Gaussian beam interaction with an air-gap Fizeau interferential wedge.

We describe a plane-wave-expansion approach for calculation of the fringe pattern in transmission and reflection for a Gaussian monochromatic beam. Both positive and negative incidence, at which the incident light beam undergoes multiple reflections within the wedge in direction of increasing or decreasing wedge thickness respectively, are analyzed. It is shown that the two opposite incidences of the light beam are described by the same mathematical expressions; i.

Two-wavelength, passive self-injection-controlled operation of diode-pumped cw Yb-doped crystal lasers.

We demonstrate and investigate a peculiar mode of cw Yb3+-doped crystal laser operation when two emissions, at two independently tunable wavelengths, are simultaneously produced. Both emissions are generated from a single pumped volume and take place in either a single beam or spatially separated beams. The laser employs original two-channel cavities that use a passive self-injection-locking (PSIL) control to reduce intracavity loss.