caa a22 4500 606243836 CHVBK 20210128101326.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s12596-014-0219-4 doi (NATIONALLICENCE)springer-10.1007/s12596-014-0219-4 Identification of optical parameters for determination of radiance [Elektronische Daten] [Pratik Shukla, Jonathan Lawrence] The ‘brightness' of coherent beams such as lasers is known as ‘radiance' in radiometric terms. It is a concept which is rarely taken into account in laser material processing, laser system design, and for the characterization of laser beams. The typical beam parameters such as: laser power; spot size; intensity; wavelength; beam divergence and the beam propagation factor - M2, combined together are factors which determine the ‘radiance' of lasers or energy beams in general. The concept of ‘brightness' (‘radiance' in particular), and how the laser beam parameters contribute to affect ‘radiance', has not so far been reported in previous literature. Thus, we have investigated the theoretical ‘radiance' for each parameter in relation to one another. In addition, a rather suitable empirical equation to determine the ‘radiance' was also introduced herein, since, the existing equation for calculating ‘brightness' do not employ the total power intensity of the beam. Based on this, we consider ‘power density' rather than the ‘output power' for determining radiance of a selected 1.064μm wavelength Nd:YAG laser for a set laser processing parameter window. The analytical investigation firstly concluded that the inclusion of ‘power density' into the equation takes in account of ‘spot size' and ‘laser power' to cover all laser beam parameters. Secondly, the results have shown wavelength to be the most contributory parameter to influence the radiance value followed by power density, M2, laser power and lastly the spot size of the laser beam. This was for a set-condition applied, but is generically applicable to different conditions and parameters, whereby, the same tendency would occur. This novel concept of brightness (radiance), of light sources such as a laser beam is not just useful for process control during laser material processing, but could prove to be a very effective concept for laser beam characterization, and in laser system design for enhancing the ‘brightness' or ‘radiance' of lasers. Also not just lasers but, the concept could be applicable for other energy beams in general. The Optical Society of India, 2014 Brightness nationallicence Radiance nationallicence Luminescence nationallicence Lasers nationallicence Beam Characterization nationallicence Shukla Pratik Laser Engineering and Manufacturing Research Group, Faculty of Science and Engineering, University of Chester, Parkgate Road, CH1 4BJ, Chester, United Kingdom aut Lawrence Jonathan Laser Engineering and Manufacturing Research Group, Faculty of Science and Engineering, University of Chester, Parkgate Road, CH1 4BJ, Chester, United Kingdom aut Journal of Optics Springer India 44/1(2015-03-01), 12-19 0972-8821 44:1<12 2015 44 12596 https://doi.org/10.1007/s12596-014-0219-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s12596-014-0219-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shukla Pratik Laser Engineering and Manufacturing Research Group, Faculty of Science and Engineering, University of Chester, Parkgate Road, CH1 4BJ, Chester, United Kingdom aut NATIONALLICENCE 700 1- Lawrence Jonathan Laser Engineering and Manufacturing Research Group, Faculty of Science and Engineering, University of Chester, Parkgate Road, CH1 4BJ, Chester, United Kingdom aut NATIONALLICENCE 773 0- Journal of Optics Springer India 44/1(2015-03-01), 12-19 0972-8821 44:1<12 2015 44 12596