Light particle or wave?
May 20th 2007 03:31
Light is made up of particles and hence inherently "grainy"; quantum optics is the study of the nature and effects of this. The fundamental ideas of quantum optics, namely Albert Einstein's 1905 theory of the photoelectric effect and all the understanding of the interaction between light and matter following from it not only form the basis of quantum optics but also were crucial for the development of quantum mechanics as a whole. However, the subfields of quantum mechanics dealing with matter-light interaction were principally regarded as research in matter rather than in light and hence, one rather spoke of atom physics and quantum electronics.
This changed with the invention of the laser in 1950. Laser science—i.e., research into principles, design and application of these devices—became an important field, and the quantum mechanics underlying the laser's principles was studied now with more emphasis on the properties of light, and the name quantum optics became customary.
As laser science needed good theoretical foundations, and also because research into these soon proved very fruitful, interest in quantum optics rose. A clearer understanding of the statistics of light was gained, with the introduction of the concepts of coherent states, squeezed light etc. being the successes of the 1970s and 1980s, as well as the development of short and ultrashort laser pulses created by Q switching and modelocking techniques, opening the way to the study of unimaginably fast ("ultrafast") processes. Applications for solid state research (e.g. Raman spectroscopy) were found, and mechanical forces of light on matter were studied. The latter led to levitating and positioning clouds of atoms or even small biological samples in an optical trap or optical tweezers by laser beam. This, along with Doppler cooling was the crucial technology needed to achieve the celebrated Bose-Einstein condensation.
Other remarkable results are the demonstration of quantum entanglement, quantum teleportation and (recently, in 2004) quantum logic gates. The latter are of much interest in quantum information theory, a subject which partly emerged from quantum optics, partly from theoretical computer science.
Posted by Virtual Library
This changed with the invention of the laser in 1950. Laser science—i.e., research into principles, design and application of these devices—became an important field, and the quantum mechanics underlying the laser's principles was studied now with more emphasis on the properties of light, and the name quantum optics became customary.
As laser science needed good theoretical foundations, and also because research into these soon proved very fruitful, interest in quantum optics rose. A clearer understanding of the statistics of light was gained, with the introduction of the concepts of coherent states, squeezed light etc. being the successes of the 1970s and 1980s, as well as the development of short and ultrashort laser pulses created by Q switching and modelocking techniques, opening the way to the study of unimaginably fast ("ultrafast") processes. Applications for solid state research (e.g. Raman spectroscopy) were found, and mechanical forces of light on matter were studied. The latter led to levitating and positioning clouds of atoms or even small biological samples in an optical trap or optical tweezers by laser beam. This, along with Doppler cooling was the crucial technology needed to achieve the celebrated Bose-Einstein condensation.
Other remarkable results are the demonstration of quantum entanglement, quantum teleportation and (recently, in 2004) quantum logic gates. The latter are of much interest in quantum information theory, a subject which partly emerged from quantum optics, partly from theoretical computer science.
Posted by Virtual Library
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