The present invention relates to a first container with an internal space for accommodating a vertical external cavity surface emitting laser device. Said first container hermetically seals said internal space from an external space, wherein said first container has at least one wall with at least one first through-opening. Said at least one first through-opening is adapted for passage of an optical pump beam from the external space into the internal space, and/or for passage of a laser emission beam from the internal space into the external space. Moreover, said at least one first through-opening is hermetically sealed by a sealing mirror, wherein said sealing mirror is adapted to form an external cavity of the vertical external cavity surface emitting laser device with a second mirror in the internal space. Furthermore, the present invention relates to laser device with such a first container and to an assembly method of the laser device.