Photon effective mass

For small k//, the in-plane dispersion is parabolic (as depicted in the above equation) and therefore it can be described by a cavity photon effective mass M = iTi hnJcLc. This effective mass is very small, 10 me, and the dispersion can be measured directly in angle-resolved experiments allowed by the introduction of an in-plane component to the photon wave vector. Experiments involving off-normal incidence can also be modeled by including an appropriate in-plane wave vector for the field. 

The effects of the nonzero electric conductivity were further investigated by Roy et al. [20,50-52]. They have shown that the introduction of a nonzero conductivity yields a dispersion relation that results in phase and group velocities depending on a corresponding nonzero photon rest mass, due to a tired-light effect. 

Anisotropic effects of the recorded frequency of cosmic microwave background radiation have been proposed for photon rest mass determination [20]. 

Photon, see also Multiple photon entanglement effective mass, 22 energy-frequency relationship, 21 momentum, 22... 

It is helpful to compare the average carrier momentum with the photon momentum. A carrier with kinetic energy kT and effective mass m has the momentum... 

The proportionality constant Adirect is determined by the effective masses of the electron and hole and by the index of refraction of the semiconductor. Typically, the absorption depth /(Xdirect hv) of photons absorbed in a direct transition is 100-1000 nm. 

Hot carrier injection is favored in semiconductor electrodes which have a low effective mass for the minority carrier. This is because this low effective mass will produce more widely-spaced quantized levels in the depletion layer which then result in long intraband (now interlevel) thermalization times. Low minority carrier effective mass also means that the part of the photon energy which exceeds the band gap will preferentially go to the minority carrier this will produce hot carriers in the depletion region by virtue of absorption of photons with energy greater than the band gap. In this case, hot carrier injection is more favored in direct band gap semiconductors. 

With infrared-radiation pump lasers, where the frequency of the exciting photons approaches the energy of the direct band gap of several semi-conductos (e.g., InSb, PbTe), the effective mass m becomes very small and the light scattering cross section can approach one million times that of the free electron. The SFR cross section furthermore depends on the magnetic field strength. 

For 3.9 nm PbSe QDs, excitation with photons with four times Eg gave rise to quantum yields of 300% (3 excitons per absorbed photon). They attribute the high efficiency of multiple exciton generation as due to the small, similar magnitude of the electron and hole effective mass in the PbS(e) which reduced the Auger-like cooling ( phonon bottleneck ) which dominates in materials which have a much larger hole effective mass than electron effective mass such as CdSe and InP described above. 

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