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Fibre micro-interferometer
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Optical Preductien Technology D.F. Home
This is a revised edition of the original published nine years earlier which in turn was prepared as an update of the classical 1942 text On Prism and Lens making by F. Twyman. Inevitably this invites comparison. In weight the increase is from 1 Ib to 3½ ib with pages doubled in both size and number. More interesting is a large difference in style. Twyman wrote in a very personal way, often referring to his own many accomplishments, and mentioning personal friends corn plete with titles. Having been intimately involved with much of the work in his book, Twyman rarely included outside contributions. Home's style is quite different in that considerable portions of the book have been supplied by other authors whose depth of coverage varies from shallow to almost excessive. The personal style is absent,as in nearly all current books, to this reviewer's regret. Since both books cover quite well the gamut of optical production techniques of their time, a comparison provides a good insight into what new fields have grown important during the 40 years which intervene, and what within a field has changed. For examples, aspheres have gone from barely mentioned to important production, deserving no less than 10% of the new book, but describing all the important machining, polishing and even replication techniques. Also new is a chapter on electro-optics that includes a very brief mention of lasers, the remainder being devoted to optical techniques used in the cutting and polishing of electro-optic materials. Thin films occupy a crucial role in modern optics. They were quite new in Twyman's time, deserving less than six pages of an outside contribution in his book. Horne gives a superficial treatment of the theory and types of coatings and in keeping with the Published, price £45.00, by Adam Hilger Lt#, Techno House, Redcliffe Way, Bristol BS1 6NX, UK. ISBN 0-85274-350-5.
194
theme of the book concentrates on tools, vacuum techniques and glass cleaning. Sources given for equipment and special supplies will obviously help a newcomer to the field. The method for making chemical silver deposits is taken from Twyman, so that both authors leave the reader still wondering just why blank holding jigs must be soaked in stannous chloride solution before being used. In the manufacture of lenses and prisms a comparison between texts makes it clear that bonded diamond wheels have had a major impact on industry. Twyman only mentions diamond charged copper and cast Also relatively new are the Lapmaster type machine for efficient polishing of fiat surfaces, with its use of conditioning rings to maintain the flatness of the polisher. A lot of space is devoted to diamond wheel machinery for the edging of lenses, but the manufacture of the plated diamond wheels themselves is also well described. Basic grinding and polishing of glass has not changed much over the decades, except that cerium oxide has almost completely replaced rouge as the preferred polishing medium. Twyman barely even mentions it; as Horne points out, it triples polishing rates. Optical cementing is described in good detail and the treatment can be faulted only for not pointing out that Canada Balsam is not just an original material but is, in fact, no longer available. New in Home's text is a chapter on large telescope optics. This is interesting but in practice is the province of a small group of specialists. Another new chapter, of wider interest, covers dioptric (polarizing) substances, optical crystals as well as plastics. It also turns out to be home for an elementary discussion of cotour and lens imaging defects. Testing of optical elements has long been a basic part of the business
- nowhere else is there a better illustration of the old truism that you can make anything if you can test it. It occupies the largest single sections of both Twyman's and Horne's texts, and Horne has done a particularly good job here in assembling details of the many methods and instruments available. As with most chapters there is a good set of references, all combined at the end of the book. The book will be welcome news to almost all active in the field of optics. Manufacturers are likely to have greater personal knowledge in their own specialities but few would claim to have the insight to cover the whole field, as is done here. Users of optical elements will benefit from a better understanding of how they are made, although only a f e w are likely to appreciate a 20-page chapter on production planning, complete with route tickets. The layout of the book is excellent. Large type and good photographs make it easy to read, but inevitably make it bulky and heavy. Editorial work, proofreading,subject and author indexes are all well done. It will be a usefu I reference work for a large number of people. E.G. Loewen Rochester, NY, USA
Fibre micro-interferometer Using a miniature Michelson interferometer w i t h 'long distance' viewing optics, the F-IMt Fibre Micro Interferometer can measure cleave angles of both single and muttimode optical fibre end faces to an accuracy of better than 5 milliradians for a 125/~m diameter fibre. The fibre is placed in a precision alignment and clamp assembly and the end face is brought into focus; fringes provide a contour map of the fibre end surface. There is no risk of damage to the fibre sincethere is no physical contact with the end face. The instrument can also be used as a m~croscope to view the fibre end face directly. Newport Corporation, 18235 Mt Baldy Circle, Fountain Valley, CA 92708, USA
