Atomic and molecular spectroscopy with lasers

• Grant number: 97/05257-5
• Support Opportunities: Research Projects - Thematic Grants
• Start date: April 01, 1998
• End date: July 31, 2001
• Field of knowledge: Physical Sciences and Mathematics - Physics - Atomic and Molecular Physics
• Principal Investigator: Artemio Scalabrin
• Grantee: Artemio Scalabrin
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Pesquisadores principais: Daniel Pereira
• Associated research grant(s): 98/06536-8 - Laser deceleration of a calcium atomic beam atomic with a frequency doubled diode laser., AR.EXT

Abstract

The invention of the laser in 1960 has resulted in important consequences for science and technology. In physics its use as monochromatic and strong source of radiation has made a revolution to optical well established spectroscopy techniques like Raman scattering and luminescence, as also made possible the development of new techniques like saturation spectroscopy which can used to resolve homogeneous lines buried in an inhomogeneous l ineshape several orders of magnitude larger. This allowed the determination of spectroscopic and universal constants with high degree of accuracy. A good example is the determination of the speed of light. This was done with a He-Ne laser operating in 3.39 @m stabilized against a methane, CH4, transition by measuring independently the wavelength k, and the frequency, v, resulting the speed of the light from the product of these two quantities, c=?,xv. These measurements done in 1972 increased by I 00 times the precision of the speed of light and made it the best determined fundamental constant c= 299 792 458 m/s _ 1.2m/s. The uncertainty in c was due to the uncertainty in the determination of the wavelength of 86Kr which was A, %=_4xlO-9. Later the CCDM adopted the above value of c as definition of the speed of light and the meter is now defined in terms of the second. Frequency is the physical quantity determined with the best accuracy. Therefore there is a great interest in reducing the determination of other quantities to a frequency (or time) measurement. As frequency, time and length can be in principle defined using the same oscillator it is very important to develop stabilized lasers which can be used as standards of frequency time and length. In order to compare the frequency of a laser to the primary Cs standard it is necessary to multiply the frequency of the Cs standard up to the frequency to be measured. This is done by using a chain of oscillators each one phase locked to the previous lower frequency. Recently, in Germany, a visible dye laser was stabilized to the 3p I - ISO transition in 657 nm of Ca with an uncertainty of one part in 1 0 1 3. This turns it possible the realization of spectroscopy in the frequency domain in the visible.Our research group has been pursuing some lines in this research area in the last 15 years. We developed molecular lasers in the Infrared and Far Infrared. We discovered more than 500 lines with wavelengths in the range of 30 [tm to 3 mm... (AU)