Flow cytometry optics

A particle analyzer comprising:

• an ellipsoidal reflector having a shape characterized by lengths of major and minor axes of a defining ellipse and having conjugate foci F1 and F2 located on the major axis, with F1 in a flow path for a stream of particles;
• one or more light sources configured to provide one or more excitation light beams directed to intersect the stream of particles at or approximately at F1 , thereby exciting fluorescence from the particles;
• and
• a spherical reflector having its center of curvature coincident or approximately coincident with F1;
• wherein at least a portion of fluorescence emitted toward the ellipsoidal reflector is focused by the ellipsoidal reflector to one or more locations at or near F2, at least a portion of fluorescence emitted toward the spherical reflector is retro-reflected by the spherical reflector toward the ellipsoidal reflector which focuses the retro-reflected fluorescence to the one or more locations at or near F2, the radius of curvature of the spherical reflector is less than the distance between F1 and F2, and the ellipsoidal reflector focuses fluorescence incident on it through the spherical reflector to F2 beyond the spherical reflector.

A particle analyzer comprising:

• an ellipsoidal reflector having a shape characterized by lengths of major and minor axes of a defining ellipse and having conjugate foci F1 and F2 located on the major axis, with F1 in a flow path for a stream of particles;
• one or more light sources configured to provide one or more excitation light beams directed to intersect the stream of particles at or approximately at F1, thereby exciting fluorescence from the particles;
• and
• a spherical reflector having its center of curvature coincident or approximately coincident with F1;
• wherein at least a portion of fluorescence emitted toward the ellipsoidal reflector is focused by the ellipsoidal reflector to one or more locations at or near F2, at least a portion of fluorescence emitted toward the spherical reflector is retro-reflected by the spherical reflector toward the ellipsoidal reflector which focuses the retro-reflected fluorescence to the one or more locations at or near F2, and the ratio of the major and minor axes of the ellipse defining the shape of the ellipsoidal reflector is greater than or equal to about 1.4.