering and optical phase conjugation." Laser and Particle Beams 26, no. 3 (June 9, 2008): 297–362. http://dx.doi.org/10.1017/s0263034608000335.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
AbstractAn overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report is based on the results of the “Second International Workshop on stimulated Brillouin scattering and phase conjugation” held in Potsdam/Germany in September 2007. The properties of stimulated Brillouin scattering are presented for the compensation of phase distortions in combination with novel laser technology like ceramics materials but also for e.g., phase stabilization, beam combination, and slow light. Photorefractive nonlinear mirrors and resonant refractive index gratings are addressed as phase conjugating mirrors in addition.
5

Chengmingyue Li, Chengmingyue Li. "Optical phase conjugation (OPC) for focusing light through/inside biological tissue." Infrared and Laser Engineering 48, no. 7 (2019): 702001. http://dx.doi.org/10.3788/irla201948.0702001.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Okada, Yoshiko, and Ichirou Yamaguchi. "Optical phase conjugation using bacteriorhodopsin." Optics & Laser Technology 24, no. 2 (April 1992): 104. http://dx.doi.org/10.1016/0030-3992(92)90043-2.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Moosad, K. P. B. "Optical phase conjugation for postgraduates." European Journal of Physics 10, no. 2 (April 1, 1989): 133–35. http://dx.doi.org/10.1088/0143-0807/10/2/011.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Pepper, David M. "Applications of Optical Phase Conjugation." Scientific American 254, no. 1 (January 1986): 74–83. http://dx.doi.org/10.1038/scientificamerican0186-74.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Eichmann, George, Yao Li, and R. R. Alfano. "Parallel optical logic using optical phase conjugation." Applied Optics 26, no. 2 (January 15, 1987): 194. http://dx.doi.org/10.1364/ao.26.000194.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Tang, Xuefeng, and Zongyan Wu. "WDM transmissions exploiting optical phase conjugation." Annales Des Télécommunications 62, no. 5-6 (May 2007): 518–30. http://dx.doi.org/10.1007/bf03253274.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Більше джерел
Також вас можуть зацікавити розширені добірки на тему "Optical phase conjugation" для конкретних типів джерел:
Статті в журналах Дисертації Книги

Дисертації з теми "Optical phase conjugation":

1

Schroeder, W. A. "Optical phase conjugation by stimulated Brillouin scattering." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46505.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Bor, Sheau-Shong. "Phase conjugation characteristics of Gaussian beam /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262825076392.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Anikeev, Igorʹ Yu. "Study of limiting factors and methods of optical phase conjugation by stimulated Brillouin scattering." Title page, table of contents and abstract only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09pha597.pdf.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
Includes bibliographical references (leaves 205-227) A study of phase conjugation by stimulated Brillouin scattering is presented with emphasis on the limiting factors, such as aperture and polarization losses, spatial coherence and saturation of the incident wave on the quality of phase conjugation, as well as the application of stimulated Brillouin scattering to loop phase-cojugated mirror and intracavity-SBS-cell-phase-conjugated oscillator.
4

HOLM, DAVID ALLEN. "QUANTUM THEORY OF MULTIWAVE MIXING (RESONANCE FLUORESCENCE, SATURATION SPECTROSCOPY, MODULATION, PHASE CONJUGATION, QUANTUM NOISE)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187980.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
This dissertation formulates and applies a theory describing how one or two strong classical waves and one or two weak quantum mechanical waves interact in a two-level medium. The theory unifies many topics in quantum optics, such as resonance fluorescence, saturation spectroscopy, modulation spectroscopy, the build up of laser and optical bistability instabilities, and phase conjugation. The theory is based on a quantum population pulsation approach that resembles the semiclassical theories, but is substantially more detailed. Calculations are performed to include the effects of inhomogeneous broadening, spatial hole burning, and Gaussian transverse variations. The resonance fluorescence spectrum in a high finesse optical cavity is analyzed in detail, demonstrating how stimulated emission and multiwave processes alter the spectrum from the usual three peaks. The effects of quantum noise during the propagation of weak signal and conjugate fields in phase conjugation and modulation spectroscopy are studied. Our analysis demonstrates that quantum noise affects not only the intensities of the signal and conjugate, but also their relative phase, and in particular we determine a quantum limit to the semiclassical theory of FM modulation spectroscopy. Finally, we derive the corresponding theory for the two-photon, two-level medium. This yields the first calculation of the two-photon resonance fluorescence spectrum. Because of the greater number of possible interactions in the two-photon two-level model, the theoretical formalism is considerably more complex, and many effects arise that are absent in the one-photon problem. We discuss the role of the Stark shifts on the emission spectrum and show how the Rayleigh scattering is markedly different.
5

