Device and method for online measuring spectrum for laser device

A device for measuring a spectrum for a laser device, comprising:

• a first optical path assembly configured to homogenize a laser beam emitted by the laser device, and
• a second optical path assembly constituting a measurement optical path with the first optical path assembly, and configured to perform a dispersion imaging on the laser beam homogenized by the first optical path assembly,
• wherein the second optical path assembly comprises:
• an FP (Fabry-Perot) etalon, the homogenized laser beam passing through the FP etalon to generate an interference fringe;
• and
• a grating, configured to disperse the laser beam passing through the FP etalon, wherein the grating and the FP etalon are connected in series, and wherein the grating is arranged after the FP etalon, or is arranged before the FP etalon in the measurement optical path;
• wherein the second optical path assembly comprises:
• a diffusing sheet, a field diaphragm and a collimating lens arranged in sequence along the measurement optical path, wherein,
• the diffusing sheet is configured to diffuse the laser beam homogenized by the first optical path assembly;
• the field diaphragm is configured to control an imaging range of the laser beam diffused by the diffusing sheet in a dispersion imaging process, wherein the field diaphragm and the collimating lens are connected in sequence along the measurement optical path;
• and
• the collimating lens is arranged before the FP etalon in the measurement optical path, and is configured to ensure a collimation characteristic of the laser beam incident on the FP etalon,
• wherein the first optical path assembly comprises:
• a first beam splitter, a second beam splitter and a light homogenizing assembly arranged in sequence along the measurement optical path,
• wherein the light homogenizing assembly comprises:
• an optical light homogenizing element, a first convergent lens and a first reflecting mirror arranged in sequence along the measurement optical path, the optical light homogenizing element, the first convergent lens and the first reflecting mirror are connected in series, the optical light homogenizing element is arranged before the first convergent lens, and the first convergent lens is arranged before the first reflecting mirror;
• wherein,
• the light homogenizing element is configured to homogenize the laser beam, so as to eliminate an influence of the laser beam on a measurement of a spectrum for a laser device, and the light homogenizing element is a microlens array or an integrator rod;
• the first convergent lens is configured to converge the laser beam homogenized by the light homogenizing element to the first reflecting mirror;
• and
• the first reflecting mirror is configured to reflect the laser beam converged by the first convergent lens to a light facing surface of the diffusing sheet, and a light facing surface of the first reflecting mirror is coated with a high reflection film.