Surface plasmon resonance spectrometer with an actuator driven angle scanning mechanism

Abstract

Instruments and methods relating to surface plasmon imaging are described. An instrument comprises a semi-circular rail and a driving mechanism. The driving mechanism is attached to a light source mount and a detector mount, and both the light source mount and the detector mount are attached to the semi-circular rail with connectors. Each connector allows the light source mount and detector mount to slide along the rail. The synchronous movement of the light source mount and the detector mount changes the angle of incidence of a light beam from the light source with respect to the plane of the sample surface on the sample stage.

1 . An instrument comprising:
 a rail, where the rail traverses a portion of the perimeter of a circle;   a slidable light source associated with the rail;   a swing arm to locate the position of the light source on the rail;   a sample stage forming a plane adapted to generate surface plasmons when irradiated by the light source;   a slidable detector associated with the rail adapted to detect changes in light intensity; and   a linear actuator to adjust the position of the light source and the detector to an optimum optical pass configuration, where the position of the light source and the position of the detector are moved synchronously in opposite directions along the rail to the optimum optical pass configuration.   
     
     
         2 . The instrument of  claim 1 , where the angle of incidence of the light source on the sample stage is varied to determine the optimum optical pass configuration. 
     
     
         3 . The instrument of  claim 1 , where the optimum optical pass configuration is chosen such that light from the source directed at the sample stage is optimally reflected at an angle less than the critical angle to generate surface plasmons. 
     
     
         4 . The instrument of  claim 1 , where the optimum optical pass configuration is based at least in part on the effective refractive index of the sample stage. 
     
     
         5 . The instrument of  claim 1 , further comprising a micromirror located at one or both the sample stage and the detector. 
     
     
         6 . The instrument of  claim 1 , further comprising a telescope tube located at the detector. 
     
     
         7 . The instrument of  claim 1 , where the detector is a CCD camera. 
     
     
         8 . The instrument of  claim 1 , where the sample stage is positioned roughly perpendicular to the plane of the rail. 
     
     
         9 . The instrument of  claim 1 , where the light source is a laser. 
     
     
         10 . The instrument of  claim 9 , further comprising a rotating mirror assembly to scan the laser. 
     
     
         11 . The instrument of  claim 1 , further comprising a prism positioned to alter the light emitted by the light source. 
     
     
         12 . The instrument of  claim 11 , where the optimum optical pass configuration is based at least in part on optimizing the refractive index at the wavelength of the light of the prism. 
     
     
         13 . The instrument of  claim 11 , where the prism and the sample stage are made of materials with similar refractive indices. 
     
     
         14 . The instrument of  claim 11 , where the prism and the sample stage are coupled to each other with an index-matching substance. 
     
     
         15 . The instrument of  claim 11 , where light from the light source passes through one face of the prism, passes through the prism and is reflected off the sample surface coupled to the prism, exits the third face of the prism and impinges on the detector. 
     
     
         16 . The instrument of  claim 1 , further comprising one or more light polarizers positioned to alter the light emitted by the light source. 
     
     
         17 . The instrument of  claim 1 , further comprising one or more wave plates positioned to alter the light emitted by the light source. 
     
     
         18 . An instrument comprising:
 a rail, where the rail traverses a portion of the perimeter of a circle;   a slidable light source associated with the rail;   a first swing arm to locate the position of the light source on the rail;   a sample stage forming a plane adapted to generate surface plasmons when irradiated by the light source;   a slidable detector adapted to detect changes in light intensity associated with the rail;   a second swing arm to locate the position of the slidable detector on the rail; and   a linear actuator to adjust the position of the light source and the slidable detector to an optimum optical pass configuration, where the first and second swing arms are connected to the linear actuator, where the position of the light source and the position of the detector are moved synchronously in opposite directions along the rail to the optimum optical pass configuration.   
     
     
         19 . The instrument of  claim 17 , where one or both the first and second swing arms are curved. 
     
     
         20 . An instrument comprising:
 a rail, where the rail traverses a portion of the perimeter of a circle;   a light emitting diode (LED) associated with the rail;   a swing arm to locate the position of the LED on the rail;   a sample stage adapted to generate surface plasmons when irradiated by the LED;   a slidable detector associated with the rail adapted to detect changes in light intensity; and   a linear actuator to adjust the position of the LED and the slidable detector to an optimum optical pass configuration, where the position of the LED and the position of the detector are moved synchronously in opposite directions along the rail to the optimum optical pass configuration.