Frederick "Frits" Zernike[3] was born on 16 July 1888 inAmsterdam, Netherlands to Carl Friedrich August Zernike and Antje Dieperink. Both parents were teachers of mathematics, and he especially shared his father's passion for physics. In 1905 he enrolled at theUniversity of Amsterdam, studying chemistry (his major), mathematics and physics.
In 1930, Zernike was conducting research intospectral lines when he discovered that the so-calledghost lines that occur to the left and right of each primary line inspectra created by means of adiffraction grating, have their phase shifted from that of the primary line by 90 degrees.[citation needed][5] It was at a Physical and Medical Congress inWageningen in 1933, that Zernike first described his phase contrast technique in microscopy. He extended his method to test the figure of concave mirrors. His discovery lay at the base of the first phase contrast microscope, built during World War II.[citation needed]
Zernike's work helped awaken interest incoherence theory, the study of partially coherent light sources. In 1938 he published a simpler derivation of Van Cittert's 1934 theorem on the coherence of radiation from distant sources, now known as theVan Cittert–Zernike theorem.[6][7]
^Zernicke, Frits (1935). "Das Phasenkontrastverfahren bei der mikroskopischen Beobachtung".Zeitschrift für technische Physik.16:454–457.
^Van Cittert, P. H. (1934). "Die Wahrscheinliche Schwingungsverteilung in Einer von Einer Lichtquelle Direkt Oder Mittels Einer Linse Beleuchteten Ebene".Physica.1 (1–6):201–210.Bibcode:1934Phy.....1..201V.doi:10.1016/S0031-8914(34)90026-4.
