To ensure reliability and safety, the developers of medical equipment that use laser technology know they need to be careful when they select the optical components. High power density and narrow wavelength range lasers bring with them problems that are not always found in other optical design. Choosing the correct materials, designing exact manufacturing specifications and using proper coatings are essential to avoiding issues with the lasers when they’re put into use in a patient setting.
Material selection is one of the first items a designer chooses when developing medical laser components. Using typical high power substrate for lenses and windows, one of the preferred materials is calcium fluoride because it provides high transmission from the ultraviolet through the infrared wavelengths. Calcium fluoride has a low index of refraction and in many cases it can be utilized without additional applications of coatings.
Following the choice of substrate, the designer specifies the manufacturing parameters with the key one being surface quality. Even a small imperfection on the surface can lead to the scattering of light and potentially dangerous outcomes. Optics for eye surgery, for example, have to precisely administer appropriate amounts of energy through the laser without causing injury to the patient’s eye. If the energy scatters because of an imperfection, it results in unreliable energy delivery and the potential for injury. Even though designers understand that optical surfaces are never perfect, defects such as marks, tears or scratches need to be minimized in the selection process.
A defect in the coating on the lens can also lead to energy absorption or cracking in the optics and that could lead to a catastrophic system failure. The application of the correct coating greatly improves the behavior and results of the laser system.
When choosing a coating for the lens used in a laser system, the developers have to take into consideration the range of the source’s power and then choose a coating that will perform at the thresholds required. In a laser system, the optical coating is typically what fails.
Universe Kogaku designs and manufactures optical lenses for industrial, medical, high tech and electronic applications. Standard and custom lens assemblies are also available for scanners, CCTV, CCD/CMOS, medical imaging, surveillance systems, machine vision and night vision systems