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Photorefractive materials and their applications II — Survey of applications
Book Reviews Introduction Function
to the Optical
C.S. Williams and O.A. Becklund Wiley Interscience, 1989, ISBN
Transfer
O-471-94770-9,
pp xi + 412, E33.35 This book covers the underlying principles, the definition, use and measurement of the Optical Transfer Function (OTF). The emphasis throughout is placed on the use of the OTF in optical system design, restricted to the optical components (that is, excluding the sampling of the system output by detectors). The book is divided into ten chapters and three appendices. The first chapter consists of a brief history of the subject and is followed by a chapter each devoted to definitions and to notational conventions. These foundation chapters are followed by a treatment of the contribution to the total wavefront aberration function made by spherical aberration, coma and astigmatism. The role of the OTF as a transfer function in a linear system is described in Chapter 5. Chapter 6 considers the procedure followed in lens design, describing the difficulty in specifying the performance of a lens system by a simple measure like resolution alone. Consideration is given to the role of the Modulation Transfer Function (MTF) and Phase Transfer Function (P’I’F) in the image appearance. In Chapter 7 the use of figures of merit related to Strehl ratios is examined and methods of balancing aberrations to achieve merit figures are considered. Chapter 8 is devoted to measurement of system performance by use of grating responses, edge and slit images and interferometric techniques. Chapter 9 is concerned with analytic prediction of the OTF error and subject to defocus of systems astigmatism. The final chapter is concerned with numerical methods for deducing the OTF from estimates of the system wavefront error. Finally, the three appendices are concerned with a review of some case history results, simple Fourier transform and convolution theory and scalar wave theory. The book contains many illustrations, mostly of high quality although some show signs of desk top publishing. Consideration is specifically restricted to the optical regime and effects like contrast reversal were not considered in applications such as high resolution electron microscopy, where they are quite important. On the first page the authors note ’ . there is evidence that a traditional dependence on geometrical optics and ray tracing for design and analysis has delayed acceptance of the OTF’. The dominant role of the MTF in this book, rather than the full OTF, illustrates the difficulty. Even in the final chapter the evaluation of the OTF from
initial data in the form of optical path differences observed in laboratory measurements or calculated from ray trace data’ is considered (my italics). This field suffers from the use of many synonyms and the authors use and explain a wide range of these, occasionally to the detriment of an easy-to-read text. In summary, a book likely to be very useful to those interested in actually using the OTF, but not one for browsing at leisure. Likely to be a useful addition to the libraries of any organization interested in optical system design. A. H. Green a wqv RSRE
Photorefractive Materials and their Applications II - Survey of Applications Edited by P. Gunter and J.-P. Huignard
Springer-Verlag, 1989, ISBN 3-540-19202-6, pp viii + 367, DM 124 The book is a collection of eight survey papers written by twenty-two of the leading experts in the field of photorefractive materials and non-linear optical phenomena, recruited from five different countries. In the introduction, the editors embark upon the task of focusing on the application of the physical phenomena manifested by and associated with the non-linear behaviour of the various photorefractive crystals. The topics covered by the book include image storage, information processing and non-linear wave mixing. Furthermore, the authors present, amongst other things, experimental results on parametric amplification, spatial light modulators, phase distortion compensation and wavefront restoration. Several outstanding results illustrate not only the possible application but also the limitations imposed by the material parameters of the crystal used in the experiment. In the second chapter ‘Application, Oscillation and Light-Induced Scattering in Photorefractive Crystals’ S.G. Odulov and MS. Soskin survey the subject of optical amplification of coherent light in photorefractive materials. The authors start off with the principles of light amplification due to the dynamic interaction between beams inside the photorefractive crystal. It is demonstrated that this dynamic hologram recorded in a non-linear medium can be utilized to develop a novel holographic amplifier, based on diffraction and light induced change in the refractive index. Optics
218
& Laser Technology Vol22 No 3 1990
