Beijing Center for Crystal R&D, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Chuangtian Chen)

Transcription

1 Beijing Center for Crystal R&D, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences Chuangtian Chen) Recent Advances for UV and Deep-UV NLO Crystals and Applications Co-Workers: Watanabe s group, Institute for Solid State Physics, University of Tokyo Zu-Yan Xu s Group Institute of Physics, Chinese Academy of Sciences Ji-Yang Wang group, State Key Laboratory of Crystal Materials, Shandong University

2 Nonlinear Optics and NLO Crystals Ruby 694 nm laser focused on quartz to produce 347 nm UV laser, Very low efficiency. (Peter Franken et al. 1961) 2ω ω (2) χ ω

3 ω Birefringence Phse Matching (BPM) (2) χ 2ω ω I 2 ω = βi ω ΔkL sinc 2, 2 k = 2π n λ { Δω = ω Δ k = k 2 2ω 1 = 2 2k 1 = 0 0 n e (2ω) = n o (ω) PDMakeret al PRL P.D.Maker et al., PRL 1962

4 Laser promotes NLO crystal research NLO crystal stimulates laser application e a 0 N hν E r + - ω 2ω ω (2) χ ω To produce new wavelength

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6 Flux growth of KTP crystal

7 TSSG GROWTH KTP CRYSTAL

8 TSSG GROWTH KTP CRYSTAL

9 193 nm Laser Source Semiconductor industry lithography alignment inspection Spectroscopy Medical instruments Biotechnology Nikon Core Technology Center 2

10 Condition & Results Average power : 3mW at 10 khz Irradiated d area : 1mm x 1mm (PTK) Exposure time : 9 minutes Ablated depth : > 200 micron Nikon Optical microscope image SEM image Core Technology Center 21

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12 Important applications (1) Precision processing and micro-machining (266 nm) and in the future (193 nm and nm) (2) Photolithography: 193 nm and 157 nm (?) (3) Fabrication of photonic devices (193 nm and nm) (4) Medical application( fs,193 nm in particular) (5) Laser Photoemission i spectrometer t

13 Anion group theory The structure for high NLO effects: ects 1. Basic structure for NLO crystal Molecule and group; 2. For anion groups: (1) Polyhedrons, large distortion; (2) Lone electron pair; (3) Conjugated systems, planar. 3. Space effect: geological additive: NaSbF 5, KB 5 4. As much as possible in a unit volume.

14 Borate crystal chemistry 1) A boron atom can link either three oxygen atoms to form a triangular BO 3 group or four oxygen atoms to form a tetrahedral BO 4 group. BO 3 BO 4 2) Polyborate groups are formed from these triangles and tetrahedra by corner-sharing. In the groups containing three or more boron atoms, the basic structure is a six-memberedring with alternate boron and oxygen atoms. B 3 O 6 B 3 O 7 B 3 O 8 B 3 O 9

15 Crystals with B 3 O 6 group UV absorption edge: 189nm NLO coeffs: d 22 =4.1 d 36 (KDP) BBO crystal d 31 =0.07 d 22 Damage threshold: 10GW/cm 2 C.Chen et al.,sci. Sin. B28, 235(1985) BBO has been widely applied to harmonic generations in the visible and UV spectral region. Because of the limitation of the bandgap, It can not be used in DUV range.

16 Basic properties of LBO crystal UV absorption: 160nm NLO: d 31 = 2.5 d 36 (KDP) d 32 = 2.7 d 36 (KDP) Damage threshold: Birefringence : GW/cm 2 (0.1 ns, 1064 nm) Due to the very high damage threshold, relatively large NLO coefficients and wide transparent range, LBO is one of the mostly effective materials available at present for the UV and visible generation. The birefringence of LBO is too small to produce harmonic generation in the deep UV.

17 Bulk LBO

18 Crystal with B 3 O 7 group CBO (CsB 3 O 5 Crystal) YW Y.Wu et al., Appl. Phys. Lett. 62, 2614 (1993) UV absorption: 167nm NLO : d 14 = 2.7 d 36 (KDP) Damage threshould: 26 GW/cm 2 (1.0 ns, 1053 nm) The boron-oxygen networks in CBO are yg very similar to that in LBO

19 The structures of CBO and LBO. LBO: point group mm2 CBO : point group 222. Their effective NLO coefficient are different CBO+LBO => CLBO Interacting wavelengths Crystal d eff (d 36 (KDP)) SHG: CBO 1.2 LBO 2.4 THG: CBO 2.7 LBO 1.9 CBO is more favorable for THG than LBO.

