| 摘要 |
The invention concerns measurements in which light interacts with matter giving rise to changes in light intensity, and preferred embodiment spectrophotometer devices of the invention provide for ultrasensitive measurements through a reflection interaction with matter. The level of light source noise in these measurements can be reduced in accordance with the invention. Preferred embodiments of the invention use sealed housings lacking an internal light source, and reflection based sample and reference cells. In some embodiments a substantially solid thermally conductive housing is used. Other features of preferred embodiments include particular reflection based sample and reference cells. A total internal reflection embodiment includes, for example, a prism including an interaction surface, a detector, a lens that focuses a beam output from the prism onto the detector, and a closed interaction volume having an inlet and an outlet for delivering gas or liquid to the interaction surface. In a specular reflection embodiment, a reflective surface is used instead of a prism. In a diffuse reflection embodiment a matte surface is used instead of a prism and the matte surface produces scattering. Aspects of the invention include identification of noise-contributing components in spectrophotometry and the select set of preferred features in a given embodiment, and noise levels very near the shot noise limit may be realized with application of preferred embodiment devices.
|
