Introduction to Polarized Light
1. Application of polarized lightTo measure the polarization of an electron beam, a Mott detector is required. In order to maximize the spin-orbit coupling, it is necessary that the electrons arrive near to the nuclei of the target. To achieve this condition, a system of electron optics is usually present, in order to accelerate the beam up to keV or to MeV energies. Since standard electron detectors count electrons being insensitive to their spin, after the scattering with the target any information about the original polarization of the beam is lost. Nevertheless, by measuring the difference in the counts of the two detectors, the asymmetry can be evaluated and, if the Sherman function is known from previous calibration, the polarization can be calculated by inverting the last formula.In order to characterize completely the in-plane polarization, setups are available, with four channeltrons, two devoted to the left-right measure and two devoted to the up-right measure.ExampleIn the panel it is shown an example of the working principle of a Mott detector, supposing a value for S ( ) 0.5 displaystyle S(theta )0.5. If an electron beam with a 3:1 ratio of spin-up over spin-down electrons collide with the target, it will be splitted with a ratio 5:3, according to previous equation, with an asymmetry of 25%.------2. Publications of polarized lightHis major scientific publications included works on electromagnetism, dynamics and Bessel functions. He also wrote a treatise on gyrostats.His FRS candidacy form itemised the following:'Absolute Measurements in Electricity and Magnetism' (1889)'Theory and Practice of Absolute Measurements in Electricity Magnetism' (vol i, 1888; vol ii, in two parts, 1893)'A Treatise on Magnetism and Electricity''On the Determination in Absolute Units of the Intensity of Powerful Magnetic Fields' (Phil Mag, 1883)'On the Dynamical Theory of Electro-magnetic Action' (ibid, 1890)'On the Calculation of the Induction Coefficients of Coils' (ibid, 1892)'On a New Reflecting Galvanometer of great sensibility, and on New Forms of Astatic Galvanometers,' jointly with T Gray (Proc Roy Soc, 1884)'On the Relation between the Electrical Qualities and the Chemical Composition of Glass and Allied Substances,' Part I, jointly with T Gray and J J Dobbie (Proc Roy Soc, 1884)1888 Diary of cruise to Australia'On the Electro-magnetic Theory of the Rotation of the Plane of Polarized Light' (Rept Brit Assoc, 1891).Later works included:Treatise on Bessel Functions (1895) with G B MathewsMagnetism and Electricity (1898)Dynamics and Property of Matter (1901)The Scientific Work of Lord Kelvin (1908)Dynamics (1911) with his son James GrayTreatise on Gyrostatics and Rotational Motion (1919)------3. Lisa Portes of polarized lightLisa Portes is an award-winning director, educator, advocate and leader. She heads of the MFA Directing program at The Theatre School at DePaul University. She serves on the board of the Theatre Communications Group, the Executive Board of the Society of Stage Directors and Choreographers, and is a founding member of the Latinx Theater Commons. Primarily a director of new American plays and musicals, Ms. Portes' work has been seen regionally at California Shakespeare Theater, Guthrie Theatre, Denver Center for the Performing Arts, Cincinnati Playhouse, South Coast Repertory, McCarter Theatre, and the John F. Kennedy Center for the Performing Arts. In Chicago she has directed for Steppenwolf Theatre Company, Goodman Theatre, Victory Gardens Theatre, TimeLine Theatre Company, American Blues Theatre, Silk Road Rising, Next Theatre, and Teatro Vista. New York credits include work at Playwrights Horizons, Soho Rep, New York Theatre Workshop, the Flea Theatre, and The Public Theater. Ms Portes served as the Associate Director of the Tony Award-winning musical The Who's Tommy, and staged its international productions in Canada, Germany, and the U.K, as well as its 20th anniversary remount at the Stratford Theatre Festival in 2013. In 2016, Ms. Portes was awarded the SDC Zelda Fichandler Award.------4. Research and medical use of polarized lightThe main medical use emerging in this field is for research on eye development and ocular diseases. New research studies on ocular gene expression are being performed using cephalopod eyes due to the evidence of their convergent evolution with the analogous human eye. These studies replace the previous Drosophila studies for gene expression during eye development as the most accurate, although Drosophila studies remain the most common. The conclusion that they are analogous lends credibility to their comparison for medical use in the first place, since the trait in both would have been shaped through natural selection by similar pressures in similar environments; meaning there would be similar expression of ocular disease in both organisms eyes.An advantage of cephalopod eye experimentation is that cephalopods can regenerate their eyes due to their ability to re-enable their developmental processes, which allows studies of the same cephalopod to continue past one trial sample when studying the effects of disease. This also permits for a more complex study concerning how regeneration may be conserved in cephalopod genomes and if it may be somewhat conserved in the human genome alongside the genes expressing for the camera eye.------5. Shandite of polarized lightShandite is a sulfide mineral with chemical formula: Ni3Pb2S2. It was discovered in 1950 and named after Scottish petrologist, Samuel James Shand (18821957). It is characterized by a metallic luster and a brass-yellow color. It has a specific gravity of 8.92, and a Mohs hardness value of 4. Shandite is commonly found as an inclusion in other minerals such as serpentine.Its crystal system is trigonal hexagonal scalenohedral with symbol 32/m. It belongs to the space group R3m. Shandite is an anisotropic mineral, which means it has different properties when being viewed from different directions. In cross-polarized light it appears as gray blue or yellow-brown colors. It also has very distinct relief, which means it stands out against its mounting medium and can be easily seen. It has an index of refraction of 1.54, which is the measure of the speed of light through the substance. In plane polarized light, shandite has a creamy white color and distinct pleochroism, which is the property that makes it appear to be different colors at different angles. It has strong birefringence, which is the decomposition of light into two rays, and appears dark blue and gray.