Reflection Spectrum Analysis Measurement Solution

author: Susan

2022-01-04

Reflection Spectrum Analysis Measurement Solution

Introduction

The two modes of reflection and transmission are the basic methods of spectrum measurement. To achieve these two modes of spectrum measurement, a spectrometer, light source, optical fiber, measurement bracket, standard reference sample, and measurement software are usually required. For different kinds of samples, in order to obtain better spectral data, the two basic modes of reflection and transmission will evolve into more forms.

OPTOSKY has become a user to provide a spectrum measurement equipment with a spectrometer as the core. With these richly configured equipments, various common spectrum measurement systems can be built.
Reflection measurement

Figure 1 Schematic diagram of a typical spectrum measurement system

A spectrum measurement system usually includes components such as spectrometers, light source, optical fiber, sample holder, standard reference sample, and software. Shown in the figure is a typical reflectance spectrum measurement system, the composition of each part is as follows:

1. ATP series spectrometer;

2. Broad-spectrum ultraviolet, visible and near-infrared light sources;

3. 7-core reflective optical fiber;

4. R3, reflection spectrum measurement bracket;

5. Diffuse reflection whiteboard (reflectivity ≥98%);

6. Spectral measurement software.

Each component of the spectrum has its spectral range. Therefore, it is necessary to select a suitable spectral range according to the actual needs of users. For example, in order to measure the spectrum of the ultraviolet part, it is necessary to use an ultraviolet-sensitized spectrometer capable of detecting the ultraviolet band and a wideband light source with ultraviolet radiation.

The two basic measurement modes of reflection and transmission are introduced below.

Figure 2 Three typical emission spectrum measurement methods

The reflection on the surface of an object mainly includes specular reflection and diffuse reflection. The reflection of light on a perfectly flat surface is specular reflection. The reflection of light on a rough surface is diffuse reflection. The reflection of light on the surface of most objects is somewhere in between.

For specular reflection, a reflective fiber is generally used to measure incidence at 0 degrees and reflection at 0 degrees. For diffuse reflection, the integrating sphere is generally used for measurement. In addition, specular reflection can also be measured by incident at 45 degrees and reflection at 45 degrees; diffuse reflection can also be measured by incident at 0 degrees and reflection at 45 degrees. It depends on the sample and the measurement standard used.

As shown in the figure above, the blue frame is the basic specular reflection spectrum measurement method. The Y-shaped reflective fiber is used in the measurement.

The red frame is an inverted specular reflection spectrum measurement method. Because this method can keep the distance from the sample to the reflective fiber exactly equal to the distance from the standard reference sample to the reflective fiber, the inverted spectrum measurement method is more suitable for occasions that require precise measurement of spectral reflectance.

The green frame is an inverted integrating sphere reflection spectrum measurement method, which can be illuminated at an angle of 8 degrees and accepted at a 90 degree angle, or can be illuminated at an angle of 90 degrees and accepted at an 8 degree angle. This method is suitable for the reflectance measurement of rough or suede samples.

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