 Optical approaches in the new infrared or NIR window offer great advantages over traditional techniques such as magnetic resonance imaging or MRI. These advantages include deeper tissue penetration, lower scattering and absorption, and higher resolution. This makes them ideal for studying the inner workings of the brain from its structure to its chemical composition. Recent advances in NIR light technology have enabled researchers to image and manipulate brain activity at unprecedented depths. This has led to new insights into how the brain works and how it can be manipulated to treat various conditions. This article was authored by Hong Yang Yin, Wukia Jiang, Yongyang Liu, and others.