The transient behavior of a laser is discussed using the quantum theory as did Scully and Lamb. The formal solution of the density-matrix equation is expressed in terms of exponentially decaying eigenmodes. Some of the lower decay constants are obtained numerically. The equations for the moments of the density matrix are then derived and solved by a truncation method. The equations of motion are integrated numerically for the case where the average number of photons in a laser cavity has the realistically large value 1.3 \ifmmode\times\else\texttimes\fi{} ${10}^{5}$ . An alternative Fokker-Planck-equation approach is discussed.The transient behavior of a laser is discussed using the quantum theory as did Scully and Lamb. The formal solution of the density-matrix equation is expressed in terms of exponentially decaying eigenmodes. Some of the lower decay constants are obtained numerically. The equations for the moments of the density matrix are then derived and solved by a truncation method. The equations of motion are integrated numerically for the case where the average number of photons in a laser cavity has the realistically large value 1.3 \ifmmode\times\else\texttimes\fi{} ${10}^{5}$. An alternative Fokker-Planck-equation approach is discussed.

Physical Review AAug 1, 197321 citations

Quantum Theory of Laser

Masahiko HIROOKA, Sigenobu Sunakawa

The Review of Laser EngineeringJan 1, 19860 citations

The theoretical study of terahertz-streaking photoionization for ultrafast imaging of density matrix in rubidium atom

Zhong-Huo Ling, Shuai Wang, Jincang Zhang +3 more

Terahertz-streaking photoionization can be exploited to resolve ultrafast quantum beating and reconstruct the ultrafast evolution of density matrix. Here, we propose an experimental strategy to implement the method merely with the tabletop femtosecond system and magneto-optical trap reaction microscopy. The probe pulse consists of an ultraviolet pulse with pulse duration of about 30 fs and a strong terahertz pulse with strength of about 2.6 fs in rubidium-atom superposition. The population and coherence terms of the density matrix can be projected into different positions of the photoelectron momentum distribution. The reconstruction algorithm was designed to acquire the ultrafast evolution of density matrix from the time-dependent photoelectron spectrum. The experimental conception can demonstrate the newly proposed transient spectral method only with the commercial femtosecond laser system and magneto-optical trap reaction microscopy, thus preventing the complex laser system, such as extreme ultraviolet free electron lasers and attosecond higher harmonics, allowing a new metrology to explore the coherence dynamics of quantum systems.Terahertz-streaking photoionization can be exploited to resolve ultrafast quantum beating and reconstruct the ultrafast evolution of density matrix. Here, we propose an experimental strategy to implement the method merely with the tabletop femtosecond system and magneto-optical trap reaction microscopy. The probe pulse consists of an ultraviolet pulse with pulse duration of about 30 fs and a strong terahertz pulse with strength of about 2.6 fs in rubidium-atom superposition. The population and coherence terms of the density matrix can be projected into different positions of the photoelectron momentum distribution. The reconstruction algorithm was designed to acquire the ultrafast evolution of density matrix from the time-dependent photoelectron spectrum. The experimental conception can demonstrate the newly proposed transient spectral method only with the commercial femtosecond laser system and magneto-optical trap reaction microscopy, thus preventing the complex laser system, such as extreme ultraviolet free electron lasers and attosecond higher harmonics, allowing a new metrology to explore the coherence dynamics of quantum systems.

Acta Physica SinicaJan 1, 20200 citations

Intersubband laser coupled three-level asymmetric quantum wells: new dynamics of quantum interference

Danhong Huang, David A. Cardimona

The improved density-functional theory is employed to obtain the eigenstates of electrons in an asymmetric quantum well. On the basis of calculated eigenstates, the semiconductor Bloch equations are used to calculate the transient density matrix when a pulsed intersubband laser coupling is applied to the system. The new dynamics of the individual absorption peaks is analyzed for the first time by use of a self-consistent-field theory. Based on this, the time-averaged optical spectrum is calculated to show the coherent-transition-induced quantum interference in the system. The new phenomena of probe-field amplification is observed, and the threshold laser intensity for observing it is given.The improved density-functional theory is employed to obtain the eigenstates of electrons in an asymmetric quantum well. On the basis of calculated eigenstates, the semiconductor Bloch equations are used to calculate the transient density matrix when a pulsed intersubband laser coupling is applied to the system. The new dynamics of the individual absorption peaks is analyzed for the first time by use of a self-consistent-field theory. Based on this, the time-averaged optical spectrum is calculated to show the coherent-transition-induced quantum interference in the system. The new phenomena of probe-field amplification is observed, and the threshold laser intensity for observing it is given.

Journal of the Optical Society of America BMay 1, 199811 citations

{10}^{5}

. An alternative Fokker-Planck-equation approach is discussed.