Backward stimulated rayleigh-bragg scattering devices based on multi-photon absorbing materials and their applications

Abstract

The present invention relates to a method and system of generating backward stimulated Rayleigh-Bragg scattering by focusing activating radiation through a multi-photon absorbing dye solution, thereby producing coherent output radiation with no measured frequency shift and measured pump threshold values independent of the spectral line width of the input activating radiation.

1 . A system for generating backward stimulated Rayleigh-Bragg scattering, said system comprising: 
 a source of activating radiation;    a scattering cell containing a multi-photon active medium which exhibits no linear/one-photon absorption but possesses multi-photon absorption at the activating radiation's wavelength; and    a first focusing lens positioned to receive radiation from the source of activating radiation and focus it into the scattering cell under conditions effective to permit multi-photon absorption within the scattering cell, thereby producing output radiation with backward stimulated Rayleigh-Bragg scattering.    
   
   
       2 . The system according to  claim 1 , wherein the output radiation possesses the same frequency as said activating radiation.  
   
   
       3 . The system according to  claim 1 , wherein the output radiation possess a different frequency than said activating radiation.  
   
   
       4 . The system according to  claim 1 , wherein the source of activating radiation is a laser.  
   
   
       5 . The system according to  claim 4 , wherein the laser is pumped.  
   
   
       6 . The system according to  claim 4 , wherein the laser is pulsed.  
   
   
       7 . The system according to  claim 1 , wherein the multi-photon active medium comprises a multi-photon absorbing organic dye solution.  
   
   
       8 . The system according to  claim 7 , wherein the multi-photon absorbing dye has the following structure:  
     
       
         
         
             
             
         
       
     
   
   
       9 . The system according to  claim 1 , wherein said source of activating radiation, said scattering cell, and said first focusing lens are positioned to direct the output radiation toward said source of activating radiation in a direction opposite the activating radiation leaving said source of activating radiation.  
   
   
       10 . The system according to  claim 1  further comprising: 
 a beam splitter, wherein said source of activating radiation, said scattering cell, said first focusing lens, and said beam splitter are positioned to direct the output radiation in a direction opposite the activating radiation leaving said source of activating radiation until after the output radiation passes through said first focusing lens and contacts said beam splitter.    
   
   
       11 . The system according to  claim 10  further comprising: 
 a second focusing lens, wherein said scattering cell is positioned between the first and second focusing lenses.    
   
   
       12 . A method of generating backward stimulated Rayleigh-Bragg scattering, said method comprising: 
 providing a source of activating radiation;    providing a scattering cell containing a multi-photon active medium which exhibits no linear/one-photon absorption but possesses multi-photon absorption at the activating radiation's wavelength;    providing a first focusing lens positioned to focus the activating radiation into the scattering cell under conditions effective to permit multi-photon absorption within the scattering cell; and    directing activating radiation through said first focusing lens into said scattering cell containing scattering medium, thereby producing output radiation with backward stimulated Rayleigh-Bragg scattering.    
   
   
       13 . The method according to  claim 12 , wherein the output radiation possesses the same frequency as said activating radiation.  
   
   
       14 . The method according to  claim 12 , wherein the output radiation possesses a different frequency from the activating radiation.  
   
   
       15 . The method according to  claim 12 , wherein the source of activating radiation is a laser.  
   
   
       16 . The method according to  claim 15 , wherein the laser is pumped.  
   
   
       17 . The method according to  claim 15 , wherein the laser is pulsed.  
   
   
       18 . The method according to  claim 12 , wherein said active medium comprises a multi-photon absorbing organic dye solution.  
   
   
       19 . The method according to  claim 12 , wherein the multi-photon absorbing dye is has the following structure:  
     
       
         
         
             
             
         
       
     
   
   
       20 . The method according to  claim 12 , wherein said source of activating radiation, said scattering cell, and said first focusing lens are positioned to direct the output radiation toward said source of activating radiation in a direction opposite the activating radiation leaving said source of activating radiation.  
   
   
       21 . The method according to  claim 12  further comprising: 
 providing a beam splitter, wherein said source of activating radiation, said scattering cell, said first focusing lens, and said beam splitter are positioned to direct the output radiation in a direction opposite the activating radiation leaving said source of activating radiation until after the output radiation passes through said first focusing lens.    
   
   
       22 . The method according to  claim 21  further comprising: 
 providing a second focusing lens, wherein said scattering cell is positioned between the first and second focusing lenses.    
   
   
       23 . The method according to  claim 12  further comprising: 
 utilizing the activating radiation as an intracavity Q-switching element for Q-switched lasers.    
   
   
       24 . The method according to  claim 12 , further comprising: 
 utilizing the activating radiation as a cavity feedback element for laser oscillators.    
   
   
       25 . The method according to  claim 12 , further comprising: 
 utilizing the activating radiation to generate frequency degenerate optical phase-conjugated waves.    
   
   
       26 . The method according to  claim 12 , wherein the multi-photon active medium is selected from the group consisting of a solution of various multi-photon absorbing dye compounds, a proper dye-doped solid rod, film, or waveguide, a multi-photon absorbing neat liquid dye or liquid crystal, and a multi-photon absorbing crystal or semiconductor.