Miniature multiple wavelength excitation and emission optical system and method for laser-induced fluorescence detectors in capillary electrophoresis

An optical system for optical detection utilizing a capillary flow cell containing a sample, the optical instrument comprising:

• a. an optical apparatus comprising a concave reflector with an optical axis positioned at one side of said flow cell, a lens collector positioned at an opposite side of said flow cell, and means positioned at close proximity of said flow cell for delivery of an excitation light along a direction in a plane orthogonal to said optical axis to cause said sample to emit emission lights;
• wherein said reflector having a concave surface for reflecting said emission lights;
• and
• said collector having a proximal convex surface for collecting said emission lights, and a distal convex surface for collimating said emission lights;
• and
• b. means for detection of said collimated emission lights.

A method of improving collection efficiency in an optical instrument for optical detection utilizing a capillary flow cell to contain a sample, the method comprising the steps of:

• a. positioning a concave reflector with an optical axis having a concave surface at one side of said flow cell for said concave surface to reflect emission lights emitted by the sample;
• b. positioning a lens collector having a proximal convex surface and a distal convex surface at an opposite side of said flow cell for said proximal convex surface to collect said emission lights and for said distal convex surface to collimate said emission lights;
• c. delivering an excitation light at a close proximity of said flow cell along a direction in a plane orthogonal to said optical axis to cause said sample to emit said emission lights;
• and
• d. detecting said collimated emission lights.