Scanning Spectrophotometer for high throughput fluorescence detection and fluorescence polarization

A double monochromator comprising:

• an entrance aperture for accepting input light;
• a first optical grating positioned to disperse at least part of the light accepted through the entrance aperture;
• a first selection aperture positioned to intercept part of the light dispersed by the first optical grating and operative to pass a selected range of wavelengths of the dispersed light;
• a second optical grating positioned to disperse at least part of the light passed through the first selection aperture;
• and
• a second selection aperture positioned to intercept part of the light dispersed by the second optical grating and operative to pass a selected range of wavelengths of the dispersed light as output light;
• wherein each of the first optical grating and the second optical grating is operative to pivot about a respective axis of rotation allowing selection of a range of wavelengths of light to be passed through the first selection aperture and the second selection aperture, respectively, as a function of rotation angle;
• the double monochromator further comprising means for pivoting the first optical grating about its respective axis of rotation and pivoting the second optical grating about its respective axis of rotation synchronously;
• and wherein the means for pivoting comprises a band drive mechanism operatively coupled to each of the first optical grating and the second optical grating.

A light transfer module comprising:

• an excitation mirror operative to direct incoming light to illuminate an area such that the illuminated area emits fluorescent or luminescent light;
• an emission mirror operative to focus and to direct light emitted by the illuminated area as emission light;
• an optical filter operative to restrict the incoming light to a selected polarized plane;
• and
• an optical filter holder selectively operative to insert the optical filter into the path of the incoming light, wherein the excitation mirror, the emission mirror and the illuminated area are substantially centered along a common axis.

A spectrophotometer system comprising:

• a light source comprising a spherical concave reflector system;
• the reflector system being telecentric at both ends and fully corrected for third order aberrations;
• a first multiple-grating monochromator having an entrance aperture;
• the first multiple-grating monochromator being operative to separate light imaged onto the entrance aperture from the light source into a plurality of wavelengths and to output selected wavelengths as excitation light;
• a light transfer module comprising:
• a first reflection surface operative to direct substantially all of the excitation light directly onto a sample;
• and
• a second reflection surface in alignment with the first reflection surface;
• the second reflection surface being a compound parabolic reflective surface and operative to collect and to direct light emitted from the sample as fluorescent or luminescent light, wherein the first reflection surface, the second reflection surface and an area to be illuminated are centered on a common axis;
• a second multiple-grating monochromator operative to separate the fluorescent or luminescent light into a plurality of wavelengths and to output selected wavelengths of the fluorescent or luminescent light as emission light;
• and
• a photodetector and analyzer, operative to receive the emission light output by the second multiple-grating monochromator, to detect the selected wavelengths of the emission light, and to output an indication of the selected wavelengths.

A light transfer module comprising:

• an entrance aperture for admitting excitation light;
• an excitation mirror operative to direct excitation light from the entrance aperture to illuminate an area such that the illuminated area emits fluorescent or luminescent light;
• and
• a compound parabolic concentrator comprising a compound parabolic reflective surface and operative to collect and to direct light emitted from the illuminated area to an emission mirror, wherein the excitation mirror, the compound parabolic concentrator and illuminated area are substantially centered along a common axis.

A method of analyzing a sample comprising:

• providing excitation light from a light source;
• directing the excitation light through a first double monochromator;
• transmitting the excitation light to the sample through a light transfer module;
• selectively analyzing polarization of the light emitted by the sample;
• employing the light transfer module to obtain light emitted by the sample;
• directing the light emitted by the sample to a second double monochromator;
• and
• analyzing light output by the second double monochromator, wherein
• the light transfer module comprises first and second reflection surfaces substantially centered on a common axis with the sample, and wherein the transmitting includes redirecting the excitation light received at the first reflection surface onto the sample and wherein the directing the emitted light includes redirecting emitted light received at the second reflection surface onto the second double monochromator.