1. 19th Century
1.1. W Wollaston (1802)
1.1.1. By improving Newton's model , work on lens to focus sun's spectrum
1.2. J Fraunhofer (1814)
1.2.1. 1st Spectroscope invented by flame mechanism.
1.3. Thomas Young, François Arago and Augustin-Jean Fresnel(before 1830)
1.3.1. Works on diffraction, dispersion and interference phenomenon of light
1.4. Wheatstone (1835)
1.4.1. reported that different metals could be easily distinguished by the different bright lines in the emission spectra of their sparks
1.5. upto end of mid 19th century
1.5.1. other scientists introducing diff. terms & phenomenon.
1.6. Maxwell (1873)
1.6.1. Eqn of EM waves
1.7. late 19th century
1.7.1. after em waves equation scientists works on different EM waves and related spectroscopy.
2. 20th Century
2.1. Planck's and Einstein's era
2.1.1. quantum theory
2.2. C V Raman(1928)
2.2.1. Raman Effect
2.3. E Lehrer (1937)
2.3.1. created the first fully-automated spectrometer
2.4. up to late 20th century
2.4.1. works on spectrometer accuracy and improvement.
3. 21th Century
3.1. Currently working on molecular spectroscopy, development of prosthetic sensors, treatment and diagnoses in psychosomatic area, gravitational waves and Hawking's radiation etc.,
4. 17th Century
4.1. A Kircher (1646) ,J M Marci (1648), Robert Boyle (1664), and F M Grimaldi (1665),
4.1.1. they all are know about ablity of Prism and work on it.
4.2. Newton (1666-1672)
4.2.1. Generally by Prism ,his experiments and theoretical explanations of dispersion of light in his Opticks.
5. 18th Century
5.1. Newton , Hooke, Huygens, Young
5.1.1. They all are starting explore about different nature of light , and cover it up to first indications that spectra were associated uniquely with chemical constituents.