Book Reviews Under steady-state conditions more than half of the intensity of the light beam incident on the sample is often transformed into scattered radiation. The authors therefore regarded it as an important task to deal with the light scattering and its implication in the process of light amplification. An account of polychromatic scattering is also given, suggesting a cone-type scattering. When positive feedback is incorporated in these optical amplifiers, self-excitation and oscillation can occur. The principles of these oscillators are described and various feasible configurations are outlined for optical amplifiers using photorefractive materials as active elements. Optical cavities with two-beam coupling, using one and two pump beams, are also discussed as well as ring cavities with BSO crystals. The third chapter ‘Photorefractive Effects in Waveguides’ by V.E. Wood, P.J. Cressman, R.L. Holman and C.M. Veber deals with techniques and methods by which waveguide photorefractivity can be studied and observed. of light using The history waveguides photorefractive materials, namely lithium niobate, started approximately two decades ago. Since then a large number of substances have been tried and a number of physical phenomena demonstrated within this field. The substances used as well as the experimental channel waveguides, based on photorefractivity, are tabulated with references to help the reader. The authors also draw the attention to recently discovered phenomena such as polarization conversion. The fourth chapter ‘Wave Propagation in Photorefractive Media’ by J.O. White, Sze-Keung Kwong, M. Cronin-Golomb, B. Fisher and A. Yariv is dedicated to the explanation of the role of the nonlinearity in the index of refraction in photorefractive crystals, by using coupled wave theory. Starting from a simple fixed grating, the authors lead the reader through the concept of dynamic reflection and transmission grating formation. The theory developed this way is then applied to the explanation of the operation of optical resonators with photorefractive gain. The two-wave mixing, formulated at the beginning, is extended to four wave interactions with third order non-linearity. Both the undepleted and depleted pump cases are considered. Self-pumped phase conjugate mirrors created a great deal of interest both as a new phenomenon and as a possible element for novel practical applications. Experimental results are given by the authors on applications such as wave distortion correction, end mirrors for laser resonators, ring gyroscopes and interferometers. In the fifth chapter ‘Phase-Conjugate Mirrors and Resonators with Photorefractive Materials’ the authors J. Feinberg and K.R. MacDonald review the application of the photorefractive materials for the purpose of phase (PCM) and self-pumped phase Optics Et Laser Technology Vol 22 No 3 1990
conjugation (SPPCM). After reviewing the formulation of two and four-wave mixing this chapter describes some of the applications of phase conjugate mirrors. The experimental findings on PCMs and SPPCMs are used to devise applications such as interferometry, photolithography, optical processing, image correlation, edge enhancement and associative memories. The sixth chapter ‘Optical Processing Using Wave Mixing in Photorefractive Crystals’ written by J.-P. Huignard and P. Gunter is a review of the work done on the application of photorefractive effects on optical signal processing. The authors dedicate in this chapter a great deal of effort to comparing substances kn0WI-l for their photorefractive properties. The main attributes by which the crystals can be selected from the available substances for one particular application are listed. The formulation of hologram formation in photorehactive crystals followed by descriptions of applications to signal processing such as imaging through a phase disturbing medium, real time interferometry and photolithography. The application list is complete with experimental results on image convolution and image edge enhancement. Photorefractive crystals permit the amplification of low intensity optical signals. This effect leads to practical application such as threshold detectors, optical logic circuits, image subtraction and associative memories. The seventh chapter, as its title indicates, ‘The Photorefractive Incoherent-To-Coherent Optical Converter’ by J.W. Yu, D. Psaltis, A. Manakchi, A.R. Tanguay and R.V. Johnson, is dedicated to one particular application of photorefractives, namely the incoherent-to-coherent optical conversion. After the description of the physical principles the authors describe the difference between the ideal, analytic model and its practical realization. It also describes the practical limitations at the recording and the reading out stage. In the appendix, expressions for the space charge field are given in both steady and full temporal evolution. Similar to the seventh chapter, the eighth, ‘Photorefractive Crystals in PRIZ Spatial Light Modulators’ by M.P. Petrov and A.V. Khomenko, also describes a single, but rather important, application in the field of optical modulators: namely SLMs. Optically addressed Spatial Light Modulators (SLMs) are essentially reversible photosensitive media used as input devices in real-time coherent optical processing systems. The authors describe the basic parameters, the recording process, its transfer function, linearity, noise and dynamic range. At the start, the editors set out to survey the practical application of photorefractive materials. In fact they not only achieved their goal but also provided a sound theoretical background, which leads the reader through the subject with relative ease. With the large amount of information
219
Book Reviews Infrared Optical Fibers
compiled in it, it could be a useful handbook for the researcher engaged in investigating photorefractive phenomena. It is however, just like any other in a rapidly changing and developing field, such as photorefractive effects, suffering from being out of date at the time of its publication. Most of the contributors however, realizing this danger, provided a more up-to-date list of publications.
