Blue laser operating at the H-beta Fraunhofer line

A blue laser system comprising a laser source and a frequency quadrupling system (FQS);

• a) Said laser source being a laser oscillator including a pump module, a dichroic mirror, a laser gain material, a polarizer, a q-switch, a one-quarter wave plate, and a Volume Bragg Grating (VBG), and means for temperature control of said VBG;
• b) said laser source being arranged such that said laser oscillator delivers an output laser beam;
• c) said laser gain element selected from the family consisting of Tm:Lu2O3, Tm:Y2O3, and Tm:Sc2O3;
• d) said VBG being arranged to restrict said output laser beam of said laser oscillator to a wavelength band of 1944.537±0.100 nm measured in air at standard conditions;
• and
• e) said FQS comprising a first harmonic converter stage and a second harmonic converter stage wherein laser light resulting from said lasing at said 1944.537±0.100 nm arranged to be converted in said FQS to a wavelength of about 486.13 nm measured in air at sea level and corresponding to the vicinity of the H-beta Fraunhofer line.

A method of generating coherent laser radiation of a wavelength centered at 486.13 nm corresponding to the Fraunhofer H-beta line comprising the steps of

• a) Operating a laser source including a pump module, a Tm:Lu2O3 laser gain material;
• (LGM), a q-switch, a Volume Bragg Grating (VBG);
• b) Temperature tuning the center wavelength of said VBG to four times the wavelength of said Fraunhofer H-beta line;
• c) Closing the g-switch shut;
• d) Pumping said LGM by said pump module;
• e) Storing laser energy in said LGM;
• f) Opening said q-switch;
• g) Extracting laser power at 1944 nm wavelength from said LGM through said VBG;
• h) Converting a portion of said laser power at 1944 nm wavelength to a first harmonic at 972 nm wavelength in a first harmonic converter stage;
• i) Converting said first harmonic at 972 nm wavelength to a second harmonic at 486 nm wavelength in a second harmonic converter stage;
• and
• j) Closing said q-switch shut.