Dual wavelength optical analyser

Abstract

An optical device for directing optical signals in a fluorescence-based analyser having first and second laser light sources for providing illuminating laser light at different wavelengths. The device comprises a band pass laser filter associated with each laser and arranged to allow laser light of the relevant wavelength of its associated laser to pass therethrough but to reflect light of other wavelengths, each band pass filter being arranged to direct laser light from both of the lasers into a single path directed at a sample to be illuminated in use. At least two fluorescence band pass filters are provided, each of which is arranged to allow light of a selected fluorescent wavelength therethrough. The laser band pass filters are arranged to reflect flourescent light received from the sample towards the fluorescence filters such that, in use, light received from the sample is allowed to pass through a first of the fluorescence filters if it is at a first wavelength, and through the second of the fluorescence filters if it is at a second wavelength to provide an output signals for analysis at the output of each of the fluorescence filters.

1 . An optical device for directing optical signals in a fluorescence-based analyser having first and second laser light sources for providing illuminating laser light at different wavelengths, the device comprising: 
 a band pass laser filter associated with each laser and arranged to allow laser light of the relevant wavelength of its associated laser to pass therethrough and to reflect light of other wavelengths, each band pass filter being arranged to direct laser light from both of the lasers into a single path directed at a sample to be illuminated in use; and    at least two fluorescence band pass filters, each of which is arranged to allow light of a selected fluorescent wavelength therethrough;    wherein the laser band pass filters are arranged to reflect fluorescent light received from the sample towards the fluorescence filters such that, in use, light received from the sample is allowed to pass through a first of the fluorescence filters if it is at a first wavelength, and through the second of the fluorescence filters if it is at a second wavelength to provide corresponding output signals for analysis at the output of each of the fluorescence filters.    
     
     
         2 . A device according to  claim 1 , further comprising a scatter filter for filtering out back-scattered laser light.  
     
     
         3 . A device according to  claim 2 , wherein the output of the one of the laser filters or the scatter filter is used to provide a monitoring signal.  
     
     
         4 . A device according to  claim 3 , wherein the monitoring signal is fed to a focussing device associated with the output of the device to provide control thereto.  
     
     
         5 . A device according to  claim 3 , wherein the monitoring signal is fed to a processor which analyses the monitoring signal to provide an output indicative of a bar code that is scanned by at least one of the laser light beams in use.  
     
     
         6 . A device according to  claim 1 , wherein one or more additional filters are positioned at the output of one or more of the fluorescent filters in order to reduce the amount of interference from back scattered illuminating light that may pass therethrough.  
     
     
         7 . A device according to  claim 1 , further comprising one or more optical fibres positioned in the light path through which the laser light passes and returned fluorescent light is received.  
     
     
         8 . A fluorescent-based analyser comprising: 
 a first and a second laser light source arranged to emit laser light at differing wavelengths;    a band pass laser filter associated with each laser and arranged to allow laser light of the relevant wavelength of its associated laser to pass therethrough and to reflect light of other wavelengths, each band pass filter being arranged to direct laser light from both of the lasers into a single path directed at a sample to be illuminated in use; and    at least two fluorescence band pass filters, each of which is arranged to allow light of a selected fluorescent wavelength therethrough;    wherein the laser band pass filters are arranged to reflect fluorescent light received from the sample towards the fluorescence filters such that, in use, light received from the sample is allowed to pass through a first of the fluorescence filters if it is at a first wavelength, and through the second of the fluorescence filters if it is at a second wavelength to provide an output signals for analysis at the output of each of the fluorescence filters coupled to the laser lighht sources; and    analysing means associated with the outputs of each of the fluorescence filters to provide fluorescence data based thereon.    
     
     
         9 . An analyser according to  claim 8 , further comprising means of monitoring the power of laser light introduced, in use, to the optical device, and means for comparing said laser light with received fluorescent light levels.  
     
     
         10 . A device according to  claim 8 , arranged to separate multiwavelength images from a single composite target according to their individual wavelengths.  
     
     
         11 . An optical receiver for directing optical signals received from a fluorescence-based analyser, the device comprising: 
 at least two fluorescence band pass filters, each of which is arranged to allow light of a selected fluorescent wavelength therethrough; and    means for directing light towards the fluorescence band pass filters such that, in use, light received the fluorescence-based analyser is allowed to pass through a first of the fluorescence filters if it is at a first wavelength, and through the second of the fluorescence filters if it is at a second wavelength to provide output signals for analysis at the output of each of the fluorescence filters.    
     
     
         12 . A device according to  claim 11 , wherein one or more additional filters are positioned at the output of one or more of the fluorescent filters in order to reduce the amount of interference from back scattered illuminating light that may pass therethrough.  
     
     
         13 . A device according to  claim 11 , further comprising one or more optical fibres positioned in the light path through which fluorescent light is received.  
     
     
         14 . An analyser according to  claim 8  further comprising means for focussing the output laser light, in use, on a sample; and 
 means for generating relative motion between the scanning light and the sample to be scanned in use.