![]() ![]() In conjunction with transition cross-sections, intensities govern the rates of optical transitions, e.g.Optical intensities with the meaning as used in optical physics are relevant in various situations: The peak intensity can then vary, and may occur at locations at some distance from the beam axis. In a multimode laser beam, generated in a laser where higher-order transverse resonator modes are excited, the shape of the transverse intensity profile can undergo significant changes as the relative optical phases of the modes change with time. The equation can be verified by integrating the intensity over the whole beam area, which must result in the total power. Which is two times higher than is often assumed. It is sometimes called optical energy flux.įor a monochromatic propagating wave, such as a plane wave or a Gaussian beam, the local intensity is related to the amplitude of the electric field via The intensity is the product of photon energy and photon flux. ![]() The units of the optical intensity (or light intensity) are W/m 2 or (more commonly) W/cm 2. of a laser beam at some location, is generally understood to the optical power per unit area, which is transmitted through an imagined surface perpendicular to the propagation direction. An example is that the intensity noise of a laser normally refers to noise (fluctuations) of its optical power rather than e.g. Such uses of the term should be avoided, but in certain contexts they are nevertheless very common. Sometimes, what is actually meant is for example an optical power, an irradiance or a radiant intensity – these are examples of very different quantities which should not be confused. In other cases, intensities are meant to be quantitative measures, but used in quite inaccurate ways. Such non-quantitative statements rarely create a risk of misunderstanding. An actual numerical value is not specified in such cases. For example, such a statement could be “high intensity laser beams are used for laser material processing” – just like “the sun is very bright today”. The term intensity is often used in a non-quantitative way. Non-quantitative and Inaccurate Meanings of Intensity Certainly, for quantitative reference it is important to clearly indicate which meaning of intensity is used. However, we must deal with literature using the term in different ways, as explained in the following sections. One may recommend using optical intensity only in a non-quantitative way and only use well-defined radiometric quantities like radiant intensity and irradiance for quantitative references. The term optical intensity (or just intensity) is quite common in optical physics and technology, but it is somewhat problematic, since it is used with substantially different meanings. How to cite the article suggest additional literature Earthquakes spread out, so they do less damage the farther they get from the source.Encyclopedia > letter O > Optical intensity Optical IntensityĬategories: general optics, light detection and characterization Sunlight, for example, can be focused to burn wood. ![]() Waves can also be concentrated or spread out. For example, the longer deep-heat ultrasound is applied, the more energy it transfers. The energy effects of a wave depend on time as well as amplitude. ![]() In fact, a wave’s energy is directly proportional to its amplitude squared because Because work \(W\) is related to force multiplied by distance (\(F_x\)) and energy is put into the wave by the work done to create it, the energy in a wave is related to amplitude. The larger the displacement \(x\) the larger the force \(F = kx\) needed to create it. More quantitatively, a wave is a displacement that is resisted by a restoring force. Large ocean breakers churn up the shore more than small ones. Loud sounds have higher pressure amplitudes and come from larger-amplitude source vibrations than soft sounds. Large-amplitude earthquakes produce large ground displacements. The amount of energy in a wave is related to its amplitude. (credit: Petty Officer 2nd Class Candice Villarreal, U.S. The Richter scale rating of earthquakes is related to both their amplitude and the energy they carry. \): The destructive effect of an earthquake is palpable evidence of the energy carried in these waves. ![]()
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