Microlaser cavity with mode selection, and manufacturing methods

摘要

The cavity includes entrance (34) and exit (36) mirrors and an active laser cavity (32), the diameter of one of the mirrors (34,36) being a disc of diameter equal to or less than the diameter of the fundamental mode. An intra-cavity diaphragm may also be provided which provides an annular or circular opening. The microlaser may have a stabilised plano-concave cavity in which the plane mirror has a diameter less than or equal to d where d4 = 16( lambda 2)R-L)/n2 2) and the concave mirror has a diameter less than or equal to D where D 4 = 16( lambda 2R2/(R-L)n2 2). In these expressions, lambda being wavelength of the fundamental mode of the laser, n the refractive index of the laser material, L the length of the cavity, and R is the radius of curvature of the mirror. The diaphragm permits oscillation of several modes while also inhibiting other modes.