1967 – American physicist Theodore Maiman is given a patent for his ruby laser systems, the world’s first laser.
A ruby laser is a solid-state laser that uses a synthetic ruby crystal as its gain medium. The first working laser was a ruby laser made by Theodore H. “Ted” Maiman at Hughes Research Laboratories on May 16, 1960.[1][2]
Ruby lasers produce pulses of coherent visible light at a wavelength of 694.3 nm, which is a deep red color. Typical ruby laser pulse lengths are on the order of a millisecond.
Design
See also: Laser construction
A ruby laser most often consists of a ruby rod that must be pumped with very high energy, usually from a flashtube, to achieve a population inversion. The rod is often placed between two mirrors, forming an optical cavity, which oscillate the light produced by the ruby’s fluorescence, causing stimulated emission. Ruby is one of the few solid state lasers that produce light in the visible range of the spectrum, lasing at 694.3 nanometers, in a deep red color, with a very narrow linewidth of 0.53 nm.[3]
The ruby laser is a three level solid state laser. The active laser medium (laser gain/amplification medium) is a synthetic ruby rod that is energized through optical pumping, typically by a xenon flashtube. Ruby has very broad and powerful absorption bands in the visual spectrum, at 400 and 550 nm, and a very long fluorescence lifetime of 3 milliseconds. This allows for very high energy pumping, since the pulse duration can be much longer than with other materials. While ruby has a very wide absorption profile, its conversion efficiency is much lower than other mediums.[3]
In early examples, the rod’s ends had to be polished with great precision, such that the ends of the rod were flat to within a quarter of a wavelength of the output light, and parallel to each other within a few seconds of arc. The finely polished ends of the rod were silvered; one end completely, the other only partially. The rod, with its reflective ends, then acts as a Fabry–Pérot etalon (or a Gires-Tournois etalon). Modern lasers often use rods with antireflection coatings, or with the ends cut and polished at Brewster’s angle instead. This eliminates the reflections from the ends of the rod. External dielectric mirrors then are used to form the optical cavity. Curved mirrors are typically used to relax the alignment tolerances and to form a stable resonator, often compensating for thermal lensing of the rod.[3][4]
Ruby also absorbs some of the light at its lasing wavelength. To overcome this absorption, the entire length of the rod needs to be pumped, leaving no shaded areas near the mountings. The active part of the ruby is the dopant, which consists of chromium ions suspended in a synthetic sapphire crystal. The dopant often comprises around 0.05% of the crystal, and is responsible for all of the absorption and emission of radiation. Depending on the concentration of the dopant, synthetic ruby usually comes in either pink or red.[3][4]
1934 – Catherine McGuinness, Irish lawyer, judge, and politician
Catherine Elizabeth McGuinness (née Ellis; born 14 November 1934) is a retired Irish judge who served as a Justice of the Supreme Court from 2000 to 2006, Judge of the High Court from 1996 to 2000, Judge of the Circuit court from 1994 to 1996 and a Senator for the University of Dublin from 1979 to 1981 and between 1983 to 1987. She was appointed by President Michael D. Higgins to the Council of State in January 2012. She had previously been a Member of the Council of State from 1988 to 1990, upon being appointed by President Patrick Hillery.[1][2]
She was President of the Law Reform Commission from 2007 to 2009. In May 2013 she was appointed Chair of the National University of Ireland Galway Governing Authority.[3]
Biography
Born in Belfast, Northern Ireland, McGuinness was educated in Alexandra College, Trinity College Dublin and the King’s Inns.[4] In the 1960s she worked for the Labour Party.[5] She was called to the Irish bar in 1977 at age 42. In 1989 she was called to the Inner Bar.[6]
In 1979 she was elected as an independent candidate to Seanad Éireann at a by-election on 11 December 1979 in the Dublin University constituency following the resignation of Conor Cruise O’Brien, taking her seat in the 14th Seanad.[1] She was re-elected at the 1981 elections to the 15th Seanad, and in 1983 to the 17th Seanad, where she served until 1987. She lost her seat to David Norris.[5] She was appointed to the Council of State on 2 May 1988 by President Patrick Hillery and served until 1990.[6]
She was appointed a judge in the Circuit Court in 1994, the first woman to hold that office in the Ireland.[5] In 1996 she was appointed to the High Court and remained there until her appointment to the Supreme Court in January 2000.[7][8]
In November 2005 she was appointed Adjunct Professor at the Faculty of Law, National University of Ireland, Galway.[9] She was also appointed President of the Law Reform Commission in 2005, and held that position until 2011.[6]
In April 2009 she was awarded a “Lord Mayor’s Award” by Dublin Lord Mayor Eibhlin Byrne “for her contribution to the lives of children and families in the city through her pioneering work”.[10] In September 2010 she was named as one of the “People of the Year” for “her pioneering, courageous and long-standing service to Irish society”.[11][12] In November 2012 she won the ‘Irish Tatler Hall of Fame Award'[13]
In addition to her judicial career, McGuinness has served on the Employment Equality Agency, Kilkenny Incest Investigation, the Forum for Peace and Reconciliation,[14] the National Council of the Forum on End of Life in Ireland,[4] and the Irish Universities Quality Board.[15] In June 2011 she became patron of the Irish Refugee Council.[16] In November 2011 she was appointed Chairperson of the “Campaign for Children”[17]
She has received honorary doctorates from the University of Ulster, the National University of Ireland, the University of Dublin and the Higher Education and Training Awards Council (HETAC).[14]
In February 2013 McGuinness accepted the Honorary Presidency of Trinity College, Dublin’s Free Legal Advice Centre
In January 2014 she was appointed by Minister for Communications, Energy and Natural Resources, Pat Rabbitte to chair the expert panel to oversee the preparation of reports on the best underground route options to compare with the Grid Link and Grid West high voltage power lines in Ireland.[18]
In March 2015 she received an Alumni Award from Trinity College Dublin.[19]
She was married to broadcaster and writer Proinsias Mac Aonghusa and has three children.
(Proinsias Mac Aonghusa (English: Francis McGuinness; 23 June 1933 – 28 September 2003) was an Irish journalist, writer, tv presenter and campaigner.)
Catherine McGuinness Fellowship on Children’s Rights and Child Law
In November 2014 the Children’s Rights Alliance established the Catherine McGuinness Fellowship on Children’s Rights and Child Law, a one-year Fellowship Programme for newly qualified barristers to work as part of their Legal and Policy Team on law and policy reform for children in the area of children’s rights and child law in the Irish context. The Programme was developed in partnership with the Bar Council of Ireland and with the support of the Family Lawyers Association of Ireland.[20]
The Fellowship was launched by the Chief Justice of Ireland, Susan Denham who described McGuinness as “an advocate at heart” and a “patriot, in the true sense of the word” who “stands up for the rights of others, particularly those who are marginalised and vulnerable in our society.” [21]
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