The latest issue of the Journal of the Optical Society of America published the research results of mid-infrared fiber gas laser pointer by researchers at the University of Bath in the United Kingdom. Mid-infrared lasers of 3.1 to 3.1 microns have important uses in special applications such as spectroscopy, environmental monitoring, and explosive detection, but lasers in this field have not been easy to manufacture.
University scientists put suitable gas into the hollow fiber to realize mid-infrared laser radiation, combining mid-infrared wavelength and fiber laser’s stable, convenient, high-quality, and high-power output characteristics. One of the leaders of the project, traditional fiber lasers are not easy to maintain high power above 2.8 microns, and other similar quantum cascade lasers do not support laser wavelengths below 3.5 microns.
Using the multi-core hollow fiber made of silica material they developed, this problem was solved. Comparing their multi-core optical fiber structure to a series of glass tubes, light is restricted to transmit in the hollow core by the reflection of these glass tubes, instead of transmitting in the glass core as in ordinary optical fibers. It is this characteristic that guarantees that this kind of optical fiber does not have the problem of absorption of wavelengths above 2.8 microns like ordinary optical fibers. The advantage of hollow optical fiber is that the transmission intermediate distance is long enough. In this example, they used 10 meters to 11 meters of hollow fiber, which is acetylene gas.
Researchers at the university did not first think of filling the optical fiber with a specific gas. Similar designs have also been available before. Their idea is to add a piece of feedback fiber to form a reflective cavity. The reflection section amplifies a part of the output light, thereby reducing the demand for pump power. In this design, mature semiconductor green laser pointer for communications are used. This laser is practical enough, cheap enough, and powerful enough.
Fei Yu, a Chinese scholar on the team, said that they have developed a laser wavelength that uses light to pump molecules and generate laser wavelengths that are not easily generated by traditional techniques. This combination of gas and fiber technology can be used to develop more types of lasers. Different gases, lasers up to 5 microns can also be produced using this technology.