Light is the origin of life, the tool of human understanding the outside world and a perfect carrier or propagating media of information. It is widely used from our daily lives to the industrial production. The typical applications include fabrication, imaging and sensing. Especially, the laser makes the light have higher coherence, higher beam quality and higher intensity since its invention in 1960s. Hence, the laser can be applied as an advanced tool for fabrication in industry and research. It can generate functional structures from nanometer scale to macroscopic. However, there are still plenty of challenges in applications. In this issue, we provide a review on the development and challenges of liquid-assisted laser machining and two articles on the new methods to solve the problems in materials for the two-photons polymerization and the optimization of stainless steel patterning. According to the statistics, more than 80% information collected by the sensory organs of human comes from the eyes. The eyes are fantastic optical imaging systems in nature. The imaging techniques are widely used from photography to security check. Although the camera with the high resolution and high sensitivity is developed, it still cannot satisfy the requirement in some special cases without image processing, such as the signal collection with low signal-noise ratio and three dimensional imaging. The information is hard to be collected without imaging processing by algorithm. Hence, the advanced methods and algorithms are highly required for image processing. In this issue, five articles will report the advanced algorithms and system setups from target reorganization, background suppression and 3D reconstruction. Sensing is quite important in the areas of biomedical science, security and automatic control. Compared with other sensing techniques, light has great advantages in nondestructive examination with high sensitivity. The design and optimization of the hardware for sensing is always developing. Two papers on a novel sensor based on THz metamateiral and solar-blind avalanche photodiodes with low breakdown voltage are included in this issue.