The invention discloses a defect detecting method and a defect detecting device for an iron-doped laser crystal. The device comprises a laser, a gauge diaphragm, a coated beam combiner, a coated beamsplitter, a laser sampling mirror, a laser power meter, a clamping component, a data acquisition card and a computer. The method comprises the following steps: combining detection laser of which two wavelengths strongly absorb and do not absorb iron ions; enabling the combined laser to enter a to-be-detected laser crystal; respectively detecting reflecting and transmitting power of the laser withthe two wavelengths on the surface of the to-be-detected laser crystal by adopting a laser power meter before the laser enters the to-be-detected laser crystal. The defect types and characteristics ofthe to-be-detected laser crystal can be obtained by computational analysis of tested data. Specifically, a power value obtained by no absorption of laser wavelength characterizes defect information such as bumbles, pocks and cracks; a transmitting power value obtained by laser wavelength strong absorption characterizes the defect information of non-uniform lateral doping of the laser crystal.

Defect detecting method and defect detecting device for iron-doped laser crystal

Thermal problem becomes more prominent in the highly-pumped laser gain mediums, for which, the forced convective heat transfer with the advantages of reliability and durability is widely used. However, a flow direction induced temperature gradient always appears within the laser operating substance during the convective heat transfer. Subsequently, it is significantly responsible for the detrimental thermal stress which mainly cause the wave front distortion. Herein, considering the idea of temperature matching between flow field and the operating substance, a cooling configuration for double face pumped slab crystal based on longitudinal forced convective heat transfer was presented, which showed a more efficient cooling and achieved a most homogeneous temperature distribution within the crystal. The influences of flow rate, state of flow field and surface roughness were systematically studied that a fully developed flow state, higher flow rate and rougher surface lead to an improvement in cooling capability. In the simulation with 30 L/min flow rate, the calculated convective heat transfer coefficient was as high as 104 W·m−2·K−1, and even higher when a more coarse surface was implemented. Furthermore, a module based on the configuration was fabricated and the experimental results agree well with the simulation, which shows a good temperature distribution and very weak thermal lensing is achieved.

Longitudinal forced convection heat transfer for high power slab laser media

Experimental study of variable thermal lens in a two-stage chirped-pulse high-power Ti:sapphire amplifier at 1kHz

Passively Q-switched laser based on Nd:YAG/YAG Polygonal Active Mirror with timing jitter improvement

The embodiment of the invention discloses a semiconductor laser testing system and method, used for a ring semiconductor laser. The semiconductor laser testing system comprises a ring semiconductor laser light source having at least two sets of light emitting units, a first light guide part, a rotary mechanism and a testing component. On the basis of the semiconductor laser testing system and method provided in the invention, in the normal working state of the ring semiconductor laser light source, laser emitted by various light emitting units can be tested one by one; furthermore, laser, which does not need to be tested, also can be exported; and thus, the testing precision and accuracy can be improved.

Semiconductor laser testing system and method

The invention relates to a measurement method and device for particle doping concentration uniformity of a laser crystal An LD optical fiber coupling module with central wavelength corresponding to a strong absorption peak of the laser crystal is used for outputting any axial cross section part of a pumped laser crystal, transmitted power is received by a power meter on the transmission surface of the corresponding laser crystal, the laser crystal is placed on an electric two-dimensional translation stage for scanning the received transmitted power point by point, data of point-by-point scanning is fitted into a power space distribution three-dimensional graph after absorption in a corresponding cross section direction of the laser crystal, and power points which transmit the crystal and are tested by the power meter are subjected to data processing, and relative value of the crystal particle doping concentration uniformity and space distribution results are obtained The device is simple in structure, lower in cost, simple to operate, stable and reliable, and can solve the measurement problem of the particle doping concentration uniformity of laser crystals having different shapes and made of different materials by replacing pumping sources with different output parameters

Measurement method and device for particle doping concentration uniformity of laser crystal

The invention relates to a single bar power and stability measuring device in laser diode lamination array and the method, comprising a laser diode lamination array, a light guiding pipe, a horizontally moving station, a light separation waveguide reflector, an integrating sphere, a detection window, a power meter, and a parasitic light collector. The lasers emitted by the different single bars in the laser diode lamination array are dispersed and laminated quickly in the rapid shaft direction. The light guiding pipe is arranged right in front of the to-be-detected single bars. The lasers emitted from the to-be-detected single bars can be completely coupled into the light guiding pipe, and the lasers emitted from the bars of other diodes enter the light separation waveguide reflector, and at the inclined edges of the light separation waveguide reflector, reflection occurs, and the light enters the parasitic light collector, rather than the light guiding pipe. Through the outlet of the light guiding pipe, the light enters the integrating sphere, and after the light is uniformed in the integrating sphere, the power meter tests the power of the lasers of the single bar. Through the horizontally moving platform to move the laser diode lamination array, the single bars in the lamination array are aligned with the light guiding pipe so that the power and the power stability performance of the single bars in the lamination array can be tested.

Single bar power and stability measuring device in laser diode lamination array and the method

A compact polygonal active-mirror (PAM) laser with composite Nd: YAG/YAG multithin-disk gain medium has been demonstrated with total internal reflection scheme. Five Nd:YAG thin disks with a neodymium concentration of 0.7 at.% and thickness of ∼0.2 mm were bonded to five different surfaces of a hexagonal YAG substrate. With no heat sink, output power of 1.03 W at 1064 nm and beam quality of M2 = 1.21 was obtained from a short-cavity oscillator based on the PAM architecture, under an absorption pump power of 2.30 W, with a slope efficiency and optical to optical efficiency of 55.8% and 44.8%, respectively.

Compact Polygonal Active-Mirror Laser With Composite Nd:YAG/YAG Gain Medium

The transient thermal distribution and thermally induced beam quality (M
 2) degradation in low repetition (10 Hz) and hundred-mJ-level end-pumped Yb:YAG slab amplifiers with different thicknesses are discussed. Using Fast Fourier Transformation, the output beam quality is evaluated for different pump conditions, including variable pump power, single- or double-end pumping, and different pump beam widths. Simulation results show that for a slab amplifier operating at low repetition rates and high pump energy levels, adequate thermal property and output beam quality can be achieved by simply increasing the slab thickness.

Lifen Liao

Papers

Measurement method and device for particle doping concentration uniformity of laser crystal

Single bar power and stability measuring device in laser diode lamination array and the method

Compact Polygonal Active-Mirror Laser With Composite Nd:YAG/YAG Gain Medium

Simulation of the transient thermally induced beam quality degradation in end-pumped slab Yb:YAG amplifiers of hundred-mJ-level

Passively Q-switched laser based on Nd:YAG/YAG Polygonal Active Mirror with timing jitter improvement