Dielectric coatings are one of our core competencies at Laser Components. We primarily deposit customer-specific optical coatings onto almost any substrates. E-beam technology, also referred to as physical vapor deposition (PVD), ion-assisted deposition (IAD), and ion beam sputtering (IBS) are the coating processes currently available.
The degree of reflection slopes from the center of the optic in a Gaussian distribution. Used in unstable resonators.
Gaussian mirrors, also known as VRM (variable reflecting mirrors), are characterized by a degree of reflection that slopes from the center of the optic in a Gaussian distribution. LASER COMPONENTS is one of the few manufacturers worldwide that offers this special type of mirror.
The mirrors are used in unstable resonators where they help produce high quality laser beams with low beam divergence at high pulse energies. In frequency-doubled systems they are used to achieve a greater pump efficiency. The Gaussian mirrors are extremely stable and therefore suited for the highest power levels.
The working principle of Gaussian mirrors is based on a Fabry Pérot interferometer with a fixed mirror spacing – a so-called etalon. In this way, the phase shift caused by the coating is minimized. Also, the wavefront distortion of coherent radiation is reduced.
The adjoining picture shows the cross-section of a coating that exhibits a gradual change in the reflection R(r) for monochromatic light depending on its position.
A so-called distance layer S with varying thickness d is surrounded by two identical mirror layers M. If d is an even multiple of l/4, the system is transparent for the wavelength and does not exhibit a reflection for l. If d is an odd multiple of l/4, the total reflection is determined by the reflection of the mirror layers M.
Special substrates are used for Gaussian mirrors. LASER COMPONENTS offers meniscus, plano convex, and other custom-made substrates.