tailieunhanh - Nguyên tắc cơ bản của lượng tử ánh sáng P7

Conventional optical instruments make use of light that is transmitted between different locations in the form of beams that are collimated, relayed, focused, or scanned by mirrors, lenses, and prisms. Optical beams diffract and broaden, but they can be refocused by the use of lenses and mirrors. Although such beams are easily obstructed or scattered by various objects, this form of free-space transmission of light is the | Fundamentals of Photonics Bahaa E. A. Saleh Malvin Carl Teich Copyright 1991 John Wiley Sons Inc. ISBNs 0-471-83965-5 Hardback 0-471-2-1374-8 Electronic CHAPTER GUIDED-WAVE OPTICS PLANAR-MIRROR WAVEGUIDES PLANAR DIELECTRIC WAVEGUIDES A. Waveguide Modes B. Field Distributions C. Group Velocities TWO-DIMENSIONAL WAVEGUIDES OPTICAL COUPLING IN WAVEGUIDES A. Input Couplers B. Coupling Between Waveguides John Tyndall 1820-1893 was the first to demonstrate total internal reflection which is the basis of guided-wave optics. 238 Conventional optical instruments make use of light that is transmitted between different locations in the form of beams that are collimated relayed focused or scanned by mirrors lenses and prisms. Optical beams diffract and broaden but they can be refocused by the use of lenses and mirrors. Although such beams are easily obstructed or scattered by various objects this form of free-space transmission of light is the basis of most optical systems. There is however a relatively new technology for transmitting light through dielectric conduits guided-wave optics. It has been developed to provide long-distance light transmission without the use of relay lenses. Guided-wave optics has important applications in directing light to awkward places in establishing secure communications and in the fabrication of miniaturized optical and optoelectronic devices requiring the confinement of light. The basic concept of optical confinement is quite simple. A medium of one refractive index imbedded in a medium of lower refractive index acts as a light trap within which optical rays remain confined by multiple total internal reflections at the boundaries. Because this effect facilitates the confinement of light generated inside a medium of high refractive index see Exercise it can be exploited in making light conduits guides that transport light from one location to another. An optical waveguide is a light conduit consisting of a slab strip or .