T. Katsuyama and H. Matsumura Adam Hilger, 237.50, pp xii + 231
Lasers - The Success Story (The industry in the w J Perera Financial Times Business Information, 6:191 (UK), 220 I/ US$322 (overseas), pp 98
J Takacs University of Oxford
Optical Fiber Sensors (Proceedings International Conference, OFS ‘89)
of 6th
Edited by H.J. Arditty, J.P. Dakin and R.Th. Kersten Springer Verlag. DM 145.00, pp xvi + 576
Books received
Advances in Laser Science - IV (AIP Conference Proceedings No 191)
The following books have been received at the editorial office. Their inclusion in this column does not preclude publication of a review at a later date.
Editors J.L. Gale, D.F. Heller, M. Lapp and W.C. Stwalley American Institute of Physics, 6i65.00, pp xviii + 786
Practical Laser Safety (Second Edition, revised and expanded) D. C. Winburn Marcel Dekker, $59.75 (US/Canada), where), pp x + 241
Fundamentals of Laser Interactions II Edited by F. Ehlotzky Springer Verlag. DM 65.00, pp xi + 317
$7 1.50 (Else-
Coming Events Conferences
and exhibitions
1990
8-l
JUNE 25-26
3
34th annual international technical symposium on optical and optoelectronic applied science and engineering San Dlego, Cahfomia, USA
Third European Military Fiber Optics Conference (E-MFOC ‘90)
Munich, FRG Information Gatekeepers, Inc., 2 14 Harvard Avenue, Boston, Massachusetts 02 134. USA
Sub-Committee Chair, cJo Business Center for Academic Societies Japan, Conference Department, Crocevia Hongo 2F. 3-23- 1 Hongo, Bunkyo-ku, ‘Ibkyo 113, Japan
JULY
16-20
SPIE, PO Box 10. Bellmgham. Washington, 98227-00 10. USA 1 O-l 3
InterOpt
Eighth European Fiber Optic Communications and Local Area Networks Conference and Exposition (EFOWLAN ‘90)
‘90
Mumch, FRG Information Gatekeepers, Inc., 2 I4 Harvard Avenue, Boston, Massachusetts 02 134, USA
220
InterOpto ‘90 Secretariat, OITDA 20th Mon Burldmg. 7-4, Nishr- Sturnbashi 2-chome Minato-ku. Tokyo 105. Japan 16-20 11-l
3
Optoelectronics (OEC)
conference
Makuhan Messe. Chiba, japan Katsuyoshi Ito, OEC ‘90 Publicity and Registration
on
Lisbon, Portugal Prof Sevastiao Formosinho, Secretariat of ICL 90, Centro de Quimica Fisica Molecular, Universidade Tecnica de Lisboa, Insntuto Superior Tecruco, Av Rovisco Pais, 1096 Lisboa Codex, Portugal
?bkyo Japan
27-29
International conference luminescence
LEOWOSA conference
Nonlinear
optics
Kauaj, Hawaii LEOS, 445 Hoes Lane, Ptscataway, New Jersey 08854, USA
Optics Et Laser Technology Vol22 No 3 1990
to the Optical
C.S. Williams and O.A. Becklund Wiley Interscience, 1989, ISBN
Transfer
O-471-94770-9,
pp xi + 412, E33.35 This book covers the underlying principles, the definition, use and measurement of the Optical Transfer Function (OTF). The emphasis throughout is placed on the use of the OTF in optical system design, restricted to the optical components (that is, excluding the sampling of the system output by detectors). The book is divided into ten chapters and three appendices. The first chapter consists of a brief history of the subject and is followed by a chapter each devoted to definitions and to notational conventions. These foundation chapters are followed by a treatment of the contribution to the total wavefront aberration function made by spherical aberration, coma and astigmatism. The role of the OTF as a transfer function in a linear system is described in Chapter 5. Chapter 6 considers the procedure followed in lens design, describing the difficulty in specifying the performance of a lens system by a simple measure like resolution alone. Consideration is given to the role of the Modulation Transfer Function (MTF) and Phase Transfer Function (P’I’F) in the image appearance. In Chapter 7 the use of figures of merit related to Strehl ratios is examined and methods of balancing aberrations to achieve merit figures are considered. Chapter 8 is devoted to measurement of system performance by use of grating responses, edge and slit images and interferometric techniques. Chapter 9 is concerned with analytic prediction of the OTF error and subject to defocus of systems astigmatism. The final chapter is concerned with numerical methods for deducing the OTF from estimates of the system wavefront error. Finally, the three appendices are concerned with a review of some case history results, simple Fourier transform and convolution theory and scalar wave theory. The book contains many illustrations, mostly of high quality although some show signs of desk top publishing. Consideration is specifically restricted to the optical regime and effects like contrast reversal were not considered in applications such as high resolution electron microscopy, where they are quite important. On the first page the authors note ’ . there is evidence that a traditional dependence on geometrical optics and ray tracing for design and analysis has delayed acceptance of the OTF’. The dominant role of the MTF in this book, rather than the full OTF, illustrates the difficulty. Even in the final chapter the evaluation of the OTF from