20 Linear and nonlinear optical properties of KBBF and SBBO family Crystal Ponit group Transparent d ij Δn Range (nm) (pm/v) ( nm) Shortest SHG Wavelength (nm) KBBF D d 11 = SBBO D 3h d 22 =? TBO D 3h d 22 =? BABO D d 11 = KABO D d 11 = SBBO: Sr 2 Be 2 B 2 O 7 ; BABO: BaAl 2 B 2 O 7

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22 K B Be F O Space structure of KBBF

23 KBBF:KF:B 2 O 3 =1.5:5.0:0.8 Temperature o C -5 o C/d 20 days

24 KBBF Single Crystal

25 KBBF crystal morphology Atom distance: 0.48nm a=0.4427nm

26 Basic Data of KBBF (KBe 2 BO 3 F 2 ) Crystal Space group: R32 Unit cell: a =b = 4.427(4) 427(4) Å c = (9) Å z = 3 Density: 2.41 g/cm 3 Decomposition temperature: (820±3) C Melt point: 1030 C No other phase at from room temperature to 820 C Chem-Physical Properties: No hygroscopicity y layer habit Good mechanical property Hardness: BBO Growth method: top seed with flux Size of KBBF crystal: Year 2003: mm 3 Year 2004: mm 3

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29 Transmittance incident angle 0 random polarization Tran nsmittance (%) Wavelength nm Curve of KBBF transmittance

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31 d 11 = pm/v L=0.55 mm Maker fringes of KBBF crystal G.L.Wang et al. Chin.Phys.Lett. 20(2), (2003)

32 Optically contacted Prism Coupled KBBF Thickness is limited to 1.8 mm z-cut is impossible Apex angle 60.0 deg. +4 Thickness 1.2 mm z-axis CaF2 5 CaF2 Optical Contact KBBF

33 KBBF-Glass prism KBBF C.T.Chen et al. Chin.Phys.Lett. 18(8), 1081 (2001) Patent No. Z X(China) 10/125,024(USA) cm

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35 FoHG from KBBF crystal 358.7nm 179.4nm

36 Sixth Harmonic Generation of Nd:YVO4 Laser

37 SHG by KBBF (177.3nm) SH H-Power ( nm) [mw] f = 200 f = 300 f = Fundamental Power (355 nm) [W] SHG by KBBF from 355nm to 177.3nm 177.3nm output t power: 3.5mW T.Togashi Togashi et al. Opt.Lett. 28(4), (2003)

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39 Ps SHG: 177.3nm, 12.95mW 177n nm Power (mw) Power 12.95mW 10ps 80MHz 160um 355 nm pump P 4 W Duration 10 ps Frequency 80 MHz nm Power (W)

40 Ns SHG: 177.3nm, 34.7mW r (mw) mW 177.3nm powe nm pump P: 4.2W Duration 49ns Frequency 10kHz

41 ps 177.3nm output stability Long time work: More than 1000 h.

42 SHG Intensit ty [mw] SHG by KBBF (197nm) Fundamental (394 nm) [mw] SHG of KBBF (394 nm 197 nm, 1kHz, 17 ns)

43 ns Ti S Tunable DUV Laser system

44 Tunable Ti S FoHG ns 4HG pow wer (mw) KBBF-I 193nm 2.3mW KBBF-II Wavelength th( (nm) nm 8 khz

45 Light sources for Photoemission Spectroscopy Light source DUV DPL Synchrotron DUV light Energy resolution mev Photon flow Photon/s Photon flow density Photon/s.cm Wavelenrth (nm) Modes ns ps fs pulse ns ps pulse cw Deepth nm Body effect Surface effect ( Surface effect)

46 (a) Electron analyzer (b) Intensity (arb.units) data fit ΔE = 360 μev Gold hν = ev T = 2.9 K E F Binding energy (m ev) electron Sample E CaF 2 CaF 2 lens view port Fused silica view port Optically-contacted prism-coupled KBBF Quasi-CW Frequency-tripled Nd:YVO 4 laser 4 Fig. 1 Ultrahigh resolution photoelectron spectrometer Ultrahigh resolution photoelectron spectrometer (sub-mev)

47 Angle-resolved Photoemssion Spectroscopy Instrumentation Data processing Materials Scientific issues

48 Angle- Energy resolved Photoemssion Spectroscopy

49 ~30 mev EDC In ntensity (Ar rb. Unit) Bi2212 Nodal hv=6.994 T=18K 15 mev Energy (ev)

50 KBBF November 23, 2006 Bi2212 Tc=90K T=18K hv=6.994 ev (0,0) (p,p) (p,p) direction

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52 Fermi Surface from ARPES Fermi Surface of Sr 2 RuO 4 Band Structure Calculations Γ M Γ M M X M X Luttinger volume obeyed to within experimental error (4.02 electrons in 3 bands Excellent quantitative agreement with both band structure and de Haas-van Alphen K.M. Shen, A. Damascelli, et al. (PRB 01) A. Damascelli, D.H. Lu, K.M. Shen, et al. (PRL 00) I.I. Mazin & D.J. Singh (PRL 97)

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54 Photoemission spectroscopic evidence of gap anisotropy in Photoemission spectroscopic evidence of gap anisotropy in an f-electron superconductor, Phys.Rev. Lett. (2004)

55 Quartz Rotator LBO ω 1.7 W 780 nm 4.2 W ω+2ω B B O 25W W ω Quartz Rotator 3ω 1 W ω BBO ω 4ω Quartz Rotator 5ω 156 nm KBBF Chamber

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57 In the future: (1) 100 mw QCW 193 nm output power with 4 th HG of Ti:sapphire Laser (2) 100 mw QCW nm output power with 6 th HG of Nd:YAG Laser (3) Wide tunable coherent light output from 200 nm nm with 4 th HG of tunable Ti:sapphire Laser

58 Thank You!