O C..,:'F" 1 9 8 3 V O L 5
NO4
Optical Preductien Technology D.F. Home
This is a revised edition of the original published nine years earlier which in turn was prepared as an update of the classical 1942 text On Prism and Lens making by F. Twyman. Inevitably this invites comparison. In weight the increase is from 1 Ib to 3½ ib with pages doubled in both size and number. More interesting is a large difference in style. Twyman wrote in a very personal way, often referring to his own many accomplishments, and mentioning personal friends corn plete with titles. Having been intimately involved with much of the work in his book, Twyman rarely included outside contributions. Home's style is quite different in that considerable portions of the book have been supplied by other authors whose depth of coverage varies from shallow to almost excessive. The personal style is absent,as in nearly all current books, to this reviewer's regret. Since both books cover quite well the gamut of optical production techniques of their time, a comparison provides a good insight into what new fields have grown important during the 40 years which intervene, and what within a field has changed. For examples, aspheres have gone from barely mentioned to important production, deserving no less than 10% of the new book, but describing all the important machining, polishing and even replication techniques. Also new is a chapter on electro-optics that includes a very brief mention of lasers, the remainder being devoted to optical techniques used in the cutting and polishing of electro-optic materials. Thin films occupy a crucial role in modern optics. They were quite new in Twyman's time, deserving less than six pages of an outside contribution in his book. Horne gives a superficial treatment of the theory and types of coatings and in keeping with the Published, price £45.00, by Adam Hilger Lt#, Techno House, Redcliffe Way, Bristol BS1 6NX, UK. ISBN 0-85274-350-5.
194
theme of the book concentrates on tools, vacuum techniques and glass cleaning. Sources given for equipment and special supplies will obviously help a newcomer to the field. The method for making chemical silver deposits is taken from Twyman, so that both authors leave the reader still wondering just why blank holding jigs must be soaked in stannous chloride solution before being used. In the manufacture of lenses and prisms a comparison between texts makes it clear that bonded diamond wheels have had a major impact on industry. Twyman only mentions diamond charged copper and cast Also relatively new are the Lapmaster type machine for efficient polishing of fiat surfaces, with its use of conditioning rings to maintain the flatness of the polisher. A lot of space is devoted to diamond wheel machinery for the edging of lenses, but the manufacture of the plated diamond wheels themselves is also well described. Basic grinding and polishing of glass has not changed much over the decades, except that cerium oxide has almost completely replaced rouge as the preferred polishing medium. Twyman barely even mentions it; as Horne points out, it triples polishing rates. Optical cementing is described in good detail and the treatment can be faulted only for not pointing out that Canada Balsam is not just an original material but is, in fact, no longer available. New in Home's text is a chapter on large telescope optics. This is interesting but in practice is the province of a small group of specialists. Another new chapter, of wider interest, covers dioptric (polarizing) substances, optical crystals as well as plastics. It also turns out to be home for an elementary discussion of cotour and lens imaging defects. Testing of optical elements has long been a basic part of the business
- nowhere else is there a better illustration of the old truism that you can make anything if you can test it. It occupies the largest single sections of both Twyman's and Horne's texts, and Horne has done a particularly good job here in assembling details of the many methods and instruments available. As with most chapters there is a good set of references, all combined at the end of the book. The book will be welcome news to almost all active in the field of optics. Manufacturers are likely to have greater personal knowledge in their own specialities but few would claim to have the insight to cover the whole field, as is done here. Users of optical elements will benefit from a better understanding of how they are made, although only a f e w are likely to appreciate a 20-page chapter on production planning, complete with route tickets. The layout of the book is excellent. Large type and good photographs make it easy to read, but inevitably make it bulky and heavy. Editorial work, proofreading,subject and author indexes are all well done. It will be a usefu I reference work for a large number of people. E.G. Loewen Rochester, NY, USA
Fibre micro-interferometer Using a miniature Michelson interferometer w i t h 'long distance' viewing optics, the F-IMt Fibre Micro Interferometer can measure cleave angles of both single and muttimode optical fibre end faces to an accuracy of better than 5 milliradians for a 125/~m diameter fibre. The fibre is placed in a precision alignment and clamp assembly and the end face is brought into focus; fringes provide a contour map of the fibre end surface. There is no risk of damage to the fibre sincethere is no physical contact with the end face. The instrument can also be used as a m~croscope to view the fibre end face directly. Newport Corporation, 18235 Mt Baldy Circle, Fountain Valley, CA 92708, USA
O C..,:'F" 1 9 8 3 V O L 5
NO4