Optical absorbance measurement apparatus, method, and applications

摘要

Apparatus and method to measure optical absorption spectra with spatial resolution on the micron scale. An exemplary setup combines a continuous white light excitation beam in transmission geometry with a confocal microscope. Spatial resolution better than 1.4 μm in the lateral and 3.6 μm in the axial, directions was obtained. The detection and measurement of the absorption spectrum of hemoglobin in a single red blood cell under physiological conditions on the timescale of seconds was realized. The apparatus and method enables the investigation of spatial variations in the optical density of small samples on the micron scale and the study of biological assemblies at the single cell level, leading to applications in optical diagnostics, microfluidics, and other areas.

主权项

1. A transmission-geometry, optical absorbance spectroscopy apparatus, comprising:
a broadband sample illumination source providing broadband sample illumination; a broadband sample illumination propagation medium that is an optical waveguide having a proximal end and a distal end; a sample holder; a sample field-of-view controller comprising a sample field-of-view aperture having a maximum dimension less than 50 micrometers (μm) disposed at the distal end of the optical waveguide, which is coupled to the sample holder, wherein the proximal end is coupled to the broadband sample illumination source, wherein the sample field-of-view aperture provides a limiting sample field of view of the broadband sample illumination; and a transmitted light detection path comprising a portion of the broadband sample illumination that is transmitted by the sample.