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Folienvorlagen für Seminarvortrag

Folienvorlagen für Seminarvortrag. Novel laser concepts. Slab laser. y. Disc laser. Slab. z. diode laser. focusing optic. focusing optic. disc. HR-mirror. diode laser. cooling. laser beam. Fiber laser. focusing optic. HR-mirror. out coupling mirror. HR-Spiegel. fiber.

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Folienvorlagen für Seminarvortrag

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  1. Folienvorlagen für Seminarvortrag

  2. Novel laser concepts Slab laser y Disc laser Slab z diode laser focusing optic focusing optic disc HR-mirror diode laser cooling laser beam Fiber laser focusing optic HR-mirror out coupling mirror HR-Spiegel fiber diode laser

  3. ri Double-clad fiber laser pump light inner cladding active core refractive index profile laser radiation n outer cladding meridional rays helical rays

  4. Improving pump absorption by pump core design

  5. Improving the pump-absorption by mode mixing kidney shaping

  6. M2~ 1 600 W Double clad fiber laser (today) most recent result … cw fiber laser: P= 1.3 kW M2< 3 @ MFD 25 µm (accepted @ CLEO postdeadline)

  7. Properties of fiber lasers • immunity against thermal problems • high gain • - low threshold • - high efficiency • - low intrinsic loss • - large interaction length • - exploitation of weak transitions • - large bandwidth • - tuneability • - short pulse generation + amplification • - STRONG NONLINEARITY

  8. Low-NA large-mode-area fiber design double-clad single-mode fiber active core n pump core core  <10 µm core NA = 0.1 – 0.2 absorption length > 20 m coating double-clad large-mode-area fiber active core n pump core core  = 30 .. 40 µm core NA = 0.06 .. 0.08 absorption length < 10 m coating increased mode-field diameter reduced fiber length reduced nonlinearity

  9. CPA-fiber amplifier – high average power system diode laser single-mode preamplifier fs-oscillator fiber stretcher 300 m, MFD = 6.6 µm Isolator Dl = 22 nm, Dt = 250 ps @ 15 mW Dl = 20 nm, Dt = 225 ps @ 2 W 1060 nm,150 mW, 150 fs, 75 MHz Isolator Transmission grating compressor diode laser Yb-doped power amplifier Output

  10. CPA-fiber amplifier – power amplifier Yb-doped large-mode-area fiber length: 13.5 m core:  = 28.5 µm, NA = 0.06, MFD = 23 µm inner clad.:  = 400 µm, NA = 0.38, D doping: 700 ppm (mol) Yb2O3 diode laser 976 nm Yb-doped power amplifier output characteristics beam quality: diffraction-limited (M2 = 1.1) degree of polarization: ~ 50% (3 to 1)

  11. CPA-fiber amplifier – power amplifier diode laser 976 nm Yb-doped large-mode-area fiber core:  = 28.5 µm, NA = 0.06 doping: 700 ppm (mol) Yb2O3 inner clad.:  = 400 µm, NA = 0.38, D length: 13.5 m Yb-doped power amplifier pulse duration at 140 W emitted spectrum at 140 W

  12. Air-clad large-mode-area microstructure fibers high numerical aperture inner cladding radiation not in contact with coating materials

  13. grating compressor to application Yb-doped power amplifier diode laser diode laser Yb:KGW oscillator diode laser AOM I AOM II preamplifier FR PBS preamplifier grating stretcher High energy fiber CPA system Inner cladding:  = 150 µm NA > 0.55 Core:  = 28 µm, NA = 0.05, MFD ~25 µm Pump light absorption: 9.6 dB/m @ 976 nm 250 fs 1 W 1 W ~10 kHz to ~MHz 750 ps

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