The word laser is an acronym for the phrase “light amplification by stimulated emission of radiation. Coherent light waves are light waves that are in phase with each other. This is how lasers differ from other types of light. Spatial coherence is the outputting of a narrow beam; they can be focused on tiny spots achieving a high irradiance or they can be launched into beams of low divergence in order to concentrate their power at a large distance. Spatial coherence allows a laser to be focused to a tight spot which allows laser cutting and lithography to be possible.
A proper preheating temperature and machining parameter were found and used for the machining of square and spline members. A high power diode laser with a wavelength of 940-980 nm was used, with CBN and hard-metal ball end mills of 8 mm diameter. 2.3.2 Laser assisted milling at micro scale Laser is reported to have high flexibility to be focused and to heat up an extremely restricted area. However, the heat generated by the laser irradiation could give different impact to the machining performance, depends on the laser beam characteristics. Heated workpiece surface behaves differently during the machining process due to softening effect.
Laser Technology Abstract: A laser is a electron device that produces a very narrow, powerful beam of light. The essential components of a laser include an active medium, an energy source, and an optical cavity. The optical cavity itself is enclosed by the resonator which has a mirror at each end. The energy that is put into the laser causes the atoms of the active medium to be excited to a higher energy level. When these atoms relax back down to their ground level they emit photons, which is part of a chain reaction that may cause other atoms to go through the same energy transitions resulting in light that becomes so intense that part of it exits through one of the mirrors as a very strong beam, known as a laser.
these are stainless steel that a prescription hardenable (PH) such as 15-5PH, PH-13-8Mo and 17-4PH these alloys are used for forging. The alloys include Cr-Ni in their make-up, like austenitic materials. They have added metals such as aluminium, copper, titanium and columbium when other properties are required. These allow the stainless steels to be solution treated and age cycled, giving the material more strength. These materials, when in the annealed condition, are “soft martensitic” and are then made into “hard martensitic” by sub-zero cooling or age cycling.
The term laser is an acronym. It stands for "light amplification by stimulated emission of radiation". They produce a narrow, intense beam of coherent light. In a laser the atoms or molecules of a crystal, like ruby or garnet-or of a gas, liquid, or other substance-are excited so that more of them are at higher energy levels than are at lower energy levels. If a photon whose frequency corresponds to the energy difference between the excited and ground states strikes an excited atom, the atom is stimulated, as it falls back to a lower energy state, to emit a second photon of the same frequency, in phase with and in the same direction as the bombarding photon.
A high energy laser pulse is focused on the target which can be a gas, liquid, or solid substance generating a dielectric breakdown or “plasma-spark”. This high-temperature atomization provides sufficient energy for the transition of atoms into different atomic energy levels. The atoms thus decay resulting in narrow “fingerprint” of elemental emission line spectra. The integration of laptop computers, optical fiber spectrometers and small high power laser transmitters has directed to the development of portable LIBS analytical equipment. LIBS portable analyzer systems are capable of real-time qualitative & quantitative in-situ analysis with small or no sample
LIDAR, stands for Light Detection And Ranging, is an active optical remote sensing instrument. It is an innovative technique that uses laser for probing the planetary atmosphere [1, 2, and 3]. Atmospheric LIDARs use narrow pulsed lasers. Flash-lamp pumping is generally employed in generation of Q-switched lasers. Flash-lamp pumped (FLP) systems produce lasers at low repetition rate with high pulse energies.
The schematic diagram of a magnetron gun is shown in Figure 11. Magnetron sputtering creates most uniform and most cost effective films. During magnetron sputtering energetic electron escape from the primary magnetic trap between the inner and outer magnets, and in the balanced magnetic field these electrons go to the anode. It is the primary trap that is responsible for the formation of the dense plasma directly in front of the sputtering target. A magnetron consists of a plate of the material of which all or part of the coating is consisting with magnets arranged behind it with alternating polarity.
Then the beam passed down through the main electron gun column into the specimen chamber. Here it is focused onto a fine spot. Then the surface of the sample is scanned rapidly. As the result of ionization processes secondary electrons are emitted from the sample. From the primary beam (generated by the electron gun) some electrons are get reflected or bounced back by the sampl... ... middle of paper ... ...hich describes the angle at which a beam of X-rays of a particular wavelength diffracts from a crystalline surface.
However, these plasma electrons can inter-mediate the forces of laser fields on ions by generating strong quasi-static electric fields which arises from the charge separation due to the laser propagation. To accelerate the ion or proton need strong enough static electric field which can be explained best in two scenarios. These scenarios are I. Radiation Pressure Acceleration ( RPA ) ii. Target Normal Sheath Acceleration ( TNSA ).