Font Size: a A A

LD Pump Nd:GdVO4 1.34μm And Frequency-doubled Laser

Posted on:2006-03-06Degree:MasterType:Thesis
Country:ChinaCandidate:Q Q PengFull Text:PDF
GTID:2168360155459845Subject:Optics
Abstract/Summary:PDF Full Text Request
Diode pumped solid-state laser (DPSL) is applied extensively in fields of military, medicine, information technology, industry and science research for its possessing advantages of high total efficiency, long longevity, good beam quality, all solid state, concise structure, small volume, light mass, and so on. In high power operation, laser crystals will generally absorb the pumping heat and then produce the thermal effect, which influences the laser performances. And the heat induced fracture also limits the maximum pumping power the crystals can endure and the fields it can be used. Recently, Nd:GdVO4 laser crystal has been widely used because it has the same good laser performance as Nd:YVO4 and high thermal conductivity as Nd:YAG. The 1.34 μm wave is safe for human eye and coincides with the silicon optical fiber transform, so it has wide application potential in medicine, communication, optical remote sense. The 671 nm red output produced by doubling frequency of 1.34 μm with KTP crystal intra-cavity can replace the Ar ion lasers and the Kr ion lasers which are expensive, with low efficiency and complicated structures. The Q-switched technology can produce pulses with super high peak power and very narrow width, which makes pulsing lasers available extensively in medical treatment, distance measuring, manufacturing, optical polymerization , underwater communication and atmosphere pollution survey.This paper mainly studies the LD end-pumped Nd:GdVO4 laser, measures the continuous wave and the Q-switched output characterization of 1.34 μm wave, and the transformed the frequency to get the red laser output. The contents are as follows:1. The diode pumped solid state lasers and diode pumped solid state laser materials briefly are described. The advantage of the solid state lasers and the main performance of LD pumped laser crystal are introduced, and the perspective and hit solid state lasers and the main content of the paper are generalized.2. The several aspects of the thermal effects of the laser crystal are discussed. Thethermal effect on parameter mode design was discussed from the point of thermal effect, the matrix transformation of Gauss beam and ABCD law. We studied the 1.34 μm laser output of the Nd:YVO4 and compared with the 1.06μm output. We used simple plane-concave cavity and varied the cavity length to study. When the cavity length is 3 cm, incident pump power is 7.56 W, maximum continuous output power of 1.34μm is 2.39 W, with slope efficiency of 36.5% and optical-optical transform efficiency of 31.7%.3. The effects of pumping and oscillating wave profile on the laser operation by surveying the differential equation of the gain material saturation cavity are studied. Take Nd:GdVO4 laser crystal for example, the output characterization numerically and then got theory model is calculated, providing condition for the cavity design and the neatly operation of experiment. In a plane-concave cavity configuration, with pump power of 7W, a 4mm long crystal with Nd3+ ion population intensity of 1.3at.% producemax output power of 1.65 W at 1.34μm, with optical-optical transform efficiency of 27.8% and slope efficiency of 31%; while a 9 mm long crystal , with 0.78at.%, produced the max of 1.58W, the corresponding optical-optical efficiency of 25.9%, and slope efficiency of 28%.4. the optimum coupling parameter's curve of max output energy , abstract efficiency, peak power and FWHM pulse width et al. are analyzed and the specific Q-switched optimum coupling output characterization of Nd:GdVO4 1.34μm laser are discussed. We used acoustic-optical Q-switch, and LD end pumped Nd:GdVO4 laser in plane-plane cavity, plane-concave and folded cavity to get 1.34μm laser pulse with high repeat frequency and short pulse width. In plane-concave cavity, we get max average output power of 253mW, with optical-optical transform efficiency of 3.2% and slope efficiency of 4.3% and the output power was 8W, the shortest pulse width, max single pulse energy and the highest peak power was 78ns, 20.1μJ and 265W respectively. In folded cavity configuration, the average output power in different repeat frequencies (5kHz,10kHz,15kHz,20kHz) are compared, and the shortest pulse width of 45 ns is gotten when the pump power is 6.8W and the repeat frequency is 5kHz.5. The LD end pump solid state laser intra-cavity doubling frequency according tothe frequency doubling theory are studied, and nonlinear crystal's critical and uncritical phase match, and the optical frequency doubling characterization of KTP crystal are discussed. The KTP frequency intra-cavity doubling laser with a simple plane-plane cavity is used for the first time, and single pass continuous red output of 50.7mW is gotten, with optical-optical transform efficiency of 1.5%. And 671nm red laser is also gotten using plane-concave and three mirror folded cavity configuration. In folded one, when pump power was 7W, single end continuous red output of 60 mW was achieved and the optical-optical transform efficiency is 1.7% correspondingly.
Keywords/Search Tags:Laser Diode, Nd:GdVO4, KTP, intra-cavity frequency-doubled, A-OQ-switched
PDF Full Text Request
Related items