Laser magneto-optic rotation spectrometer (LMORS)

Abstract

A magneto-optical rotation (MOR) spectrometer is disclosed having a laser as a light source and providing a high intensity input light source that yields improvements in the detection limits and in the dynamic operating ranges of the MOR spectrometer.

What we claim is: 
     
       1. A spectrometer for measuring the concentration of atoms and molecules of a substance comprising: (a) means for atomizing said substance in a chamber;   (b) magnetic means providing a continuous magnetic field and surrounding said atomized substance but leaving a passageway having entrance and exit portions into and from said chamber;   (c) first and second stationary optical polarizers respectively located at said entrance and exit portions of said passageway;   (d) a laser source having a predetermined intensity and comprising collimated light rays focused into a path so as to pass through said first optical polarizer, into and out of said chamber and then pass through said second optical polarizer; and   (e) an optical detector for detecting the intensity of the rays of said laser after said laser rays pass through said second optical polarizer and providing a representative output signal thereof.   
     
     
       2. The spectrometer according to claim 1 further comprising: (a) a modulator interposed between said laser source and said first polarizer and intercepting said rays of said laser and providing a modulated light output to said first optical polarizer and a modulated electrical signal output; and   (b) a lock-in amplifier having a balanced amplifier with two branches with the first branch receiving said output of said optical detector and a second branch receiving said modulated electrical signal.   
     
     
       3. The spectrometer according to claim 2, wherein said laser source has an operating wavelength in the range from about 200 nm to about 900 nm. 
     
     
       4. The spectrometer according to claim 1, wherein said magnetic means comprises an electromagnet that generates a magnetic field of up to about 10 KG. 
     
     
       5. The spectrometer according to claim 1, wherein said substance is atomized by aspiration. 
     
     
       6. The spectrometer according to claim 1, wherein said means for atomizing is selected from the group consisting of a graphite furnace, cold vapor generation and laser induced breakdown. 
     
     
       7. The spectrometer according to claim 1, wherein said laser source comprises: (a) a Nd:YAG source that generates collimated light rays at a first predetermined operating wavelength;   (b) a first frequency doubler having an output and that receives the light rays of said Nd:YAG source and generates collimated light rays at a second predetermined operating wavelength which is about one-half of said first predetermined operating wavelength;   (c) a dye laser for generating tuneable light and that receives the output of said first frequency doubler and generates collimated light rays at a third predetermined operating wavelength; and   (d) a second frequency doubler having an output serving as the output of said laser source and that receives the tuneable light of said dye laser and generates collimated light rays at a fourth predetermined frequency which is about one-half of said third predetermined operating wavelength.   
     
     
       8. The spectrometer according to claim 7, wherein said magnetic means comprises a permanent magnet that generates a magnetic field of up to about 4 KG.