Patent ID: 6693942
Filing Date: 2004-02-17
Classification: H01S

Abstract:
An up-conversion diode-pumped alkali laser (UC-DPAL), comprising:a laser cavity formed by an input mirror and an output minor, resonant at a wavelength &lgr;03 or &lgr;04 corresponding to wavelengths of the D1â€² or D2â€² transitions of an alkali atomic vapor; a gain medium within said resonant cavity, said gain medium comprising a mixture of one or more buffer gases and an alkali vapor whose D1â€² or D2â€² transition wavelengths match that of said resonant laser cavity, wherein said mixture collisionally broadens the optical transitions, renders the transitions spectrally homogeneous with predominantly Lorentzian lineshapes, and facilitates increased spectral coupling between the pump radiation and alkali atom absorption, wherein the buffer gas collisionally relaxes doubly-excited alkali atoms from the 2D3/2 level to the n+1 2P1/2 and 2P3/2 levels (the upper laser levels for the two UC-DPAL laser transitions, n+1 2P3/2-n 2S1/2 or the n+1 2P1/2-n 2S1/2), and wherein the buffer gas composition and density are chosen so that this relaxation rate substantially exceeds the radiative relaxation rate of the 2D3/2 level; a first continuous wave (CW) semiconductor diode pump laser (or a first (CW) laser diode array) emitting at a wavelength suitable for optically exciting said alkali vapor at a wavelength of the first series D1 or D2 transitions of said alkali vapor, wherein said first CW semiconductor diode pump laser (or said first CW laser diode array) is operably positioned for optically exciting said alkali vapor; and a second CW semiconductor diode pump laser (or a second CW laser diode array) emitting at a wavelength suitable for further optically exciting alkali atoms excited by said first CW semiconductor diode pump laser, to the n 2D3/2 (or similar) electronic level of the alkali atom, said first CW semiconductor diode pump laser (or said first CW laser diode array) and said second CW semiconductor diode pump laser (or said second CW laser diode array) together producing a population inversion and laser emission at the wavelength of the second series D1â€² or D2â€² transitions of said alkali vapor, wherein said second CW semiconductor diode pump laser (or said second CW laser diode array) is operably directed onto said alkali vapor.