Cancer that has spread to the lungs may not cause any symptoms or it may cause. 1  A cough that doesn't go away. 2  Shortness of breath. 3  Chest infections. 4  A build up of fluid between the chest wall and the lung called a pleural effusion â this in turn causes shortness of breath, chest aching, discomfort and heaviness.ancer that has spread to the lungs may not cause any symptoms or it may cause. 1  A cough that doesn't go away. 2  Shortness of breath. 3  Chest infections. 4  A build up of fluid between the chest wall and the lung called a pleural effusion â this in turn causes shortness of breath, chest aching, discomfort and heaviness.
A laser is a coherent and focused beam of photons; coherent, in this context, means that it is all one wavelength, unlike ordinary light which showers on us in many wavelengths. The acronym laser stands for light amplification by stimulated emission of radiation.. Lasers work as a result of resonant effects. The output of a laser is a coherent electromagnetic field. In a coherent beam of electromagnetic energy, all the waves have the same frequency and phase.
Such light is called coherent. Lasers produce coherent light through a process called stimulated emission. The laser contains a chamber in which atoms of a medium such as a synthetic ruby rod or a gas are excited to a high energy level. device that emits a very narrow and intense beam of light or other radiation. The light is generated by exciting the atoms of a medium, such as a crystal, gas, or liquid. The color of laser light depends on the level to which the atoms of the medium become excited.