Compact and highly efficient laser pump cavity

DETAILED DESCRIPTION To resolve these issues, an aspect of the present invention uses a new side-pumped scheme with a novel pump cavity configuration that improves laser performance.
According to one aspect of the invention, an elongated pumping structure oriented along a main axis includes an elongated pumping chamber and a plurality of elongated light concentration channels for coupling pumping radiation into the pumping chamber.
The elongated light concentration channels are tapered with a wide entry aperture and a narrow exit aperture so that light is likely to be injected into and trapped inside the elongated pumping chamber.
According to another aspect of the invention, the light concentration channels are compound parabolic concentrators (CPC) that effectively concentrate the light entering the large entry aperture to be transmitted through the small exit aperture.
According to another aspect of the invention, the sides of the light concentration channels are reflectively coated to specularly reflect light from the sides.
According to another aspect of the invention, the walls of the pumping chamber are coated to diffusely or specularly reflect light from the walls of the pumping chamber.
According to another aspect of the invention, the pumping chamber is segmented and specially shaped so that glancing rays are more efficiently and/or more homogeneously reflected into the laser medium.
According to another aspect of the invention, the coupling structure comprises segments which are assembled to form the coupling structure.
Each segment includes side surfaces which form the light concentration channels and curved inner surfaces which form the pumping chamber when the segments are assembled.
According to another aspect of the invention, a CPC is designed with a higher refractive index material (such as glass) for an improved light concentration.
According to another aspect of the invention, troughs with flat reflecting surfaces can also be applied to channel the pump light into the pump chamber