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Research On 1.53μm Eye-safe Laser Optical Parametric Oscillator

Posted on:2011-03-18Degree:MasterType:Thesis
Country:ChinaCandidate:H B ChenFull Text:PDF
GTID:2198330332980839Subject:Optics
Abstract/Summary:PDF Full Text Request
Lasers operating around 1.5μm locate within the absorption band of water molecules and the characteristics of eye safety. For this reason,1.5μm eye-safety lasers have the application foreground in the fields involving bio-medicine, optical communication, precision measuring and laser-guided weapons, etc. Optical parameter oscillator (OPO) has advantage of tunability, the tunable range can be from ultraviolet to far infrared, which makes up the disadvantage of the common lasers only emitting a single wavelength. Optical parametric oscillator is an efficient means for producing 1.5μm eye-safety laser pumped by 1.064μm laser. In this paper, the theoretical and experimental studies for 1.53μm eye-safe laser were made based on KTA nonlinear crystal and OPO technology. A highly efficient 1.53μm laser output was realized.In this paper, the development and the status of eye-safe lasers were introduced and the technical approaches for achieving 1.5μm wave band laser were compared as well. The principle of OPO for achieving laser frequency conversion was expatiated by the aid of the theory of nonlinear optics. The physical properties of laser crystals Nd:YAG, Nd:YVO4 and the nonlinear crystal KTA were systematically summarized. The phase match situation of KTA crystal has been emphatically analyzed. For the OPO experiments, the incavity KTA-OPO with non-critical phase matching cut pumped by xenon lamp and laser diode were separately studies.In the xenon lamp-pumped KTA-OPO experiment, we have achieved 90mJ energy for signal light under the lamp-pumped energy of 28.2J. The fundamental frequency light energy inside cavity was about 388mJ, which could be calculated by fundamental frequency light energy of 12mJ measured outside cavity. The optical to optical conversion efficiency was nearly 23.2%.In LD end-pumped KTA-OPO experiment, we have achieved 2.6 W average power for signal light under the LD pumping power of 13.7W and the pulse repetition rates of 60 kHz, corresponding to an optical-to-optical conversion efficiency of 19%. As we know, it is the highest conversion efficiency for the reported intra-cavity OPO based on KTA using LD end-pumping configurations so far.
Keywords/Search Tags:OPO, KTA crystal, Nd:YVO4 crystal, Eye-safe Laser
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