Optical pumping of an optically thick atomic vapor typically requires a quenching buffer gas, such as N2, to prevent radiation trapping of unpolarized photons which would depolarize the atoms. We show that optical pumping of a trace contamination of Rb present in K metal results in a 4.5 times higher polarization of K than direct optical pumping of K in the absence of N2. Such spin-exchange pol...

We present a comprehensive examination of optical pumping of spins in individual GaAs quantum dots as we change the net charge from positive to neutral to negative with a charge-tunable heterostructure. Negative photoluminescence polarization memory is enhanced by optical pumping of ground state electron spins, which we prove with the first measurements of the Hanle effect on an individual quan...

2014 Optical pumping of ground state 3He has several peculiar features because nuclear polarization is first obtained in the metastable 2 3S state and then transferred to the ground state (indirect optical pumping); this introduces non-linearities in the equation of evolution of the populations. Here we present a numerical calculation of the kinetics of optical pumping in 3He, which allows a de...

The gapless energy spectrum of electrons and holes in single graphene layers (SGLs), graphene bilayers (GBLs), and non-Bernal stacked multiple graphene layers (MGLs) opens up prospects of creating graphene-based terahertz (THz) and infrared (IR) lasers. The interband population inversion in such lasers can be achieved, for instance, by optical pumping [1]. However, the excess energy received by...

We demonstrate that optical pumping plays a significant role in determining the noise in certain types of laserpumped vapor-cell microwave frequency standards by changing the way in which the laser’s FM noise is converted to AM noise by the optical-absorption profile. When this FM–AM conversion is the dominant noise source, the noise spectrum of the transmitted intensity can be dramatically alt...

In the present paper, the problem of multi-pumping all Raman amplifier has been investigated to obtain a maximum flatness gain and increases the bandwidth of the cascaded Raman amplifiers over a wide range of optical signal wavelengths for long-haul ultra-wide wavelength division multiplexing (UW-WDM) transmission systems due to multi-pumping wavelengths and pumping power . Three cases are anal...

Fibre Raman amplifiers are being deployed in many new long-haul and ultra long-haul fibre-optic transmission systems, making them the first and most widely commercialized nonlinear optical devices in telecommunications. One of the main reasons for this is their improved noise figure and reduced nonlinear penalty of fibre systems hence allowing for longer amplifier spans. In this paper, we have ...

In this seminar we present the structure, operating regime and use of solid state laser with passive Qswitch. We give a description and comparison of two basic concepts of optical pumping, the lamp pumping and the diode pumping. Finally we present the Q-switch theory and more precisely passive Q-switch theory.