How to measure the normal light decay of an optical module

Optical losses within a laser cavity/system are inevitable, as are the associated adverse effects on performance metrics (e.g. output power/energy and beam quality). In practical terms, however, a laser system can be built cost-effectively by identifying and specifying only the optical losses critical for system performance and the intended applica. Losses due to scatter are associated with an optic's surface roughness, quality, and figure. Scatter reduces the overall efficiency of laser systems and can lead to premature failures of laser components and/or safety hazards in certain cases (e.g. intracavity use and system alignment). Note that scatter tends to be greater at shorter wavelengthsso. Losses from absorption reduce the optimal laser output and can adversely affect a laser's reliability and lifetime. As the incident laser radiation makes contact with a laser optic, a portion of the radiation is absorbed and is converted into heat. If enough thermal energy accumulates in the optic, it can alter its shape or refractive index (known. Specifying losses related to optical transmission is important when qualifying the performance of components that must transmit light with high efficiency and reliability. Transmission measurements are typically made using spectrophotometers, which use broadband light sources for operation over a wide wavelength range (Figure 2). For improved measu. High-reflectivity mirrors and coatings are essential to the operation of any laser system, especially those designed for beam steering or optimized throughput. These systems commonly require high reflectivities above 99.9%. In laser systems where 99.5% or less reflectivity is acceptable, the common measurement practice is the use of spectrophotomet.