Laser conditioning mechanism in DKDP crystals analyzed by fluorescence and stimulated Raman scattering technique

In order to analyze the mechanism of damage threshold enhancement after laser conditioning, the stimulated Raman scattering and fluorescent properties of un-conditioned and laser conditioned of DKDP crystals were compared in detail. It revealed that the intensity of Raman scattering peak 921cm-1 were slightly lowered, and the intensity of fluorescence was much decreased, especially the fluorescence below 400nm, after nanosecond laser conditioning. Moreover, the intensity of fluorescence could be further decreased after sub-nanosecond laser conditioning. The slightly variation of Raman scattering proved the modification of the PO4 vibrational modes. The sharply decrease of fluorescence intensity below 400 nm reflected the density reduction of electron defects in these crystals. On the basis of the above analysis, laser conditioning mechanism in DKDP crystals was discussed.

[1]  Bertrand Bertussi,et al.  Detection and characterization of absorption heterogeneities in KH2PO4 crystals , 2006 .

[2]  S G Demos,et al.  Wavelength dependence of laser-induced damage: determining the damage initiation mechanisms. , 2003, Physical review letters.

[3]  Stavros G. Demos,et al.  Production and thermal decay of radiation-induced point defects in KD2PO4 crystals , 2003 .

[4]  S G Demos,et al.  Microscopic fluorescence imaging of bulk defect clusters in KH(2)PO(4) crystals. , 1999, Optics letters.

[5]  Guillaume Duchateau,et al.  Electron-hole dynamics in normal and deuterated KH2PO4illuminated by intense femtosecond laser pulses , 2011 .

[6]  Stavros G. Demos,et al.  Transient material properties during defect-assisted laser breakdown in deuterated potassium dihydrogen phosphate crystals , 2014 .

[7]  Michael D. Feit,et al.  Implications of nanoabsorber initiators for damage probability curves, pulselength scaling, and laser conditioning , 2003, SPIE Laser Damage.

[8]  Jianda Shao,et al.  Mitigation of scattering defect and absorption of DKDP crystals by laser conditioning. , 2015, Optics express.

[9]  Guillaume Duchateau,et al.  Coupling statistics and heat transfer to study laser-induced crystal damage by nanosecond pulses. , 2007, Optics express.

[10]  Stavros G. Demos,et al.  Investigation of optically active defect clusters in KH2PO4 under laser photoexcitation , 1999 .

[11]  Stavros G Demos,et al.  Investigation of the electronic and physical properties of defect structures responsible for laser-induced damage in DKDP crystals. , 2010, Optics express.

[12]  Guohang Hu,et al.  Transmittance increase after laser conditioning reveals absorption properties variation in DKDP crystals. , 2012, Optics express.

[13]  Isao Kanesaka,et al.  NORMAL COORDINATE ANALYSIS AND STRUCTURE OF AMMONIUM DIHYDROGENPHOSPHATE , 1998 .

[14]  S G Demos,et al.  Electron- or hole-assisted reactions of H defects in hydrogen-bonded KDP. , 2003, Physical review letters.

[15]  A. K. Burnham,et al.  Developing KH2PO4 and KD2PO4 crystals for the world's most power laser , 2002 .

[16]  Stavros G. Demos,et al.  Differentiation of defect populations responsible for bulk laser-induced damage in potassium dihydrogen phosphate crystals , 2006 .

[17]  S G Demos,et al.  Investigation of laser annealing parameters for optimal laser-damage performance in deuterated potassium dihydrogen phosphate. , 2005, Optics letters.

[18]  S G Demos,et al.  Localized dynamics during laser-induced damage in optical materials. , 2004, Physical review letters.

[19]  Michael D. Feit,et al.  Results of sub-nanosecond laser-conditioning of KD2PO4 crystals , 2006, SPIE Laser Damage.