Devrelis, Vladimyros. "Fidelity of optical phase conjugation using stimulated brillouin scattering /." Title page, contents and abstract only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phd514.pdf.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Ridley, Kevin Dennis. "Novel phase conjugation techniques based on stimulated Brillouin scattering." Thesis, Imperial College London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282087.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Kaczmarek, M. "Dynamics of resonant degenerate four-wave mixing and applications in gaseous media." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291286.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Smout, A. M. C. "Studies of novel photorefractive behaviour in self-pumped barium titanate." Thesis, University of Essex, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233022.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Lindsay, Iain. "Optical phase conjugation in photorefractive materials and its application to image processing." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47541.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Bach, Tobias. "Optical phase conjugation for laser beam clean-up with Sn₂P₂S₆ crystals /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17826.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Більше джерел

Книги з теми "Optical phase conjugation":

1

1946-, Gower M., and Proch D. 1941-, eds. Optical phase conjugation. Berlin: Springer, 1994.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Sakai, Junʼichi. Phase conjugate optics. New York: McGraw-Hill, 1992.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Zelʹdovich, B. I͡A. Principles of phase conjugation. Berlin: Springer-Verlag, 1985.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Dmitriev, V. G. Nelineĭnai͡a optika i obrashchenie volnovogo fronta. Moskva: Nauka. Fizmatlit, 2000.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Peřinová, Vlasta. Phase in optics. Singapore: World Scientific, 1998.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

1943-, Fisher Robert A., Abramowitz Ira, Society of Photo-optical Instrumentation Engineers., and University of Alabama in Huntsville. Center for Applied Optics., eds. Phase conjugation and beam combining and diagnostics: 14-16 January, 1987, Los Angeles, California. Bellingham, Wash: SPIE--the International Society for Optical Engineering, 1987.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Optics, European Congress on. Nonlinear optical materials: ECO1, 19-20 September 1988, Hamburg, Federal Republic of Germany. Edited by Roosen Gérald, European Physical Society, European Federation for Applied Optics., and Society of Photo-optical Instrumentation Engineers. Bellingham, Wash: SPIE, 1989.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
8

European Congress on Optics (3rd 1990 Hague, Netherlands). Nonlinear optical materials III: ECO3 : 14-15 March 1990, The Hague, The Netherlands. Edited by Günter Peter, European Physical Society, and Society of Photo-optical Instrumentation Engineers. Bellingham, Wash: SPIE, 1990.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Evans, Myron W. Optical phase conjugation in nuclear magnetic resonance: Laser NMR spectroscopy. Ithaca, N.Y: Cornell Theory Center, Cornell University, 1990.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Arnoldus, Henk F. Phase conjugation in a layer of nonlinear material. New York: Nova Science Publishers, 2005.

Знайти повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Більше джерел

Частини книг з теми "Optical phase conjugation":

1

Almeida, Silverio P., and Luis M. Bernardo. "Phase Conjugation Metrology." In Optical Metrology, 467–80. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3609-6_30.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Eichler, H. J., A. Haase, B. Liu, and O. Mehl. "Phase Conjugation Techniques." In Optical Resonators — Science and Engineering, 103–17. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-2486-9_7.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Dunning, G. J., and C. R. Giuliano. "Optical Computing Using Phase Conjugation." In Nonlinear Optics and Optical Computing, 173–95. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0629-0_12.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Schneider, Thomas. "Nonlinear Optical Phase Conjugation." In Nonlinear Optics in Telecommunications, 367–85. Berlin, Heidelberg: Springer Berlin Heidelberg, 2004. http://dx.doi.org/10.1007/978-3-662-08996-5_14.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Eason, Robert W. "Optical processing using phase conjugation." In Nonlinear Optics in Signal Processing, 190–228. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1560-5_6.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Zel’dovich, Boris Ya, Nikolai F. Pilipetsky, and Vladimir V. Shkunov. "Introduction to Optical Phase Conjugation." In Springer Series in Optical Sciences, 1–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-540-38959-0_1.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
7

