In order to solve the problem of flexible transmission of incident light, optical fiber came into being.
Optical fiber is a kind of light conduction tool made by using the principle of total reflection.
In general photocatalytic experiments, the light source should be facing the reactor window. However, in some specific photocatalytic experiments, it is not convenient for the light source to be placed close to the reactor due to the shape of the reactor and the laboratory space. The light emitted by the light source needs to be shot into the reactor after changing the direction of the optical fiber. In addition, some photocatalytic in-situ tests, such as photocatalytic in-situ diffuse infrared pool, also require light diversion due to the shape of the sample pool and the size of the light window.
There are many kinds of optical fibers, and the corresponding functions and performance are different according to the different materials of optical fibers.
Quartz fiber and liquid core fiber are the most commonly used fibers in the field of photocatalysis.
石英光纤It is made of quartz glass with high purity and has the following characteristics:
（1）High transmittance, quartz fiber is optically transparent over a wide wavelength range, especially in the infrared region;
（2）Mechanical strength, can resist stretching and even bending;
（3）High damage threshold, that is, laser induced breakdown is not easy to occur.
Liquid core optical fiber adopts inorganic salt solution or organic liquid as core material, both ends are sealed with hard transparent materials as optical Windows, and the light is transmitted forward through total reflection in the tube.
Liquid core light has the following characteristics:
（1）Spot homogenization effect is good, no stray spots;
（2）With large numerical aperture, more light energy can be transmitted to ensure the efficiency of light transmission;
（3）Liquid as the core of the fiber has strong selectivity, by choosing different liquids can make it have special functions;
（4）With excellent uv band light transmission capacity, can transmit up to hundreds of watts of high-power light energy, suitable for high-power light source.
The difference between quartz fiber and liquid core fiber
As can be seen from Figure 1, after the xenon lamp source is installed with quartz fiber, the quartz fiber has high transmittance in the ultraviolet, visible and infrared regions ranging from 320 nm to 1050 nm, and the spectral composition changes little. However, there is a specific absorption between 650 nm and 1050 nm in the liquid-core fiber, which results in the attenuation of the optical intensity of the liquid core fiber to some extent.
Figure 1. Spectral comparison of xenon lamp source before and after installing (a) quartz fiber and (b) liquid core fiber
Quartz fiber is recommended for transmission of full-band (320 nm to 1050 nm) or infrared light. Liquid core optical fibers are recommended when the spot uniformity is required and only ultraviolet and visible light are transmitted.
Liquid core fiber can be matched with PLS-SXE 300 xenon lamp, PLS-SXE 300UV xenon lamp, PLS-SXE 300D xenon lamp, PLS-SXE 300DUV xenon lamp and Microsolar 300 Xenon lamp source, PLS-FX300HU high uniformity integrated xenon lamp source, CHF-XM500 mercury lamp source.