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The laser spectrum at t = 6 nsec. Axial cavity modes are visible in the laser spectrum. The arrow shows the spectrum of polariton condensation at the absorption line. Δω 12 /2π =-115 GHz.
Source publication
The generation of the ring mode-locked laser containing resonant absorption medium in the cavity was investigated. It is shown that near the strong resonant absorption lines a condensation of polaritons arises. Intensive radiation looks like as superradiance in a medium without population inversion. We studied theoretically the microscopic mechanis...
Context in source publication
Context 1
... pump laser frequency ω(t) ≈ ω 12 nonadiabatic quantum jumps occur, leading to the creation of superposition states in a resonant absorption medium and the generation short pulses of superradiance arises. Figure 2 has the spectrum of the laser after the build up of parametric resonance. The spectrum of the mode-locked laser becomes asymmetrical and expands to the direction of the resonant absorption. ...
Citations
... A particular sequence of pulses with phase modulation can enable this transition at a lower total energy. This feature can reduce the energy of the pump pulse by 6-8 orders of magnitude if we additionally utilize the excitation of the parametric collective resonances of an ensemble of atoms and the field in the cavity [9,10]. ...
Subject of study. The process of simultaneous emission of N coherent resonant pulses with different areas (-3π … 0 … 3π) from a short caustic (0.1 … 1 mm) of a focused resonant laser pump pulse in 87Rb vapor (resonant transition D2, wavelength 780.24 nm) has been experimentally studied for the first time. Aim of study. Development of laboratory prototypes of a new element base of resonant quantum microwave photonics for laser signal processing in the microwave region of the signal spectrum. Method. The effect of resonant self-diffraction of a short pulse is used as a method of pulse area shaping. In the caustic of the laser pump pulse E(t,x) = E(t)f(x), the spatial field profile has the form of a Gaussian function: f(x) = exp[- (x/s)2], s = 0.017 mm. The pump pulse must have a converging (for example, cylindrical) wavefront. The computer generated holograms (CGH) developed by us can be used to create an arbitrary f(x) profile. Main results. The process of simultaneous emission of N coherent resonant pulses with different areas (-3π … 0 … 3π) from a short caustic (0.1 … 1 mm) of a resonant pump laser pulse has been experimentally studied. With self-diffraction of the pump pulse, the number of emitted pulses with different areas reached N=16. The pulses were divided by the propagation angle in the interval [-5o...+4o]. The case of zero pulse area corresponded to the process of non-linear generation of a 0π-pulse with nonzero energy. It is noted that such a method of generating a 0π-pulse at a short propagation length has been proposed for the first time. Practical significance. The results obtained in the study of the process of self-diffraction of a resonant pulse with a spatial profile f(x) will serve as the basis for the development of prototypes of signal processing devices using low-power laser diodes.
