Hollow-core waveguide-based raman systems and methods

Abstract

Embodiments of the invention include a method for sensing. Other embodiments include a method for sensing molecules, for example, homonuclear diatomic molecules. The method may include transmitting light from a light source through a hollow-core wave-guiding device that exhibits a low attenuation at predetermined operating optical frequencies; introducing a gaseous medium between the light source and the hollow-core wave-guiding device; and detecting molecules within the gas.

1 . A method for sensing homonuclear diatomic molecules, comprising:
 transmitting light from a light source through a hollow-core wave-guiding device that exhibits a low attenuation at predetermined operating optical frequencies;   introducing a gaseous medium between the light source and the hollow-core wave-guiding device; and   detecting homonuclear diatomic molecules within the gas.   
   
   
       2 . The method of  claim 1 , wherein said transmitting light comprises transmitting light through a photonic crystal fiber. 
   
   
       3 . The method of  claim 1 , wherein the homonuclear diatomic molecules comprise nitrogen. 
   
   
       4 . A method of detecting comprising:
 transmitting light from a light source through a hollow-core wave-guiding device;   introducing a material between the light source and the hollow-core wave-guiding device; and   detecting a homonuclear diatomic molecule within the material.   
   
   
       5 . The method of  claim 4 , wherein the material comprises one of a flowing liquid, a gaseous medium, and a fluidic medium. 
   
   
       6 . The method of  claim 4 , wherein the material comprises natural gas. 
   
   
       7 . The method of  claim 4 , wherein the homonuclear diatomic molecule comprises nitrogen. 
   
   
       8 . The method of  claim 4 , wherein the hollow-core wave-guiding device comprises a photonic crystal fiber. 
   
   
       9 . The method of  claim 4 , wherein the hollow-core wave-guiding device exhibits a low attenuation at predetermined operating optical frequencies. 
   
   
       10 . The method of  claim 4 , wherein the material comprises air. 
   
   
       11 . A method for optical measurement of at least one analyte in a sample, comprising:
 exciting light into a photonic crystal fiber at excitation conditions that control non-analyte related emission of secondary radiation.   
   
   
       12 . The method of  claim 11 , wherein said emission of secondary radiation is selected from the group consisting of fluorescence emission from material of the photonic crystal fiber, photoluminescence emission from material of the photonic crystal fiber, and Raman emission from material of the photonic crystal fiber. 
   
   
       13 . The method of  claim 11 , wherein said emission of secondary radiation is utilized to improve accuracy of measurements. 
   
   
       14 . The method of  claim 13 , wherein said improvement of accuracy of measurements is provided by corrections for aging of a light source, repositioning effects, or partial contamination of the optical elements. 
   
   
       15 . The method of  claim 13 , wherein said measurements include quantitative analyte determinations 
   
   
       16 . The method of  claim 15 , where said quantitative analyte determinations include univariate analysis or multivariate analysis. 
   
   
       17 . The method of  claim 11 , wherein said emission of secondary radiation is reduced by natural attenuation of the photonic crystal fiber in spectral regions where said emission of secondary radiation occurs. 
   
   
       18 . The method of  claim 17 , wherein detection of optical radiation upon interaction with the sample is accomplished at an excitation end of the photonic crystal fiber. 
   
   
       19 . The method of  claim 17 , wherein detection of optical radiation upon interaction with the sample is accomplished at a distal end of the photonic crystal fiber. 
   
   
       20 . The method of  claim 19 , where an operational lifetime of the photonic crystal fiber is lengthened by a surface treatment to reduce deposition effects of contaminants. 
   
   
       21 . A method for sensing, comprising:
 transmitting light from a light source through a hollow-core wave-guiding device that exhibits a low attenuation at predetermined operating optical frequencies;   introducing a gaseous medium between the light source and the hollow-core wave-guiding device; and   detecting molecules within the gas.   
   
   
       22 . The method of  claim 21 , wherein said transmitting light comprises transmitting light through a photonic crystal fiber.