Dissertation > Excellent graduate degree dissertation topics show

Study on Surface Domain Inversion and Ablation of Ferroelectric Crystal by Femtosecond Laser

Author: ZhuHaiSheng
Tutor: ChenXianFeng
School: Shanghai Jiaotong University
Course: Optics
Keywords: Femtosecond laser Domain inversion Ferroelectric crystal Lithium niobate Mg-doped Lithium niobate Ablation
CLC: TN249
Type: Master's thesis
Year: 2009
Downloads: 80
Quote: 1
Read: Download Dissertation

Abstract


With the development of femtosecond laser, the application of laser and the research area of interaction between laser and materials have been widened. In this dissertation, a novel method for domain inversion of ferroelectric crystal, domain inversion induced by femtosecond laser, has been proposed with simulation study and experimental investigation. Besides, the surface ablation of lithium niobate and Mg-doped lithium niobate by femtosecond laser has also been studied, which can help to get a deeper understanding of the anti-damage characteristic of ferroelectric crystal and also has important reference on the microfabrication in such materials by femtosecond laser.In our simulation model of domain inversion, which describes the process of electric field of laser acting on the crucial ions in domain inversion, that the domain inversion can actually be induced by laser in domain inversion window has been found, which alternates with un-inversion window as the energy of laser growing. Study of the parameters of the model shows that the decrease of damping constant, coupling spring constant, temperature, duration of the pulse and frequency of the laser field, will more or less reduce the inversion threshold, while a smaller laser waist radius will bring to a smaller domain inversion area. Carrier Envelope Phase (CEP) also plays an important part in the inversion process. When the value of CEP is about 0.5π, more laser energy will be devoted onto the domain inversion which can help to induce the possibility of domain inversion Simulation of the model for lithium niobate clarifies that the domain inversion by infrared femtosecond laser has a threshold in the range of 1~100μJ.Ring-like domain inversion window of lithium niobate induced by 800nm femtosecond laser, which has a polarization parallel to z axis of the specimen, has been observed. However the inversion becomes harder when the laser polarization turns an angle of 90 degree, which means the domain inversion is caused by electric field as is simulated in the model. Results show that the inversion threshold is between 1~4J/cm2 corresponding to laser energy of 30~60μJ, which is agreeable with our theoretical predictions. Besides, the experiment has been improved by using lens with focal length of 150mm and adjusting the position of focal point 10mm away from the specimen. Such a domain inversion induced totally by laser creates a path to achieve domain inversion structure in 3-dimension.Finally, the surface ablation of lithium niobate and Mg-doped lithium niobate under irradiation by single and multiple femtosecond laser pulses has been studied, and their ablation thresholds have been found out by using the logarithm relation of the ablation area and the laser energy fluence. Results show that when lithium niobate is Mg (5mol%) doped, its single pulse ablation thresholds increases 50% and its multi pulse ablation thresholds reduces more slowly as the pulses number increases. Another research for the comparison of Mg (5mol%): LiNbO3 and Mg (6mol%): LiNbO3 shows that the former one has a better anti-damaged characteristic.

Related Dissertations

  1. Study on Properties of Thermal Shock and Ablation Resistance for Gr/Al-Mg Composites,TB332
  2. Water-mdeiated Ablation of Hard Biotissue with Pulse Lases,R318.51
  3. Femtosecond laser and Si \u003csub\u003e 3 \u003c/ sub\u003e N \u003csub\u003e 4 \u003c/ sub\u003e crystal interaction theoretical study,O734
  4. The Study of Correlation between Left Atrium Scar Area with Radiofrequency Ablation Destination and Prognosis in Persistent Atrial Fibrillation Patient,R541.75
  5. The Impact of Age on the Electroanatomical Characteristics and Clinical Outcome after Catheter Ablation of Patients with Atrial Fibrillation,R541.75
  6. The Research on the Therapeutic Effect of Microwave Ablation (MA) Combined with Injection of 5-fluorourac in Mice Bearing CT26 Colon Carcinoma Xenogrsfts,R735.35
  7. Visual Quality Assessment between Different Ways Assisted Customized LASIK by OQAS,R779.63
  8. Study of Titanium-modified Phenolic Resins,TQ323.1
  9. All-optical Logic Gates Based on Electro-optic Effect in Periodically Poled Lithium Niobate,O439
  10. Clinical Research of Hot Lipiodol Ranscatheter Hepatic Arterial Chemoembolization Combined with Percutaneous Acetic Acid Interventional in Patients with Advanced Liver Cancer,R735.7
  11. Overweight Patients with Paroxysmal Atrial Fibrillation Might Benefit from Induction Strategies after Pulmonary Vein Isolation,R541.75
  12. Study of Field Emission Properties of Printed Carbon Nanotube Films,TB383.1
  13. Experimental Study on Ultrasonically Guided Microwave Ablation Therary for VX2 Breast Carcinoma in Rabbit,R735.7
  14. Research on Preparation of Reactive Metal Nanoparticles by Laser Ablation,TB383.1
  15. An Experimental Investigation on the Preparation of Ag Nanoparticles by Femtosecond Laser Ablation,TB383.1
  16. HVPE grown GaN thick film technology research,TN304
  17. Study on Thermal Transport of Argon Nanometer Thin Film with Molecular Dynamics Simulation,TB383.1
  18. The Features of Anatomic Landmarks in the Atrium Relevant to Interventional Electrophysiologic Techniques Demonstrated with 64-detector CT: A Preliminary Study,R541.7
  19. Load epirubicin chitosan microspheres and simply combined with microwave ablation in mice with subcutaneous tumor efficacy of liver transplantation,R735.7
  20. Research and Design of integrated optical waveguide electro-optical analog - to - digital converter,TN252
  21. 1560nm CW Frequency Doubling and Frequency Locking via Rubidium Absorption Spectroscopy,TN241

CLC: > Industrial Technology > Radio electronics, telecommunications technology > Photonics technology,laser technology > Laser technology, the maser > Laser applications
© 2012 www.DissertationTopic.Net  Mobile