Murti, YVGS, and C. Vijayan. "Optical Phase Conjugation and Bistability." In Essentials of Nonlinear Optics, 101–24. Chichester, UK: John Wiley & Sons, Ltd, 2014. http://dx.doi.org/10.1002/9781118902332.ch6.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
8

Murti, Y. V. G. S., and C. Vijayan. "Optical Phase Conjugation and Bistability." In Physics of Nonlinear Optics, 91–110. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-73979-9_6.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
9

Dunning, G. J., and C. R. Giuliano. "Selected References on Optical Computing Using Phase Conjugation." In Nonlinear Optics and Optical Computing, 265–68. Boston, MA: Springer US, 1990. http://dx.doi.org/10.1007/978-1-4613-0629-0_18.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Bigio, I. J., R. A. Fisher, T. R. Gosnell, N. A. Kurnit, T. R. Loree, T. R. Moore, A. V. Nowak, and D. E. Watkins. "New Developments in Optical Phase Conjugation." In Gas Flow and Chemical Lasers, 52–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-642-71859-5_8.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.

Тези доповідей конференцій з теми "Optical phase conjugation":

1

Tataronis, John, and Bahaa E. A. Saleh. "Phase conjugation of nonstationary optical signals." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.fw5.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
The generation of phase conjugated replicas of optical signals has been the subject of many theoretical and experimental studies. Phase conjugation of harmonic signals is a byproduct of certain nonlinear processes such as degenerate four- wave mixing and stimulated Brillouin scattering. Although conjugation of steady signals is well established, the possibility and the effectiveness of conjugating unsteady signals remain largely unexplored. When the envelope of an optical signal varies, new physical phenomena in the conjugation process arise. As previously shown,1 dispersion in the conjugation process distorts the phase conjugate replica of a pulsed signal. Distortion appears even if the response of the medium to the applied optical signal is instantaneous.
2

Yust, Brian G., Dhiraj K. Sardar, and Andrew Tsin. "Phase conjugating nanomirrors: utilizing optical phase conjugation for imaging." In SPIE BiOS, edited by Alexander N. Cartwright and Dan V. Nicolau. SPIE, 2011. http://dx.doi.org/10.1117/12.874293.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Hall, T. J. "Review Of Phase Conjugation." In Optical Systems for Space and Defence, edited by Alan H. Lettington. SPIE, 1990. http://dx.doi.org/10.1117/12.969673.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Zeldovich, B. Y. "Overview of optical phase conjugation." In Technical Digest Summaries of papers presented at the Conference on Lasers and Electro-Optics Conference Edition. 1998 Technical Digest Series, Vol.6. IEEE, 1998. http://dx.doi.org/10.1109/cleo.1998.676041.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
5

Rogovin, Daniel N. "Acoustically pumped optical phase conjugation." In OE/LASE '90, 14-19 Jan., Los Angeles, CA, edited by Robert A. Fisher and John F. Reintjes. SPIE, 1990. http://dx.doi.org/10.1117/12.18321.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
6

Shen, T. P., and D. Rogovin. "Optical phase conjugation in polyacetylene." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1991. http://dx.doi.org/10.1364/oam.1991.fg4.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
Polyacetylene is a long linear, chainlike material whose optical properties at visible wavelengths arise from the motion of the π-electrons along the bonds that connect the sites. The nonlinear optical properties of polyacetylene materialize from two anharmonic electronic interactions: (1) the π-electrons interact with the phonons and (2) they interact with each other through their Coulomb repulsion. The motion of the π-electrons driven by an optical field were described within a classical framework and the third-order optical susceptibility associated with phase conjugation was determined. The wavelength (λ) has dependence on the nonlinear optical susceptibility; two peaks coincide with a resonant response. A low frequency peak in the vicinity of 1.2 µm reflects a two-photon resonance process and arises from the Coulomb repulsion. A high frequency peak at 0.6 µm is the single photon resonance and arises from both the Coulomb repulsion and the electron phonon coupling.
7

