Apparatus for conducting Raman spectroscopy using fiber optics

Abstract

A fiber optic probe apparatus useful for conducting Raman spectroscopy remotely over optical fibers with minimal interference from Raman scattering within said fibers which includes three elements. The first element is at least one transmitting optical fiber having a first end and a second end. The second element is at least one collecting optical fiber for collecting light from a sample positioned near the first end of the transmitting optical fiber, the collecting optical fiber having a first end and a second end, the first end of the collecting optical fiber being in closely spaced relationship with the first end of the transmitting optical fiber wherein the longitudinal axis of the first end of the collecting optical fiber converges with the longitudinal axis of the first end of the transmitting optical fiber at an angle of less than forty five degrees. The third element is at the heart of the invention. The third element is a rejection optical filter in optical communication with the second end of the collecting optical fiber.

What is claimed is:  
     
       1. A fiber optic probe apparatus useful for conducting Raman spectroscopy remotely over optical fibers with minimal interference from Raman scatering within said fibers, comprising: 
       (a) at least one transmitting optical fiber for transmitting light, the transmitting optical fiber having a first end and a second end;  
       (b) at least one collecting optical fiber for collecting light from a turbid liquid or solid sample positioned near the first end of the transmitting optical fiber, the collecting optical fiber having a first end and a second end, the first end of the collecting optical fiber being in closely spaced relationship with the first end of the transmitting optical fiber wherein the longitudinal axis of the first end of the collecting optical fiber converges with the longitudinal axis of the first end of the transmitting optical fiber at an angle of less than forty five degrees;  
       (c) a rejection optical filter adapted to filter out a laser line, the rejection optical fiber in optical communication with the second end of the collecting optical fiber.  
     
     
       2. The apparatus of claim  1 , further comprising: 
       d) a sending optical fiber having a first end and a second end, the second end of the sending optical fiber being in optical communication with the second end of the transmitting optical fiber;  
       e) a light source for directing light into the first end of the sending optical fiber so that the light can emerge from the first end of the transmitting optical fiber onto a sample particle positioned near the first end of the transmitting optical fiber;  
       f) a detector optical fiber having a first end and a second end, the first end of the detector optical fiber being in optical communication with the rejection optical filter;  
       g) a light detector in optical communication with the second end of the detector optical fiber so that light from the sample partical can travel along the collecting optical fiber, be filtered by the rejection optical filter and then be detected by the light detector.  
     
     
       3. The apparatus of claim  1 , further comprising: 
       (d) a bandpass optical filter, the bandpass optical filter being in optical communication with the second end of the transmitting optical fiber.  
     
     
       4. The apparatus of claim  1 , further comprising: 
       (e) a sending optical fiber having a first end and a second end, the second end of the sending optical fiber being in optical communication with the bandpass optical filter and the second end of the transmitting optical fiber, so that light traveling from the sending optical fiber can be filtered by the bandpass filter and directed into the second end of the transmitting optical fiber;  
       (f) a light source for directing light into the first end of the sending optical fiber so that the light can emerge from the first end of the transmitting optical fiber onto a sample particle positioned near the first end of the transmitting optical fiber;  
       (g) a detector optical fiber having a first end and a second end, the first end of the detector optical fiber being in optical communication with the rejection optical filter;  
       (h) a light detector in optical communication with the second end of the detector optical fiber so that light from the sample particle can travel along the collecting optical fiber, be filtered by the rejection optical filter and then be detected by the light detector.