An intuitive picture of the physics underlying optical ranging using frequency shifted feedback lasers seeded by a phase-modulated field
Autor: | Klaas Bergmann, Leonid P. Yatsenko, Bruce W. Shore |
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Rok vydání: | 2009 |
Předmět: |
Physics
business.industry Phase (waves) Physics::Optics Ranging Laser Atomic and Molecular Physics and Optics Electronic Optical and Magnetic Materials law.invention Interferometry Amplitude Optics Orders of magnitude (time) law Electrical and Electronic Engineering Physical and Theoretical Chemistry business Frequency modulation Phase modulation |
Zdroj: | Optics Communications. 282:2212-2216 |
ISSN: | 0030-4018 |
Popis: | Frequency shifted feedback (FSF) lasers have been demonstrated to have interesting and useful features when used for optical ranging. The use of a phase-modulated seed to the FSF laser dramatically improves the signal-to-noise ratio, enabling distance measurements with the accuracy expected of optical interferometry. We present here an intuitively accessible description of the physics that underlies this dramatic enhancement of optical ranging signals. Unlike a free-running FSF laser, each one of the many equidistant frequency components of the seeded FSF laser spectrum (typically >104) has a definite amplitude, and a phase which varies with component number and modulation frequency Ω of the seed radiation. Suitable adjustment of Ω gives all components a common phase; the resulting constructive interference enhances the signal by orders of magnitude. |
Databáze: | OpenAIRE |
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