Abstract Stimulated emission of radiation (laser action) is produced in materials generally classed as dyes. These dyes may be dissolved in a liquid solution. A quantity of dye in a flowing liquid solution in a module or cavity is pumped or exicted by a laser beam radiating in the ultraviolet region which is focused to a line with a cylindrical lens. A rectangular cross sectional beam of such radiation is produced by a pulsed crossed field nitrogen gas laser. The focused line which is transverse to the beam produced by the exciting laser, and transverse to the direction of the flowing dye lies near the surface of the dye material in the cell, and is substantially as long as the cell is wide. The cell lies within an intensifying optical cavity which may be formed by a 100 percent reflecting mirror and a partially reflecting mirror both perpendicular to the line of focus of the pumping radiation. The stimulated emission from the dye material is characterized by a short pulse width and a little loss of energy between the two lasers. High pulse rates with dye circulation, and high conversion efficiencies of the dye when so pumped, are obtained. For frequency adjustment the optical cavity substitutes for the 100 percent mirror a grating or Littrow prism at the appropriate angle. Further spectral narrowing may be obtained by inserting a tilted Fabry-Perot etalon in the cavity. By using such a frequency tuner and a plurality of dye materials which emit stimulated radiation over different portions of the spectrum, the present device can provide laser radiation for virtually the whole visible spectrum and into the infrared and ultraviolet.
Apparatus according to claim 1 wherein said pumping laser means is a crossed field gas discharge laser.
Claim 2
Dependent Claim
14 words
Apparatus according to claim 2 wherein said emitted radiation has a wavelength of 3,371A.
Claim 3
Dependent Claim
50 words
Apparatus according to claim 1 wherein said means for receiving said laser material from said liquid pump includes a reticulated structure positioned transverse to said flow direction and substantially covering the cross sectional area of said means, whereby said laser material received from said pump passes through said reticulated structure.
Claim 4
Dependent Claim
12 words
Apparatus according to claim 1 wherein said laser material is 3-Amino Phthalimide.
Claim 5
Dependent Claim
23 words
Apparatus according to claim 1 wherein said stimulated radiation emitted from said laser has a wavelength greater than 4,900A and less than 5,100A.
Claim 6
Dependent Claim
253 words
In apparatus for producing stimulated radiation in a flowing liquid laser material comprising; liquid pumping means for circulating said laser material, pumping laser means emitting a beam of pumping radiation, focusing means positioned to focus said beam into the population inversion region of said liquid laser material and optical cavity means for intensifying stimulated radiation emitting from said liquid laser material the improvement comprising: dye module means coupled in circuit with said liquid pumping means and through which liquid laser material flows, said dye module means having a front windoW through which said beam passes, oppositely disposed side windows through which the stimulated emission produced in the liquid laser material may pass, and a rear portion hydrodynamically contoured which in combination with said front window define between said side windows a flow channel having a liquid laser material inlet and a liquid laser material outlet, said flow channel providing substantially laminar flow through a restricted portion, said restricted portion defining the population inversion region wherein the flow velocity is increased, said restricted portion having a substantially rectangular cross section normal to the direction of flow of said liquid laser material, the cross-sectional area normal to the direction of flow of said liquid laser material of said flow channel, beginning at said liquid material inlet and progressing in the direction of flow through said restricted portion to said liquid material outlet, smoothly decreasing in cross-sectional area to a minimum cross-sectional area in said restricted portion and then smoothly increasing to said liquid material outlet.