Lecture Course: Laserphysics II - Laser Spectroscopy and Technical Applications

 

by

 

Dr. A. Volkmer

 

LASER SPECTROSCOPIES

 

I Introduction

-          Specific properties of laser radiation

 

-          Methods in lasers spectroscopy (an overview)

 

 

II Linear Spectroscopy

-          Methods with high detection sensitivity

-          Direct absorption measurements (attenuated total internal reflection spectroscopy (ATIR), Frequency modulation (FM) spectroscopy, intracavity absorption spectroscopy, cavity-ring-down spectroscopy)

-          Direct measurements of photons absorbed (Laser excitation spectroscopy, Laser-induced fluorescence spectroscopy)

-          Example: Single-molecule spectroscopy

-          Methods with high spectral resolution

-          Doppler-broadening in atom and molecular gases

-          Atom/molecular beam spectroscopy (geometric cooling)

-          Laser cooling (optical cooling) (example: Generation of BEC)

-          Double-resonance spectroscopy (optical pumping, optically-detected magnetic resonance (ODMR), optical-optical double resonance (OODR; V- and lambda-type))

 

III Nonlinear Spectroscopy

-          Nonlinear absorption spectroscopy (saturable absorption and saturation spectroscopy of a homogeneously broadened absorption line and of an inhomogeneously broadened absorption line (hole-burning))

-          Multi-photon processes (two-photon transition probability and selection rules, general description of multi-photon transitions, time-dependent higher-order perturbation theory, photo-selection of excited state population, spectroscopic applications)

 

IV Ultrafast Spectroscopy

-          Generation and description of ultrashort laser pulses (Q-switching and mode-locking, pulse compression techniques)

-          Characterization ultrashort laser pulses (autocorrelation techniques, frequency-resolved optical gating (FROG))

-          Spectroscopy with high temporal resolution (direct pump-probe spectroscopy (time-resolved OODR), indirect pump-probe spectroscopy (optical gating), fluorescence up-conversion, optical Kerr gate, the Austin switch)

 

V Coherence Spectroscopy

-          Quantum-beat spectroscopy (level-crossing spectroscopy (Hanle effect)

-          Perturbation of a two-level system by a coherent field (density matrix formalism, optical nutation (Rabi oscillations), optical Bloch equations, free induction decay (FID))

-          Super-radiance (coherent enhancement effect)

-          Photon echo spectroscopy

-          Self-induced transparency (SIT)

 

TECHNICAL APPLICATIONS OF LASERS

 

VI Lasers in measurement methods and instrumentation

-          Geodesy (laser pointing and marking)

-          Long-distance determination (laser pulse echo technique, cw-laser modulation technique, light detection and ranging (LIDAR))

-          Interferometric determination of small distances

-          Heterodyned interferometry

-          Holographic interferometry (3D)

-          Linear velocity determination (Laser anemometry)

-          Angular velocity determination (the Laser Gyroscope)

 

VII Lasers in information technology

-          Fiber optical communication (fiber and optical wave-guides, Eigen modes and mode dispersion, fiber and optical wave-guide coupling, material attenuation, optical solitons)

-          Optical modulators/de-modulators

-          Optical switches (electro-optical modulator (Pockels cell), acusto-optical modulator (Bragg cell))

-          Wavelength division (de)multiplexing

-          Power amplifier (opto-electronic amplification, Erbium-doped fiber amplification (EDFA))

-          Coherent optical communication

-          Optical data storage (optical disk (CD-RW), holographic storage in 3D)

-          Spectral hole-burning

-          Laser printing

-          Image displays by lasers

 

VIII Lasers in high-energy physics

-          Generation of high laser pulse intensities (chirped-pulsed amplification, example: NIF and LMJ facilities)

-          Physics with high-intense laser pulse (plasma formation, relativistic optics, photo- and thermo nuclear reactions)

 

IX Lasers in Chemistry

-          Isotope seperation with lasers (selective multi-step ionization, dissociation or chemical reaction)

 

X Lasers in material processing

-          Laser chemical processing (deposition, ablation, etching, alloying, metallization, and polymerization)

-          Laser physical processing (regimes of laser-material interaction, laser processing techniques: laser cutting, drilling, welding, and ablation)

 

XI Lasers in medicine

-          Light absorption and penetration depth in tissue

-          Laser surgery (Examples: Ophthalmology, coagulation of blood vessels)

-          Photodynamic therapy of cancer

-          Laser-based diagnosis techniques (analytical laser spectroscopy, 3D-imaging of cell morphology by laser scanning microscopy, confocal fluorescence and nonlinear microscopy, 3D-imaging of tissue by optical coherence tomography (OCT), blood flow measurements by Doppler anemometry)