Transmission spectra is a research area within the field of spectroscopy that focuses on studying the wavelengths of light that are transmitted through a sample. By analyzing the transmission spectra of a material, researchers can gain insights into its optical properties, such as absorbance, reflectance, and refractive index. This information can be used to identify the composition, structure, and chemical properties of the material. Transmission spectra are typically obtained by passing light through a sample and measuring the intensity of the transmitted light at different wavelengths. This technique is commonly used in fields such as chemistry, physics, biology, and material science for a variety of applications, including identifying unknown substances, monitoring chemical reactions, and studying the behavior of materials under different conditions.