initial data in the form of optical path differences observed in laboratory measurements or calculated from ray trace data’ is considered (my italics). This field suffers from the use of many synonyms and the authors use and explain a wide range of these, occasionally to the detriment of an easy-to-read text. In summary, a book likely to be very useful to those interested in actually using the OTF, but not one for browsing at leisure. Likely to be a useful addition to the libraries of any organization interested in optical system design. A. H. Green a wqv RSRE
Photorefractive Materials and their Applications II - Survey of Applications Edited by P. Gunter and J.-P. Huignard
Springer-Verlag, 1989, ISBN 3-540-19202-6, pp viii + 367, DM 124 The book is a collection of eight survey papers written by twenty-two of the leading experts in the field of photorefractive materials and non-linear optical phenomena, recruited from five different countries. In the introduction, the editors embark upon the task of focusing on the application of the physical phenomena manifested by and associated with the non-linear behaviour of the various photorefractive crystals. The topics covered by the book include image storage, information processing and non-linear wave mixing. Furthermore, the authors present, amongst other things, experimental results on parametric amplification, spatial light modulators, phase distortion compensation and wavefront restoration. Several outstanding results illustrate not only the possible application but also the limitations imposed by the material parameters of the crystal used in the experiment. In the second chapter ‘Application, Oscillation and Light-Induced Scattering in Photorefractive Crystals’ S.G. Odulov and MS. Soskin survey the subject of optical amplification of coherent light in photorefractive materials. The authors start off with the principles of light amplification due to the dynamic interaction between beams inside the photorefractive crystal. It is demonstrated that this dynamic hologram recorded in a non-linear medium can be utilized to develop a novel holographic amplifier, based on diffraction and light induced change in the refractive index. Optics
218
& Laser Technology Vol22 No 3 1990
Book Reviews Under steady-state conditions more than half of the intensity of the light beam incident on the sample is often transformed into scattered radiation. The authors therefore regarded it as an important task to deal with the light scattering and its implication in the process of light amplification. An account of polychromatic scattering is also given, suggesting a cone-type scattering. When positive feedback is incorporated in these optical amplifiers, self-excitation and oscillation can occur. The principles of these oscillators are described and various feasible configurations are outlined for optical amplifiers using photorefractive materials as active elements. Optical cavities with two-beam coupling, using one and two pump beams, are also discussed as well as ring cavities with BSO crystals. The third chapter ‘Photorefractive Effects in Waveguides’ by V.E. Wood, P.J. Cressman, R.L. Holman and C.M. Veber deals with techniques and methods by which waveguide photorefractivity can be studied and observed. of light using The history waveguides photorefractive materials, namely lithium niobate, started approximately two decades ago. Since then a large number of substances have been tried and a number of physical phenomena demonstrated within this field. The substances used as well as the experimental channel waveguides, based on photorefractivity, are tabulated with references to help the reader. The authors also draw the attention to recently discovered phenomena such as polarization conversion. The fourth chapter ‘Wave Propagation in Photorefractive Media’ by J.O. White, Sze-Keung Kwong, M. Cronin-Golomb, B. Fisher and A. Yariv is dedicated to the explanation of the role of