Approximations of V(R) potential

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Table of contents

1 Introduction 
2 The He2* metastable molecule 
2.0.1 Binding between two He atoms
2.0.2 Formation rates for He2∗
2.1 Theoretical description of molecular dimer
2.1.1 Approximations of V(R) potential
2.1.2 Electronic molecular states
2.1.3 Symmetries of the rotational levels and transition selection rules
2.2 Intensities of the rotational lines of a3Σ+u (0)- e3Πg (0) transition and molecular densities
3 Blue laser setup 
3.1 Second Harmonic Generation in PP-KTP
3.1.1 Quasi-phase-matching
3.1.2 Conversion efficiency
3.1.3 Matching tolerances
3.2 465 nm laser setup – description
3.2.1 Laser setup components
3.2.1.1 Laser diodes
3.2.1.2 Nonlinear PP-KTP crystal
3.2.2 Setup for SFG – construction scheme
3.2.3 Laser output wavelength tuning
3.3 Laser performance – experimental results
3.3.1 Output power and efficiency
3.3.2 Tuning range and matching conditions
3.3.2.1 Laser wavelength calibration
3.3.2.2 Matching conditions
3.3.3 Matching tolerances in the experiment
3.4 Summary and conclusions
4 Absorption measurements on helium molecule – experimental results 
4.1 Experimental setup
4.1.1 Cell and rf discharge
4.1.2 Laser frequency scans. Acquisition scheme
4.1.3 Frequency scans recordings procedure
4.1.4 Measurements of the density decay times
4.2 Data processing and data reduction
4.2.1 Processing of the recorded data files in numerical lock-in software
4.2.2 Absorption line profile position determination
4.2.3 Absorbance and demodulated signal relations
4.2.3.1 100% square modulation
4.2.3.2 Partial sine amplitude modulation
4.3 Absorption lines shape
4.4 Position of absorption lines
4.4.1 Isotopic mixture cell – recordings of multiple lines
4.5 Intensities of absorption lines
4.5.1 Rotational temperature determination from relative absorption rates
4.5.2 Dynamics of helium molecule
4.5.2.1 Molecular and atomic density decay curves
4.5.2.2 Atomic and molecular coupled rate equations
4.6 Summary and conclusions
5 Investigations on Metastability Exchange Optical Pumping dynamics with blue laser 
5.1 Basics of MEOP
5.2 Achievements in MEOP in standard and non-standard conditions
5.3 MEOP angular momentum budget and laser induced relaxation
5.4 Description of MEOP experiment with blue light transmission measurement on molecular helium
5.4.1 Design of the MEOP experimental setup
5.4.1.1 General constraints
5.4.1.2 Nuclear polarization measurement method choice – pros and cons
5.4.1.3 Blue laser in MEOP setup
5.4.2 MEOP experimental setup – realization
5.4.3 Acquisition scheme and measurements protocols
5.4.3.1 Acquisition scheme and recorded signals
5.4.3.2 Measurements protocol
5.5 Experimental data reduction and processing
5.5.1 Polarization build-up and decay curve for Meq and Tdecay determination
5.5.2 Metastable atoms number density determination
5.6 Experimental results of MEOP with molecular density measurements
5.6.1 Discharge intensity
5.6.2 Results of MEOP – nuclear polarization values
5.6.3 Light induced relaxation and molecular absorption rates at Meq
5.6.4 Atomic and molecular metastable species density change with polarization
5.7 Absorption measurements in presence of OP pump beam at M = 0
5.8 Summary and the conclusions
6 Conclusion and outlook 
A Reference data on molecular helium a-e transition spectral lines
B Principle of laser absorption technique
C Sellmeier equation and dispersion coefficients for PP-KTP
D Constants
Bibliography