Device for generating a jet of liquid propagating along a jet axis, said jet of liquid guiding a laser beam, said device comprising: a) a distribution chamber with at least one inlet and at least one outlet for the liquid, said distribution chamber being of an annular shape encircling said jet axis, said distribution chamber having a first effective liquid flow cross-section area S1; b) an acceleration chamber having at least one inlet (12; 12.1 - 12.7) and one outlet for the liquid and a window transparent to said laser beam to introduce said laser beam into said acceleration chamber through said window, wherein said window is arranged in line with the jet axis to enable the introduction of the laser beam coaxial to said jet axis, said acceleration chamber having an entrance cross-section S3 defined by a surface area of a cylinder barrel of a geometric cylinder arranged coaxially to the jet axis, said cylinder barrel having a radius (r) corresponding to the smallest distance between the jet axis and said at least one inlet (12; 12.1 - 12.7) of the acceleration chamber, said area of the cylinder barrel being located within said acceleration chamber; c) a nozzle with a nozzle hole generating said jet of liquid, said nozzle being arranged in said outlet of the acceleration chamber and said nozzle hole defining a direction of the jet axis; d) a connection passage (6; 6.1 - 6.7) extending from the at least one outlet of the distribution chamber to the at least one inlet of the acceleration chamber (12.1 - 12.7), said connection passage (6; 6.1 - 6.7) having a second effective liquid flow cross-section area S2; e) the second effective liquid flow cross-section area S2 is smaller than the first effective liquid flow cross-section area S1, preferably by an order of magnitude: S 2 / S 1 < < 1 and f) the second effective liquid flow cross-section area S2 is smaller than the entrance cross-section S3: S 2 / S 3 < 1 characterized in that said device comprises a wall element having a central opening and a liquid supply connection with which the device may be connected to a liquid supply unit, wherein the liquid supply connection is in open communication with the distribution chamber into which it abuts by means of an inlet, wherein a nozzle holder comprising the nozzle and a window element comprising the window are arranged one above the other within said central opening, said nozzle holder and said window element being spaced from each other along said jet axis, said spacing defining said acceleration chamber, wherein said connection passage (6; 6.1 - 6.7) and said distribution chamber are formed within said nozzle holder. a) a distribution chamber with at least one inlet and at least one outlet for the liquid, said distribution chamber being of an annular shape encircling said jet axis, said distribution chamber having a first effective liquid flow cross-section area S1; b) an acceleration chamber having at least one inlet (12; 12.1 - 12.7) and one outlet for the liquid and a window transparent to said laser beam to introduce said laser beam into said acceleration chamber through said window, wherein said window is arranged in line with the jet axis to enable the introduction of the laser beam coaxial to said jet axis, said acceleration chamber having an entrance cross-section S3 defined by a surface area of a cylinder barrel of a geometric cylinder arranged coaxially to the jet axis, said cylinder barrel having a radius (r) corresponding to the smallest distance between the jet axis and said at least one inlet (12; 12.1 - 12.7) of the acceleration chamber, said area of the cylinder barrel being located within said acceleration chamber; c) a nozzle with a nozzle hole generating said jet of liquid, said nozzle being arranged in said outlet of the acceleration chamber and said nozzle hole defining a direction of the jet axis; d) a connection passage (6; 6.1 - 6.7) extending from the at least one outlet of the distribution chamber to the at least one inlet of the acceleration chamber (12.1 - 12.7), said connection passage (6; 6.1 - 6.7) having a second effective liquid flow cross-section area S2; e) the second effective liquid flow cross-section area S2 is smaller than the first effective liquid flow cross-section area S1, preferably by an order of magnitude: S 2 / S 1 < < 1 and f) the second effective liquid flow cross-section area S2 is smaller than the entrance cross-section S3: S 2 / S 3 < 1 characterized in that said device comprises a wall element having a central opening and a liquid supply connection with which the device may be connected to a liquid supply unit, wherein the liquid supply connection is in open communication with the distribution chamber into which it abuts by means of an inlet, wherein a nozzle holder comprising the nozzle and a window element comprising the window are arranged one above the other within said central opening, said nozzle holder and said window element being spaced from each other along said jet axis, said spacing defining said acceleration chamber, wherein said connection passage (6; 6.1 - 6.7) and said distribution chamber are formed within said nozzle holder.