the nonlinearity in the index of refraction in photorefractive crystals, by using coupled wave theory. Starting from a simple fixed grating, the authors lead the reader through the concept of dynamic reflection and transmission grating formation. The theory developed this way is then applied to the explanation of the operation of optical resonators with photorefractive gain. The two-wave mixing, formulated at the beginning, is extended to four wave interactions with third order non-linearity. Both the undepleted and depleted pump cases are considered. Self-pumped phase conjugate mirrors created a great deal of interest both as a new phenomenon and as a possible element for novel practical applications. Experimental results are given by the authors on applications such as wave distortion correction, end mirrors for laser resonators, ring gyroscopes and interferometers. In the fifth chapter ‘Phase-Conjugate Mirrors and Resonators with Photorefractive Materials’ the authors J. Feinberg and K.R. MacDonald review the application of the photorefractive materials for the purpose of phase (PCM) and self-pumped phase Optics Et Laser Technology Vol 22 No 3 1990
conjugation (SPPCM). After reviewing the formulation of two and four-wave mixing this chapter describes some of the applications of phase conjugate mirrors. The experimental findings on PCMs and SPPCMs are used to devise applications such as interferometry, photolithography, optical processing, image correlation, edge enhancement and associative memories. The sixth chapter ‘Optical Processing Using Wave Mixing in Photorefractive Crystals’ written by J.-P. Huignard and P. Gunter is a review of the work done on the application of photorefractive effects on optical signal processing. The authors dedicate in this chapter a great deal of effort to comparing substances kn0WI-l for their photorefractive properties. The main attributes by which the crystals can be selected from the available substances for one particular application are listed. The formulation of hologram formation in photorehactive crystals followed by descriptions of applications to signal processing such as imaging through a phase disturbing medium, real time interferometry and photolithography. The application list is complete with experimental results on image convolution and image edge enhancement. Photorefractive crystals permit the amplification of low intensity optical signals. This effect leads to practical application such as threshold detectors, optical logic circuits, image subtraction and associative memories. The seventh chapter, as its title indicates, ‘The Photorefractive Incoherent-To-Coherent Optical Converter’ by J.W. Yu, D. Psaltis, A. Manakchi, A.R. Tanguay and R.V. Johnson, is dedicated to one particular application of photorefractives, namely the incoherent-to-coherent optical conversion. After the description of the physical principles the authors describe the difference between the ideal, analytic model and its practical realization. It also describes the practical limitations at the recording and the reading out stage. In the appendix, expressions for the space charge field are given in both steady and full temporal evolution. Similar to the seventh chapter, the eighth, ‘Photorefractive Crystals in PRIZ Spatial Light Modulators’ by M.P. Petrov and A.V. Khomenko, also describes a single, but rather important, application in the field of optical modulators: namely SLMs. Optically addressed Spatial Light Modulators (SLMs) are essentially reversible photosensitive media used as input devices in real-time coherent optical processing systems. The authors describe the basic parameters, the recording process, its transfer function, linearity, noise and dynamic range. At the start, the editors set out to survey the practical application of photorefractive materials. In fact they not only achieved their goal but also provided a sound theoretical background, which leads the reader through the subject with relative ease. With the large amount of information
219
Book Reviews Infrared Optical Fibers
compiled in it, it could be a useful handbook for the researcher engaged in investigating photorefractive phenomena. It is however, just like any other in a rapidly changing and developing field, such as photorefractive effects, suffering from being out of date at the time of its publication. Most of the contributors however, realizing this danger, provided a more up-to-date list of publications.
