Axial Illumination for Capillary Electrophoresis
System and method for fluorescent light excitation and detection from samples to enhance the numerical aperture and/or reduce the cross-talk of the fluorescent light.
1 . An excitation system for analyzing samples comprising:
a non-coherent light source;
a housing, wherein the housing transports samples and propagates light from the non-coherent light source by total internal reflection; and
a coupling optical element configured to introduce light from the non-coherent light source into the housing through a wall of the housing.
2 . The system of claim 1 , wherein the housing comprises a plurality of capillaries.
3 . The system of claim 1 , further comprising a second coupling optical element.
4 . The system of claim 3 , further comprising a second non-coherent light source, and
wherein the housing comprises a detection zone disposed between the coupling optical element and the second coupling optical element.
5 . The system of claim 3 , wherein at least one of the coupling optical elements comprises a truncated sphere.
6 . The system of claim 5 , wherein the truncated sphere comprises;
a coupling section joined to a portion of the housing;
a lens section joined to a first portion of the coupling section; and
a second lens section joined to a second portion of the coupling section.
7 . The system of claim 3 , wherein at least one of the coupling optical elements comprises a conical shaped element.
8 . The system of claim 7 , wherein a cone angle of the conical shaped element is within a range of angles in which light can enter the housing and propagate by total internal reflection.
9 . The system of claim 1 , further comprising a light dump configured to allow light to escape from the housing.
10 . The system of claim 1 , wherein the light dump is at least one of a black paint, an epoxy, a charred polyimide, a curved section of the housing, and a optical element having an index of refraction equal to or greater than an index of refraction of the housing.
11 . The system of claim 1 , wherein an index of refraction of the coupling optical element is greater than an index of refraction of the housing.
12 . A fluorescence excitation system for analyzing samples comprising:
a non-coherent light source;
a housing, wherein the housing transports the samples and propagates light from the non-coherent light source; and
at least one high NA optical element configured to focus light from the non-coherent light source onto an end of the housing.
13 . The system of claim 12 , wherein the at least one high NA optical element comprises a truncated sphere.
14 . The system of claim 12 , wherein the at least one high NA optical element comprises a meniscus lens.
15 . The system of claim 12 , wherein the housing comprises a capillary and a fluid within the capillary, wherein the fluid has an index of refraction greater than an index outside of the housing.
16 . The system of claim 12 , wherein the housing further comprises a detection zone axially illuminated by light introduced into the end of the housing.
17 . The system of claim 12 further comprising a light dump configured to allow light to escape from the waveguide after passing through the detection zone.
18 . The system of claim 12 , wherein the housing comprises a plurality of capillaries.
19 . A method for exciting fluorescence of samples comprising:
transporting a plurality of samples through a detection zone with a capillary;
directing a non-coherent light into the capillary with a coupling optical element; and
illuminating the detection zone with the non-coherent light propagating through the capillary.
20 . The method of claim 19 , wherein said directing a non-coherent light into the capillary with a coupling optical element comprises focusing the non-coherent light onto an end of the capillary with at least one of a truncated sphere and a meniscus lens.
21 . The method of claim 19 , wherein said directing a non-coherent light into the capillary with a coupling optical element comprises focusing the non-coherent light through a wall of the capillary with at least one of a truncated sphere and a conical shaped element.
22 . The method of claim 19 , wherein said directing a non-coherent light into the capillary with a coupling optical element comprises focusing the non-coherent light through a wall of the capillary with an excitation lens comprising a coupling section joined to the capillary and at least one lens portion joined to the coupling section.
23 . The method of claim 19 , further comprising directing the non-coherent light into the capillary with a second coupling optical element.
24 . The method of claim 23 , wherein the coupling optical element directs the non-coherent light to propagate through the detection zone along a first direction and the second coupling optical element directs the non-coherent light to propagate through the detection zone along a second direction.
25 . The method of claim 19 , further comprising removing the non-coherent light from the housing after the non-coherent light passes through the detection zone.
26 . The method of claim 19 , wherein the plurality of samples are transported through the detection zone by a fluid having an index of refraction lower than an index of refraction of a material comprising the capillary.
27 . A system for analyzing samples comprising:
a light source that provides a non-coherent excitation light;
at least one housing, wherein the housing transports samples and propagates the non-coherent excitation light by total internal reflection;
a coupling optical element configured to introduce the non-coherent excitation light into the at least one housing through a wall of the at least one housing; and
at least one NA enhancing optical element to collect an emitted fluorescence,
wherein the NA enhancing optical element is constructed of a first material and the housing is constructed of a second material, wherein the first material has a greater index of refraction than the second material.
28 . The system of claim 27 , further comprising:
a mask comprising at least one aperture adapted to reduce cross-talk of fluorescent light from the samples; and
a translation mechanism, wherein the translation mechanism is adapted to move at least one of the NA enhancing optical element, the at least one housing, and the mask.
29 . The system of claim 28 , wherein the NA enhancing optical element is a truncated sphere.
30 . The system of claim 28 , further comprising a second coupling optical element and a second non-coherent light source.
31 . The system of claim 30 , wherein at least one of the coupling optical element and the second coupling optical element comprises a truncated sphere.
32 . The system of claim 31 , wherein the truncated sphere comprises;
a coupling section joined to a potion of the at least one housing;
a lens section joined to a top of the coupling section; and
a second lens section joined to a bottom of the coupling section.
33 . The system of claim 30 , wherein at least one of the coupling optical element and the second coupling optical element comprises a conical shaped element.
34 . The system of claim 27 , further comprising a plurality of housings.
35 . The system of claim 34 , further comprising a detector adapted to detect fluorescent light from multiple housings per cycle
36 . The system of claim 34 , further comprising a detector adapted to detect fluorescent light from one housing per cycle.
37 . A system for analyzing samples comprising:
a light source that provides a non-coherent excitation light;
at least one housing, wherein the housing transports samples and propagates the non-coherent excitation light by total internal reflection;
a coupling optical element configured to introduce the non-coherent excitation light into the at least one housing through a wall of the at least one housing; and
at least one NA enhancing optical element to collect an emitted fluorescence,
wherein the NA enhancing optical element is constructed of a first material and the housing is constructed of a second material, wherein the first material has a greater index of refraction than the second material.