Brody, Philip S., and Charles Garvin. "Microscope using optical phase conjugation." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/oam.1988.fy4.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
Phase contrast imaging by the backward passage of a phase-conjugate beam through a phase plate that was used to produce the original phase distorted beam depends on the phase conjugate of the original field passing back through the specimen after the specimen has been shifted. We demonstrated this previously using self-pumping in barium titanate to produce the phase-conjugate field and a mechanical means to shift the plate. The intensity images show the gradients of plate optical thickness with respect to the shift direction of the specimen’s optical thickness.1 We note that an image should also result if the slide remains stationary but component elements of the specimen move. Taking advantage of this last we have developed a microscope which shows dynamic processes within biological phase objects. The stationary elements on the slide do not show up; the image shows only those elements that move. The device includes a stage of digital processing which removes coherent artifacts and also adds gradients in intensity of moving elements in the bright field intensity image.
8

Little, Gordon R., and Steven C. Gustafson. "Binary pattern classification using optical phase conjugation." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/oam.1986.md3.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
Анотація:
An elementary binary pattern classifier has n binary input variables and one binary output variable. The input variables may be identified with image pixels so that there are 2n possible input patterns. Classification or specification of the binary output is required for m of these patterns; the remaining patterns are do not cares. For m > 2n and large n (e.g., n ≥ 64), classifiers using all-electronic combinatorial logic techniques generally require numerous decision elements and complex interconnections. These requirements may lead to limited performance in areas such as processing speed and noise tolerance. Classifiers based on holographic associative memory techniques and the use of optical phase conjugation have potential for providing substantial performance improvements in these areas. In particular, analytical and computer simulation results indicate that phase conjugation with thresholded gain may significantly impove the ability of holographic associative memory processors to correctly classify numerous noisy or highly cross-correlated binary patterns. This indication may be attributed mainly to the fact that an additional well-interconnected decision surface can be inserted in a classifier by a thresholded phase conjugator.
9

Khizhnyak, Anatoliy, and Vladimir Markov. "TIL system with nonlinear phase conjugation." In Optical Engineering + Applications, edited by Stephen M. Hammel, Alexander M. J. van Eijk, Michael T. Valley, and Mikhail A. Vorontsov. SPIE, 2007. http://dx.doi.org/10.1117/12.735161.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
10

Saavedra, G., Y. Sun, K. R. H. Bottrill, L. Galdino, F. Parmigiani, Z. Liu, D. J. Richardson, P. Petropoulos, R. I. Killey, and P. Bayvel. "Optical Phase Conjugation in Installed Optical Networks." In Optical Fiber Communication Conference. Washington, D.C.: OSA, 2018. http://dx.doi.org/10.1364/ofc.2018.w3e.2.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.

Звіти організацій з теми "Optical phase conjugation":

1

Bowers, M. W., C. Kecy, L. Little, J. Cooke, J. Benterou, R. Boyd, and T. Birks. Speckle Reduction for LIDAR Using Optical Phase Conjugation. Office of Scientific and Technical Information (OSTI), February 2001. http://dx.doi.org/10.2172/15013526.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
2

Richardson, Martin, and Magali Durand. Optical Phase Conjugation by Two Counter Propagating Filament. Fort Belvoir, VA: Defense Technical Information Center, February 2013. http://dx.doi.org/10.21236/ada581672.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
3

Hellwarth, Robert W. Optical Beam Phase-Conjugation and Electromagnetic Scattering Process with Intense Fields. Fort Belvoir, VA: Defense Technical Information Center, May 1988. http://dx.doi.org/10.21236/ada200372.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.
4

Marston, Philip L. Research on Acoustical Scattering, Diffraction Catastrophes, Optics of Bubbles, Photoacoustics, and Acoustical Phase Conjugation. Fort Belvoir, VA: Defense Technical Information Center, October 1986. http://dx.doi.org/10.21236/ada174401.

Повний текст джерела
Стилі APA, Harvard, Vancouver, ISO та ін.

До бібліографії