------6. Evolutionary debate of polarized lightDisagreement on whether the evolution of the camera eye within cephalopods and within vertebrates is a parallel evolution or a convergent evolution still exists, although is mostly resolved. The current standing is that of a convergent evolution for their analogous camera-type eye.Parallel evolutionThose maintaining that it is a parallel evolution state that there is evidence that there was a common ancestor containing the genetic information for this eye development. This is evidenced by all bilaterian organisms containing the gene Pax6 which expresses for eye development.Convergent evolutionThose supporting a convergent evolution state that this common ancestor would have preceded both cephalopods and vertebrates by a significant margin. The common ancestor with the expression for camera-type eye would have existed approximately 270 million years before the evolution of camera-type eye in cephalopods and approximately 110 to 260 million years before the evolution of camera-type eye in vertebrates. Another source of evidence for this is the differences of expression due to independent variants of Pax6 arising in both cephalopods and vertebrates. Cephalopods contain five variants of Pax6 in their genomes which independently arose and are not shared by vertebrates, although they allow for a similar gene expression when compared to the Pax6 of vertebrates.------7. Professor in Amsterdam of polarized lightShortly after his discovery, Zeeman was offered a position as lecturer in Amsterdam, where he started to work in Autumn of 1896. In 1900 this was followed by his promotion to professor of physics at the University of Amsterdam. In 1902, together with his former mentor Lorentz, he received the Nobel Prize for Physics for the discovery of the Zeeman effect. Five years later, in 1908, he succeeded Van der Waals as full professor and Director of the Physics Institute in Amsterdam.In 1918 he published "Some experiments on gravitation: The ratio of mass to weight for crystals and radioactive substances" in the Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen, experimentally confirming the equivalence principle with regard to gravitational and inertial mass.A new laboratory built in Amsterdam in 1923 was renamed the Zeeman Laboratory in 1940. This new facility allowed Zeeman to pursue refined investigation of the Zeeman effect. For the remainder of his career he remained interested in research in Magneto-Optics. He also investigated the propagation of light in moving media. This subject became the focus of a renewed interest because of special relativity, and enjoyed keen interest from Lorentz and Einstein.Later in his career he became interested in mass spectrometry.------8. Determination of polarized lightkd, is known as the specific equilibrium dissociation constant for formation of the enzyme-substrate complex. kd is used as a measure of affinity, with higher values indicating a lower affinity.For the given equation (E enzyme, S substrate, P product)k1 k2E S ES E Pk-1kd would be equivalent to k-1/k1, where k1 and k-1 are the rates of the forward and backward reaction, respectively in the conversion of individual E and S to the enzyme substrate complex.Application to enzyme kineticsThe chemical specificity of an enzyme for a particular substrate can be found using two variables that are derived from the Michaelis-Menten equation. km approximates the dissociation constant of enzyme-substrate complexes. kcat represents the turnover rate, or the number of reactions catalyzed by an enzyme over the enzyme amount. kcat over km is known as the specificity constant, which gives a measure of the affinity of a substrate to some particular enzyme. Also known as the efficiency of an enzyme, this relationship reveals an enzyme's preference for a particular substrate. The higher the specificity constant of an enzyme corresponds to a high preference for that substrate.------9. Life and work of polarized lightHilda Hnchen received her doctorate in 1943 from the University of Hamburg under the supervision of Fritz Goos, with a dissertation titled ber das Eindringen des totalreflektierten Lichtes in das dnnere Medium ("On the penetration of totally reflected light into the rarer medium"). During World War II she worked as a "managing" research assistant at the State Physics Institute in Hamburg (to allow male academics to return after military service, women could be employed as managing assistants only).She concurrently worked at the Physical-Chemical Research Institute in Kiel on war research contracts and was listed in the register of sponsorships of the Reichsforschungsrat ("Reich Research Council"). From 1949 to 1951 she was a referee for the chemistry journal Chemisches Zentralblatt. Around 1975 she was the chairman of the local Cologne chapter of Deutscher Akademikerinnenbund ("Association of German women academics").With her doctoral advisor Fritz Goos, Hnchen discovered the Goos-Hnchen effect, which is an optical phenomenon in which linearly polarized light undergoes a small lateral shift when totally internally reflected.In 1946 she married physicist Albert Hermann Lindberg (born 1914), who before his retirement in 1979 served as the Vice President and Development Director of Leybold AG. They had three daughters - Renate, Claudia, and Dorothea.------10. S. Pancharatnam of polarized lightShivaramakrishnan Pancharatnam (19341969) was an Indian physicist who did significant work in the field of optics. He is noted for his discovery of a type of geometric phase sometimes known as Pancharatnam phase for polarized beams passing through crystals. He was born in Calcutta in West Bengal, India in 1934. He was elected a Fellow of the Indian Academy of Sciences at the early age of 25. He was a reader at the Department of studies in Physics, University of Mysore from 1961-1964. From 1964 until his death in 1969 at the age of 35 he was a Research Fellow of St Catherine's College, Oxford, working in association with George William Series. His publications for this period were mainly concerned with the theory of effects found in experiments on optical pumping, e.g. double refraction in a gas due to spin alignment. Professor Series has written an introduction to the life and work of Pancharatnam. He also prepared, for the Proceedings of the Royal Society, the last three papers from notes left by Pancharatnam.In 1956, Pancharatnam was studying interference figures produced by light waves in crystal plates, under his advisor C. V. Raman, when he discovered the properties of what is now known as the geometric phase, and which predated Michael Berry's work on the topic from 1983.