Stability theory of class-C (far-infrared) lasers with an injected signal

Abstract

The behavior of a single-mode class-C laser in the presence of an injected signal is investigated theoretically in detail. We have determined the ranges of input signal strength and the frequency detuning for which the oscillations of the cavity electric field and the atomic induced dipole moment are simultaneously stable and have only one oscillation component with the frequency equal to that of the input signal (injection-locked state). One can reproduce all the previous results corresponding to class-A and class-B lasers from our results by using their relevant conditions. Finally, the energy conservation law is demonstrated for both the below-threshold and the injection-locked states of class-C laser amplifiers.

Detuning Effect Between the Cavity Resonance and Atomic Transition Frequencies on Noise Flux Profiles of Class-C Lasers

“…which is four times larger than the below-threshold gain to noise ratio (21). The conditions of larger gain G H (ω) > N L N (ω) is here satisfied by the wider damping ratio of cavity mirrors Fig.…”

“…In contrast, the above-threshold state is distinguished by the following trial solutions (7) in order that by substituting them into equations (1)-(3), we derive the below solutions for the statics population inversion D 0 , and for the mean number of coherent photons |α L | 2 that are oscillating at the laser frequency ω L in the forms [14], [18], [21] …”

“…The normalized pumping rate C = γ || D P /γ || D 0 has a value less than one in the below-threshold state (C < 1), and a value larger than one in the above-threshold state (C > 1) [21]- [24]. The stability theory urges an upper limit for the normalized pumping rate C in the above-threshold state for the case…”

The forming mechanism of spontaneous emission noise flux radiated from hydrogen-like atoms by means of vibrational Hamiltonian

“… were determined by inspiring from the stability theory of lasers [8]. The vibrational motion equations of diatomic molecules have then been derived by applying ) 3 ( Ĥ into the Heisenberg equation.…”

Four-wave mixing and generation of short pulses in multimode class B laser amplifiers

“…This is one of the mode-locking techniques in which the temporal specifications of pulses are directly determined by choosing the phase, frequency and strength of the injected signal [2][3][4]. It is also used to reduce the frequency bandwidth [5,6], the noise [7,8] and the instability [9][10][11][12][13][14] of lasers.…”