T. Katsuyama and H. Matsumura Adam Hilger, 237.50, pp xii + 231
Lasers - The Success Story (The industry in the w J Perera Financial Times Business Information, 6:191 (UK), 220 I/ US$322 (overseas), pp 98
J Takacs University of Oxford
Optical Fiber Sensors (Proceedings International Conference, OFS ‘89)
of 6th
Edited by H.J. Arditty, J.P. Dakin and R.Th. Kersten Springer Verlag. DM 145.00, pp xvi + 576
Books received
Advances in Laser Science - IV (AIP Conference Proceedings No 191)
The following books have been received at the editorial office. Their inclusion in this column does not preclude publication of a review at a later date.
Editors J.L. Gale, D.F. Heller, M. Lapp and W.C. Stwalley American Institute of Physics, 6i65.00, pp xviii + 786
Practical Laser Safety (Second Edition, revised and expanded) D. C. Winburn Marcel Dekker, $59.75 (US/Canada), where), pp x + 241
Fundamentals of Laser Interactions II Edited by F. Ehlotzky Springer Verlag. DM 65.00, pp xi + 317
$7 1.50 (Else-
Coming Events Conferences
and exhibitions
1990
8-l
JUNE 25-26
3
34th annual international technical symposium on optical and optoelectronic applied science and engineering San Dlego, Cahfomia, USA
Third European Military Fiber Optics Conference (E-MFOC ‘90)
Munich, FRG Information Gatekeepers, Inc., 2 14 Harvard Avenue, Boston, Massachusetts 02 134. USA
Sub-Committee Chair, cJo Business Center for Academic Societies Japan, Conference Department, Crocevia Hongo 2F. 3-23- 1 Hongo, Bunkyo-ku, ‘Ibkyo 113, Japan
JULY
16-20
SPIE, PO Box 10. Bellmgham. Washington, 98227-00 10. USA 1 O-l 3
InterOpt
Eighth European Fiber Optic Communications and Local Area Networks Conference and Exposition (EFOWLAN ‘90)
‘90
Mumch, FRG Information Gatekeepers, Inc., 2 I4 Harvard Avenue, Boston, Massachusetts 02 134, USA
220
InterOpto ‘90 Secretariat, OITDA 20th Mon Burldmg. 7-4, Nishr- Sturnbashi 2-chome Minato-ku. Tokyo 105. Japan 16-20 11-l
3
Optoelectronics (OEC)
conference
Makuhan Messe. Chiba, japan Katsuyoshi Ito, OEC ‘90 Publicity and Registration
on
Lisbon, Portugal Prof Sevastiao Formosinho, Secretariat of ICL 90, Centro de Quimica Fisica Molecular, Universidade Tecnica de Lisboa, Insntuto Superior Tecruco, Av Rovisco Pais, 1096 Lisboa Codex, Portugal
?bkyo Japan
27-29
International conference luminescence
LEOWOSA conference
Nonlinear
optics
Kauaj, Hawaii LEOS, 445 Hoes Lane, Ptscataway, New Jersey 08854, USA
Optics Et Laser Technology Vol22 No 3 1990